TSP #100 - Tektronix RSA607A Real-Time Spectrum Analyzer Review, Teardown & Experiments

hi welcome to single pad in this episode I have another product review for you guys we'll be taking a look at this Tektronix RSA 607 a which is a 9 kilohertz to seven-and-a-half gigahertz real-time spectrum analyzer with a 40 mega analysis window it also has a built-in tracking generator that's capable of measuring return loss directly on the instrument which is fantastic and it works with this signal view software platform which we came free a couple of years ago now since I did my first USB spectrum analyzer the review for take a couple of years ago they've been hard at work and they've made quite a few new instruments based on the same platform they even now have a network analyzer on the same form factor as this one I'm hoping to get my hand on that and do a review on that one as well now there's a lot that I want to show you about this we're going to take it apart ago and take a closer look exactly what's going on inside and a whole bunch of different instruments to take a look at its capabilities some of these weaknesses and see if it fits your application so let's get started so we can look at the line of USB based instruments that techtronic has to offer and if you look here's a couple of them listed here now when I preview the rsa306 a if when it first came out I was really impressed with the fact that they made this signal view software completely free and it's still free of course it has 17 different measurements that are included in it by default and some of the other advanced measurements like demodulation and as well as compliance and so on obviously going to have to pay for but I've reduced the prices of those significantly as well and all of these instruments work with signal view and this software runs across all of those spectrum analyzers making a cohesive unified platform that you can simply jump between very quickly I had no idea that they were going to go ahead and develop so many USB based instruments now they even have a network analyzer which is a in the same form factor so it's really good to see that so we're looking at the RSA 600 here and if you look at that and the RSA 500 and 600 essentially the same thing except one is battery-powered and now in this particular unit you can go all the way up to seven and a half kilo stone from nine kilohertz and we have a 40 megahertz capture and analysis family now the price is between six thousand to ten thousand and it's a great price it is extremely competitive even to companies like Vigo if you look at the rival spectrum analyzer the TG DDS a85 70 G which is has essentially the same spec seven and a half gigahertz a good maximum frequency but he has no real-time capability and it doesn't have a signal blue software that couples do it and it's the same price so they're really going after the market and I don't think there's anything like this on the market right now with these capabilities at this price price point given that you can always expand its capabilities through signal view with additional compliance and demodulation capabilities and so on so it's really impressive and if the great sign for the industry and for everybody who's buying these things because it just means they're going to get cheaper is going to get more capable and tech is serious about these units and they want to basically capture this market and end up doing a great job with it so another we have an idea of kind of what's going on and what the offering is now we can go ahead and actually take a look now first of all I want to take it upon I want to show you what's inside of it how it's built what does it look like how does it compare to the battery-powered version of the same instrument and then we're going to do all of our experiments with it so I'm really excited to get started so let's take a look at the front of this unit here we have obviously the USB 3.0 connector with a screw in terminal it comes with a special cable that ties into this and it protects it from getting yanked out or bent or broken this is particularly useful for the version of this unit that is battery-powered for outdoor use and this would be pretty handy as you're moving around you want to make sure it doesn't get pulled out or damaged so we also have the power LED and activity LED and turn on for GPS of course we have the RF add for the tracking generator as well as the reflected wave going back in and this is means that you can do your return loss measurement without the use of an external directional coupler which is a huge advantage so I will talk about I will do measurement on this there is the reference input for 10 megahertz triggering so we can trigger on a particular digital activity through a signal view software of course and the RF n which can take 40 volts as well as 33 DBM so 3 DBM more than typically you will see on a spectrum analyzer which is pretty handy especially when you're outside and trying to connect to some unknown signal so nice pretty straightforward now you may ask why is this in the front it would be for the benchtop into the instrument like this I would prefer to have this in the back of course there's no reason for it to come out for an outdoor unit battery power that can understand but once I take it apart and take a look inside as well as looking at the architecture will become clear why they had to put it in the front of the unit and also because the battery powered version has to have it in the front so yeah it looks good let's take a look at the back of the unit and at the back of unit pretty straightforward we have the AC line going in we have the fan of course and we have the 28 Volt noise source control for the output of the back now I could not find a way to activate this 28 volt source through the signal vu software it's probably a feature that hasn't been implemented yet or if it is somewhere in Sigma group it is really buried into all the settings because I could not find it now this would be obviously used for measuring noise with an external noise source and I would love to do that and I wanted to show it on camera but I couldn't find a way to access that so it's probably not implemented yet but it's good to note it is there meaning that eventually this instrument will be easily retrofitted to be able to do noise figure measurements all right let's take a look inside this unit I've already taking the top off and take a look how nice and clean the design of this year that actually is is also really module and that module design makes sense to me because as I showed earlier there's a version of this instrument that has a battery powered basically and it had the same RF specification as this one so it would make sense to use the same RF thick and the same digital deck and share it between those two designs to reduce the cost of development and at least this is what I think is going on over here and as you can see they pushed out the design of the power supply then the fan the AC line coming in in the 28 volt for the noise source completely outside of this because it's not shared with the other instrument and the design is really simple the power management of this board has requires only three wires and perfect for battery-powered application now in this power supplies which is from XP power it says output one is at 12 volts now there's three wires here so I suspect there is an output to perhaps five watts parameter but surprise that is not listed here either way the simplicity of this is really in line with having a battery-powered instrument this line over here is nothing twenty-eight volt control to turn on and after 28 Volt noise source and there's the DC DC converter on this board over here because this guy doesn't generate two of 24 volts obviously you're going to have to step that up and interesting also to see that the fan control directly comes from this board and they just for simplicity they have basically put that design onto this board as well again I think this is unique only to this instrument not to the power at the battery powered version of this AC line is all good everything is tied down very nicely on this board as well mechanically it's nice and solid there's nothing unusual going on over here just a couple of connectors over here that are not used I wonder if they're I use this looks like a more other power connector perhaps for the battery pack for battery balancing maybe I'm not sure but there's a bunch of stuff that's not used which may be indicated that this is the same design using two places there's also some connectors over here which we'll take a look at for programming and configuration perhaps there's a button over here interestingly and I will take a look at that as well but other than that really pretty straightforward and now there's one other thing I wanted to mention here is that you could potentially if you only wanted to figure out a way to retrofit this with the battery yourself and obviously the warranty and stuff would be out the door but there's nothing stopping you from trying to do that given how simple the design of this particular power system is from this point of view now there's a lot of empty spaces in here you may ask for why all the empty space but because they want to make likely they want to make the length of this device to be compatible with benchtop instruments and this stacks quite nicely on top of that they killed Keithley source meters and other multimeters and so on so I think this is for consistently with those and otherwise it's quite nice and no complaints there but we got to go a step deeper and here's where all the magic happens I've taken the board out and it's just so nice always such a pleasure looking at well design and mechanically engineered instruments there so obviously this is all enclosed for various reasons as well as isolation protection heat sinking as a lot of reasons why they do this so let's go ahead and take the top off and let's see what's on the board then and also the bottom and so we can take a look there's it there is a sticker here for warranty so I'm going to take that off I think it's well worth taking a look to see what's inside this so here the top and bottom blades of the RF and digital deck and look how beautiful they are obviously you've seen these before in many of the tears and that I've done in the past you can see conductive sections that touch onto the PCB and create a nice shield there each individual segment is typically for a separate function so that they don't interfere with each other various filters and synthesizers and so on would be in different sections as well as the digital blocks several pedestals you can see in a couple of locations on top of them there's thermal putty those touch some of the higher power components there so that they can take the heat out of the unit so that the idea the unit doesn't obviously burn up and the a improves the age of the components a couple of places over here you can see we have absorbers on some of the critical places for example at the input RF section we have absorbers and some of the synthesizer sections in the corner we have absorbers to make sure that first of all we don't build a resonant cavity inside this as well as we don't get multiple reflections building up you get a standing wave inside a cavity to which you don't want of course and yes it other than that looks pretty nice and straightforward very clean so let's go and take a look at the board itself and here is the RF board and and the digital board as well and it looks so beautiful so let's take a look at some of the components I'm not going to go into too much detail there because I've talked a lot about these these different components but it's still interesting to kind of see the signal flow here and see what happens to their various components here's our tracking generator output here's our RF input so naturally we have an AC coupling which is the very first thing this port sees as well as a whole bunch of switches that switch to different bands we've seen these third stage switches and attenuators being used in the front end first to switch attenuation as well as to switch to different bands and these bands and separate the frequency into multiple sections processed by different mixers and different filters and this is critical to get good a harmonic rejection and harmonic behavior from the whole instrument so here you can see for example one path here and one path here on this path we see a whole bunch of microwave filters again we have some Chronicle filters some LC stop filters over there going into a mini circuits double balanced mixer there and you have the three components here these are hybrid microwaves and filters and exactly don't know what the part numbers are because I don't want to take these covers off that it would be hard to put these back but these are typically hybrid modules you can buy them and they come in and separate and solder will reflow package there and inside the package there's a cage as well as you could even use other fancy materials some of them can use ceramics for very high quality filters if you need to this could be soft filters or who knows what they are but either way it is clear that they are filtering the signal in multiple stages that there's another double balanced mixer here here here's yet again another mixer there here's another soft filter you can see there's a couple of these also on this board now this board has tons of tons of synthesizer art I mean their synthesizers here there are here there's a whole bunch on the other side and there's a whole another synthesizer sorry there's another step attenuator here it's obviously step at Unity controls the power coming out of the track in January there's a multi-port switch RF switch here getting signal from a couple of different places before sending it out likely because they're different synthesizers covering the full band so this is how they probably select that whole bunch of microstrip help in filters here again you can see switches that select between which filter has been used separating the band that is being processed by various different kinds of filters so really quite beautiful on this side now if I flip it to the other side you will see a whole bunch of other components again on this side we see a few other interesting things now this is the GPS antenna so therefore clearly this is our GPS module a whole bunch of DC DC convertors sections over here a Spartan six FPGA at this I see here is directly connected to the USB 3 it's a little hard to see the partner of that suspect that it has to do with the USB 3 management device there and this is one of the ones that's heatsink so there's a lot of data going through this I see because this is constantly working when it's running as I'm some a few more filters I don't want over there here's the vcxo of high quality VCO there's a linear devices synthesizer yet again and I synthesizes there there's just so many synthesizers all around here is the our ADC this is a 12 bit up to 105 mega sample per second I believe a DC I think it's from linear technologies as well if I remember correctly yep I think it is so it is the 12 is a to D converter which again makes sense and you can see the AF path coming in different locations and then going into the ADC very classic architecture obviously Devils in the details but you can clearly see what they're doing another interesting thing I came across here is that this section over here this I see over here is the linear devices sorry linear technology battery management IC and charging ICS so I was definitely right about the fact that this connector is for the battery and it's interesting that this part is conformably coated and the other side as well but not everything else suspect this probably has to do with the fact that this is dealing with a battery and they want to make sure that it is perfectly covered and protected and they don't obviously don't want to put conformal coating all of your RF sections it will be quite quite bad for it but depending on the dielectric properties of the conformal coating but I suspect it's never optimized really for RF performance so you don't definitely don't want to do that but this section dealing with the battery being critically sensitive to moisture and actually being dangerous in case that something goes to the battery perhaps this is the reason why it's conformal according this fuse in there as well another mixture over there and I was saying that the medicine decides over here is just full of different sections it's really beautiful very nice design again to be expected they have really perfected the design of this now if you look very carefully you can see the footprint strategy makes sense as well so there's a line over here everything on this side is RF energy on this side has a digital part in it so you process the RF here you generate your synthesizer here you do that conversion you do filtering everything over here and then ends up at this side of the if' going into the ADC going into the FPGA so this section is all digital battery management action GPS receiver USB communication Spartan FPGA if' processing and digitization very separate from the whole section that does the main RF down conversion all that makes sense is that this is obviously you want to do then it sounds really simple when you look at it from what this point of view but imagine you have all these components you need to lay this board out there's a lot of trade-offs you need to make to make sure these things actually line up and how you strategize to make sure the signal flow actually flows in this direction look up this is exactly the flow of the signal coming in and going out so there's a lot of thought that's going into this really beautiful component placement quality is tons and tons of components from basically the best vendors in the industry for ASIC for these components and they've used them all so yeah no complaints really about this or not you have to look at this performance but I would say from the experience they have gathered making other USP a spectrum analyzer to this point this is going to perform quite nicely so I'm eager to put it back together get on a bench and do some experiments with it so there was one other little thing I forgot to mention while I had it open these coaxial connectors are actually spread throughout the entire board allowing them the technician or the whoever's testing the board to be able to monitor various signals across the entire RF deck and here on the outside there are two of them and in between there is a coplanar waveguide and it looks like that they're using these to characterize the board perhaps afterwards to make sure to see what the losses over there you can see how their solder mask is taken away from the canary waveguide section there to improve its RF performance so there's a little tiny test structure on this board allowing them to characterize it it kind of looks cool now let's see if we can use this instrument to reverse engineer an RF transmitter that we don't know much about this particular module here is from a drone remote control now this is a very simple one doesn't really have much stuff on it but you can see the two actuators used to control the drones location as well as some of the view screen for feedbacks and buttons and so on plus really not much going on here this is a fairly simple one doesn't have that many channels but we don't know anything about it I don't know where the carrier frequency is I don't know what modulation for my reducers or highlighting cause the data when it's transmitting it I want to see if I can use this instrument to figure all this out now let's take a closer look at this year so on the other side we will have a couple of components so we have this hitachi component here which just controls the LCD screen nothing that interesting there and there is a component whose numbers have been rubbed off and that most likely is a microcontroller handling the switches and reading data from the potentiometers and little actuators and then digitizing them and sending them to the RF transmitter module and they have gone through the trouble and actually spray-painting the back of the RF module which I feel cars are necessary I mean first of all paint comes off and really do you really need to do this on something so inexpensive but anyway so let's go ahead see if we can figure out how exactly it works in the place where there used to be an antenna I have solder on SMA cables so we can connect the SMA cable directly to the input of the spectrum analyzer and we don't have to do measurements over the air which would be quite unreliable and difficult to do not just because of multipath and attenuation and so on but because this may be operating here is M bands there's a whole bunch of traffic here in the lab from routers and a ZigBee switches and all a whole bunch of other things and we will interfere with us so let's go ahead and turn it on so I'm going to connect it directly to my Keithley 22 ATS power supply this is a really nice power supply of using it a lot lately - very fast reading it at six and a half digit monitoring there so I've already set it to six volts 2.1 amp let's go ahead and turn it on and let's go down here and see what it looks like there it is you can see that it's powered on and at the beginning a lot of these drawn remote controllers need you to actuate the up and down a couple of times before it comes online so we're going to go down up and down and now it's green and used to actually have a buzzer here that I'll remove because it's ridiculously loud so now you can see on channel one it's connected to the up and down position of this particular control there you can see goes from zero to 100% and if I push it left and right you can see the channel will change and now a different channel will show me numbers so you can see the different channels that are active to use channel three up and down and then there's channel four left and right so and there's a whole bunch of buttons for calibrating the locations your the zero default location so it's obviously sending some data out now let's go connected to the spectrum analyzer and see if we can figure out exactly how it works which would be pretty interesting all right here is our setup very straightforward the antenna directly connected to the input of the spectrum analyzer nothing fancy going on now we can go ahead turn it on and let's go to the PC and see what we can find out all right so let's go and try and find our signal now the easiest way to find it is obviously to look at the entire span of the spectrum analyzer so let's go ahead and click that and now we're going from nine to door so seven and a half years and we should be able to occasionally catch all these signals and there is a good we just caught one over there and if you wait long enough you will see another one there's some more here and you can see that there's a whole bunch of activity here that are happening around this is M bandit 2.4 giggles now you're not going to catch every every time there is activity because it's sweeping very slowly and you're going to miss a lot of these tones that are coming at you is a full one actually cut cop the entire package so you see that whole power and sometimes you will see some terms appearing out here which are the harmonics of the main zone coming out that's not a very good chance that you shouldn't really put that tones outside the frequency you're supposed to be operating there but anyway this is a pretty inexpensive component so now that we know that signal is present around this table there's the hammer I was talking about so now that we know that these signals are here we should be able to zoom into there and and take a closer look so let's go to the 2.4 gigahertz band there and we're going to change your span through 40 mega so there yes we can see a whole bunch of activity and now we can go ahead and create another trace let's say trace number 2 and in this trace we're going to do a max hold I'm going to show that trace and you're going to see a whole bunch of activity being recorded eventually you see we have a lot of the signal there's a couple of things to note here even though there are distinct tones that appear there's a whole bunch of other power in the look at this big big amount of power coming out some of this is because it's just a bad transmitter some of it could be pilot stones and preamble tones and other things coming at you also notice that it goes beyond the 40 mega analysis going goes up goes the other 2.4 to bigger set so I can shift the frequency higher so we can see more tones so instead of 2.4 let's say we can go to 2.45 another 50 makers up and you can see some more activity again so 40 mega is definitely not enough to see all the frequency content this transmitter is putting out at once you can see individual tones but not all of it now would be great if this had instead of a 40 megahertz bandwidth let's say 110 Mageau standard but the challenge with that is that on a USB instrument like this one if you were to increase that span from 40 to 110 aside from all the hardware difficulties from the RF portion itself you're going to have to send a lot more data to the PC so maybe next generations of these instruments from there is USBC and thunderbolt and so on they would be able to have higher analysis panel but 40 mega s is plenty and there's a lot you can do with just for omega as you will see so now you can see that some of these tones the power is quite a bit large as larger than the 0 DBM here so let's go and change our reference level and from 0 DBM to like 5 6 dB so now we want to saturate the input so there you go looks good so this is a nice place for us to start so let's go ahead and add a GPX window now here it's going to be the real-time VPX analysis now we're going to be able to see much better what's going on my computer is actually quite slow here so here we go and there it is and check it out I mean it's just a jungle out there it's jumping all over the place there's a lot of other tones that come and go even though it looks like that these stones are on at the same time but that's just a residue from the DP axis a window that I can change the time constant of these display waveforms there it's about ten to ten to a hundred thousand spectrums per second but there's only one on at a time and by looking at this you would be merely recognize that this is a spread spectrum communication systems that frequency hopping and the way this frequency hopping spread spectrum systems work I've talked about this before sometimes they fall at predetermined a sequence of channels sometimes it's random sometimes it is encrypted advertised and sometimes they send a preamble so that the receiver can lock the channel so they kind of prep the receiver say I'm going to be transmitted at this frequency the receiver catches that locks on to it and then that packet of data actually comes following it so we can find out exactly what it's doing by taking a closer look at these pulses and they come out let me go ahead and turn this trace off so right now the way it is is really difficult to use because we have no trigger reference so we can go ahead and define it figure reference so we can make and measure with respect to a repeated event so that's pretty easy to do let's go and add a couple of other windows let's add a time overview window and in spectrogram window and now we don't going to get a bunch more that's going to take a bit of time again my computer is not very fast yet there is so you can see that occasionally on this time overview you can see these pulses come and go but you're looking at only a 7.4 micro second duration so obviously we're not going to capture everything but as you can see is when it's sending data that I'm interested in it exceeds about minus 3 DBM of power it because even above 0 DBM but minus 3 DBM seems to be a good reference point for us to use for triggering and this instrument obviously supports triggering so let's go ahead and define our trigger so we can do it either on the falling edge on the rising edge of the signal now generally when packets are sent it may be that they have a small they had a slow start and they may have a preamble or a pilot at the beginning so it might be difficult to trigger on that but once the target is done they collapse the alpha power so we can use a falling edge in this case and let's set the level to let's say minus 3 DBM and we can go ahead and enable the triggering from free-run and there it is look at that we're catching the falling edge of an individual packet now we're looking at again at a very small window we can change that let's go ahead and look at 500 micro seconds like that and yuria we can see we are triggering right over here and we are catching one of these packets but it doesn't seem like we're looking at a long enough duration I want to see more than one packet so I can get some information from that let's look at one millisecond so here's one millisecond and there it is look you're actually able to catch two packets now this is trigger point is on the falling edge so let's move the trigger point to the left let's go all the way to let's see not the fastest computer in the world where can I go let's setting probably about maybe 200 and 250 microseconds would probably put spot there you go you can see it's moving into the center I'm recording the screen here as well as a bunch of other things so it's not nicest PC at the moment there we go maybe 250 would probably be a good place to stop and do this and we go take it out that we can see exactly the activity that we're interested in following now there's a lot we can look at this let's pause it for a second so and take a look so we have four windows here one is our spectrum and this orange line is the instance of the spectrum versus time that we're looking at a particular time I'll share with that meet in a second here's a VP x2 the bunch of activity going on here's the overview of versus time and here's our spectrogram so let's put a marker on this now all of these markers on all of these screens as well as the claws are time-correlated this is why it's so useful to have a software coupled with this instrument as I've said before if you're going to make a USB based instrument or any instrument if your software isn't great then you can have the best hardware in the world and you wouldn't matter so here this time correlated measurement is extremely helpful so you can see on the spectrogram some activity shows up hot means power is coming here and this activity here you can see that that pulse right there if I follow that go to the next one that's this pulse over here and then the other part is outside of the screen so when I'm here I can clearly see that there's two pulses in a row and they're quite a bit different from each other even though they look very similar and the difference is that the duration of this first Hall is quite different than the other one so this is a much shorter pulse than that so what could that possibly mean well it could be that the transmitter first of all sends a small amount of power here this could be for alignment of frequency detection from the receiver I'm not quite sure white students in Navy doesn't seem to be high enough to do that but anyway sending this CW tone at the beginning and then it ramps up the power and then it keeps the power steady this is doing something new in this portion and then drops the power wait for some time and does it exactly the same thing again but this time longer now it could be that during this packet of data it's sending its ID so that the receiver knows that the tracker is talking to it and not some other receiver sitting on the same channel so back for example is one possibility and then it sends a longer packet so that perhaps the receivers say okay now this packet is mine the one that the one that actually that considered this to be aimed at that particular receiver so we are interested in looking at both of these but it's likely that the longer packet is the one that contains the data related to this states of the actuators and bottoms of the transmitter itself so it will be better to look at this one we can look at both of them but it will be better to look at this one I figured out what's going on now given that the amplitude is so constant it is possible that this is for example a an SSK system the frequency shift keying system so we should be able to look at frequency versus time during these packets in order to make sure that this is indeed sending data here in that time now as I was also mentioning if I go over here during this packet I can actually clearly see the spectrum and I can see how the spectrum evolves between the packet there is nothing and I go back up I get my spectrum back and the next packet and so on so it's very clear what is happening in these spectrums by having these windows at the same time so let's go ahead and run it again and you can see that sometimes the distance between these pulses changes it's actually a little bit misleading the reason this happen is difficult on the falling on the falling trigger point you could it sometimes it triggers on the longer packet than the shorter packet you can see so it that's why it shifts around this is it a common problem now normally you would want a more advanced trigger menu but this doesn't give you dwell time for example doesn't tell you hold off doesn't give you any of those abilities that at least that I could find and the biggest limitations of this is the fact that the trigger band is not changeable so this I'm not sure how difficult it is to do this in soft grip and if they can be implemented later but it doesn't matter what bandwidth you're looking at it will always trigger at 40 makers but if I want to keep this spectrum steady it means that I am only interested working at let's say one channel only so I can Center the screen so I can say go to the center frequency you have two point four six five let's say he goes and in the center that's one of the channels you can see it sometimes shows up here so what if I want to only trigger if the signal is on this channel and I could do that potentially by reducing the span just around this tone so that it doesn't see the tone that for example shows up here but unfortunately it will still trigger even if I'm not looking at it outside of this window so if this is something that limits you and makes it a little bit difficult to look at this data especially for a frequency hopping system like this one you can of course pause that stop it and then replay they're the ones that you want to look at but then doing your live measurement make ups more difficult so let's go ahead and try and see if we can look at it so you're going to have to add another for this so we're going to go ahead and add a frequency versus time window because we think that this is an SSK system so let's go ahead and add that and there is the window so now we have all of our information that we would need to decode this instrument this is a mysterious transmitter here so this packet packet here is obviously correlated to this portion and this packet over here is correlated this portion you can see how it's jumping around and you can see how the standard frequency of the packet changes let's forget these jumping channels so it can see there's one channel or sometimes it catches this channel sometimes it catches the other channel and this is where the trigger would be so useful I could tell it only trigger when you're on this channel but unfortunately I can't do that so it's going to be a little bit difficult so now I want to zoom into here and figure it out a little more so let's let's pause this for a second so I can zoom in and the zoom again this is not the friendliest thing so you can zoom you can't just drive draw a rectangle and zoom which is the one that most people are used to you have to zoom in horizontally like this and then vertically like this which is a little bit a little bit tricky but there we go and then you can just pan it there are our bits look at it it's like a it's like a magic thing you can clearly see the bits here so I can move my marker over here there now you can see my marker individual bits as a function of time showing the frequency deviation looking at the spectrogram and looking at this fraction at the same time it's wonderful I mean this is what you want from an instrument really giving you every piece of information at once there it is and then we can see a nice fairly noisy let me run it so you can see that it sometimes goes away outside of the screen and that's because it's not always catching the same window but anyway there's nothing I can do about that unfold at least I couldn't figure out a way to to get this to stay steady here let me try a different a slightly different frequency to point four five six gears let me see what happens if I put it there you can see now is caching caching the other Channel first huh yeah it's not that's not exactly what I want but it's close enough for our purposes so there is our hope to 0.465 gigahertz so there's a center frequency it's going to show up there Delta so this is the one we want so let me pause it and I can go ahead under view and I can go under replay toolbar and it has everything that he has saved I can go ahead and replace I can go back and there it is so we have now one packet now take a look at this as I said it's noisy because we're looking at a very large bandwidth but I can change that so I can go over here and I can go under its settings and I can say do not link the analysis to the span look at the smaller window look at it 10 makers window for example so now if I run it again next time I catch it a sequence it's going to be a presenter of course it's going to be much cleaner if I can catch four letters let's see where did it go I lost it did I lose it all right I found a somewhat acceptable solution and what I did is that I changed my standard frequency to two point three eight five gigahertz and our analysis is now done around that Center frequency now it happens that only one channel from our spread-spectrum transmitter falls within that bandwidth as a result of that the trigger can only happen on that one channel because the other ones which are simply outside of the measurement bandwidth we won't be able to see the other channels anymore but this should be good enough because these are all the same the area that comes out of the channel is just jumping around there's one way to work around it but unfortunately now you're going to be missing there any other spectrum outside so if there's an issue with them you won't be able to detect it in this condition but good enough for our purposes we still have the issue that the trigger sometimes triggers on the long post as opposed to a short pulse and that's why it's jumping around still and that needs a dwell time or a hold off time in the trigger menu to resolve that and I really hope that these two changes would be implemented because there would be an enormous advantage to be able to have these because as you can see the limitations of not having these two trigger functionalities make the measurement quite a bit more difficult now let's look at this now obviously we can see the bits but it's not very clear and that's because we're looking at a 40 megahertz bandwidth to do this measurement and that's not really a good idea because these are much smaller channels no reason to try and do FSK computation on an entire 40 mega s channels it's going to eat into your dynamic range and they follow up this and we can actually change that setting so it says link to span I can remove the measurement bandwidth so that it doesn't it's not linked to the span I can remove that and I can change that let's say I'm going to take only a 5 megahertz bandwidth but as soon as I do that I'm going to lose my measurement because by default this 5 megahertz analysis is done at the extent of frequency of 2.38 5 Biggers but that's not what our channel is our channel is all the way out here so we're going to be missing the data completely because we're looking at this area well they thought about that as well and we can make that change too so here there is another button that locks the center frequency to the measurement frequency then we don't want that and removed head and we're going to stable our measurement frequencies around over here so I can actually move the manually myself and put it right where I want it to be which is somewhere around here that should get there you go so now we have our measurement around that frequency now we don't see anything again unfortunately I'm gonna have to also scale this and there it is now we see it again and I have to zoom into this again let me join and come back I'm sure you don't enjoy me zooming through this meter and here we are check it out the bits are very nice and clean and clearly see individual bits and transitions between them and so now let's take a look and see if there is any correlation between these bits and the settings on the controller itself so I can go ahead and change one of the actuators that example push the forward and backward and movement and see if any of these bits change so have your eye on it and forward and check it out right in the middle and backwards you can clearly see how it's counting so it's converting that voltage to digital the potentiometer and then sending that through this particular set of bits to do this packet of data so this packet of data is partially you can see this section of it is responsible for that potentiometer what about another one let's go to the other side of the controller I'm going to push it forward and check it out right over here these bits I can go the other way these bits are responsible for the other side the other actuator and if I go left and right here's left take a look over here in the center to the right there it is so each section of these bit sequence is dedicated for the setting and the status of one of these individual outputting shamanism if I push a button let's say when repeatedly push this button check it out right here this bit every time that that is there means the button was pressed see that you know this yeah it's it basically this is what you need to do to reverse engineer it and you can now correlate each of the bit sequences to a particular component on this board and then you can find out what message is being sent what the sequence is how the bits are converted to digital and it's all in there if I go over here and look at this sequence here I will be able to see the channel ID that's being sent which has nothing to do with the settings of the controller so all of this is possible because of doing this real-time measurement and being able to do frequency versus time Africa versus time if this was a ASX system for example and showing all at once and having clear indication of exactly what's going on in the transmitter just think about where we started from we started from some random spikes on a spectrum analyzer that would occasionally catch every once in a while to be able to completely decode the message that's being sent by the transit all in one without in one software or in one instrument without having to do anything else so I'm really happy with the performance of this and it continues to grow and continues to get better of course but is triggered limitation and makes it a little bit more difficult to do some of this but easily fixable I think and then you would become even more powerful and more capable alright now for our next experiment I want to measure this mysterious component and this component has TX and rx written on it and on the other side it has an antenna port so this is clearly either a diplexer or a duplexer except that we don't know which one it is and we want to measure it and find out using the RS a600 7h built-in tracking generator capability now with the tracking generator we can send signals to various ports and see what the exact frequency response of this instrument is and from that we can make some conclusions now to start I'm put it through between the two ports and this allows us to calibrate the instruments first for zero reference power and then from then we can go ahead and measure this now before I do that I want to show you a couple of settings that we can do on the signal view software to configure the tracking generator itself along with a couple of different limitations that I hope they can remove in the future okay let's go and configure the saucer to do this measurement so first up we're looking at the spectrum we already need that let's get the right window in here under the tracking generator I'm going to get a transmission game window get rid of the spectrum window here and this window is going to now give us the ability to configure the tracking here the frequency range and so on so right now it's going from 980 megahertz to one gig or just obviously very small so let's go from 1.5 gig all the way to let's say three and a half kilos and let's change the resolution manner to 1 kilo so we can get a bit more dynamic range number of points to 200 so now we're going to see this March along the way now this is not as fast as likely to be this instrument is not optimized for sweeping speed along very large frequency ranges so it can be a bit frustrating if you have to do a live measurement and and keep seeing the result as you are changing something like if you're tuning your filter but you can always change the number of points the resolution that I depending on your needs and for most of the time it would be okay so now let's find the track consider a menu and increase the power here now the highest time with these things to force is minus 3 DBM again this is ok for most things but if you have a very high loss system you're trying to measure it's going to eat into your dynamic range again so you have to just make sure that this is sufficient for your needs for active circuits obviously it's more than enough but for passive circuits it might be just a little too low but again depends on your needs and most of the time it will be fine so that of your set this up like this you can see that even without normalization you're doing pretty well this thing has a very accurate Apple power control right off the factory we are needing for any normalization but nonetheless I am I have it through so we can do normalize this circuit that gives you the temperature and the settings that you're doing it and so on so we can just bypass that perform a normalization it also gives you a couple of hints on how to improve your normalization performance and then later on the measurements you are intending to do now during a normalization it will apply a signal through the RF port and then look at it through the RF input get rid of the losses of the cables in between and make sure that you have a very flat frequency response adjust your reference and make everything ready for you to be able to do the measure that you want to perform now it's almost finished and there we go and we're done with that so now we can see very nice flat line from 1.5 you go to three and a half gigahertz two hundred point 1 kilowatt resolution bandwidth so it looks good so let's go ahead and actually change our setup so we can find out what kind of device we're looking at here we go I've removed the through line and connecting the tracking generator directly to the TX port and the antenna port is then connected to the RF input and at the same time the other export is terminated this allows me to measure the frequency response from the tracking generator to the antenna all right now that the setup is complete let's run this again and you can see that we obviously have no transmission at this frequency is going up and there is our channel look at that now if we can see clearly that from BT export to the antenna we indeed have a bandpass response and clearly high quality exactly response and then we can now see that it has very nice transmission on almost 0 DB of insertion loss at that point very good let's put a marker on this there we go so our forward transmit channel is sitting at two point four six five meters so it looks very good now now we're going to do to change the setup to see what the response is from the receive to the antenna I should say from the antenna to the receive so we have to rewire it but before we do that lets go on to traces and let's freeze this trace so it doesn't change what we're doing our next measurement as well as the fact that we can enable at phase two now phase two is still measuring the old configuration so it's going to basically overlap this measurement but no worries after it's done I'm going to just pause it so when it's completely finished is going to stop and then we're going to change your setup and do the measurement again and here I have changes set up to do the opposite measurement here I have the tracking generator connected to the antenna port and the RF input connected to the received port with the TX being terminated so this now allows me to measure the frequency response from the antenna port to the our export alright the setups change let's run this again and I'm going to do the same measurement and let's see what the RX response is and check out it's a different frequency so this is indeed another duplexer or it's a deflector allowing two different channels to be coexisting with in this module so the RX track the RX receive channel and the TX transmission are quite different from one another so this is a type lecture now the other question is once the isolation between the RX and TX now we have to change the setup again in order to do that so we're going to do the same thing we're going to go under this trace you're going to freeze this trace and we're going to create a trace 3 now and this trace 3 is going to obviously overlap the old trace again now I'm going to go change the setup and we can see the isolation between the two channels and finally the TX Rx isolation can be measured by connecting the tracking generator directly to the TX port and taking the are export and connecting it to the receiver this is a really important parameter here because you want to make sure that the transmitter doesn't leak into the receive normally you want to do this with an exceptionally high dynamic range but we're going to be limited here by the instrument but nonetheless we can see if there is any relationship between those two ports alright let's go ahead and run this again now we're going to see the isolation so so far so good and check it out is pretty good I mean it has a little bit of isolation issue over here obviously but as you can see it's doing a very good job I can reduce the resolution bandwidth even further see how slow that would be let's see if I can do half a kilo Hertz no I don't know I cannot go smaller nevermind I can't go smaller on one killer so this is the lowest we can go but I can increase the number of points now this is going to disturb my calibration but nonetheless let's double number of points we get it slightly smaller resolution steps there and let's see what happens when you hit this region obviously you can have to recalibrate this once you do this but for our purposes is okay there we go so there's definitely some activity going on real very close to the transitional point between these and that makes sense right at doing the overlap region is the most difficult part and it seems to be doing just fine and normally this overlap region has been guard bands and and so on associated with it this is a very nice symmetric response so you can see that how within from the same instrument same software you can do all these measurements at once now one thing this track in general doesn't have like this I couldn't figure out how to do is that you cannot set the tracking generator step to zero so you can't do it 0 span and normally a zero span is useful because that would allow you to use your tracking generator at this standalone synthesizer when you don't have it in any circuit like this but I cannot figure out how to do this I don't think it's capable of doing that so if I go under span and I enter 0 it goes to 1 kilowatts so that's the lowest span I can have which means that the synthesizer coming out it's going to jump back and forth within a 1 kilohertz deviation making it a little bit less useful as a standalone synthesizer so I think it's something that can easily be changed if they want to use this as a standalone synthesized that they should be able to do that and I hope that they make this change as well because it would be pretty useful so one of the great advantages of this instrument with regards to its tracking generator is that it can measure return loss and distance to failure as well as VSWR without needing any external coupler so you only need this one port to do this measurement and you can calibrate this port like you would do with a one port network analyzer it's going to do a scaler measurement but you can do a short open and a load and then you can do all of your return loss measurements directly from this port with no other component which is fantastic it's already a huge advantage compared to the competitors that require the external a coupler it makes it a lot easier to use especially in the battery-powered version and that's obviously what they've done that because you want to be able to use this on the field without having to use anything else so let's go and take a look and see how that performs I'm interested in measuring my tunable microwave filter and I want to see its return loss as a function of its center frequency so you obviously expect this return us to line up with center frequency so let's see how that performs I've terminated one end of the filter and the other end I'm going to connect directly to this and we should be able to do our measuring but first we have to of course configure the software do our calibration and make sure that it is up and running right let's prepare the software so let's go ahead and get the right window from the return loss window here so we can do cable loss or return loss or distance to failure measurements now I'm not going to go to every single thing for the interest of time but I recommend that you look at this for our purposes let's look at the return loss and get through the spectrum but the cable loss is also extremely useful by looking at the loss of the return signal you can compute the loss of the cable and so on I'm going to leave that for some other time so let's go ahead and take a look and see what this one that looks like now for return loss and distance to a failure measurement you obviously need to do calibration in order to be able to create a reference plane at the edge of the cable you want to measure let's change the frequency let's look at the wider frequency let's go from one gig and all the way to let's say 4 gig or gigahertz now let's increase the number of points to 500 on one so this is our setting you can see right now I'm connected to an open basically and it's uncalibrated so you're getting essentially almost 0 DB for the return loss measurement it's going to calibrate you now for the calibration you can use the factory calibration or user calibration let's do a new user calibration they're all the settings that are already here the calicut parameters can all be answered so it's a full-fledged calibrate there's no shortcuts here but I'm not going to answer these parameters here because first of all I don't know exactly what they are from my calibration kit and for our purposes we really don't need to worry about that so let's do it off in calibration here I already have an open connected so it's going to go measure that similarly luck it as you would with the metric Allah accepts doing scalar measurements that let's go ahead and now do a short and for a short we're going to do exactly the same thing and do a measurement there we go connect it and a short measurement there so now I'm going to see that as well and as soon as it's finished I'm going to do a load calibration here we go there's our 50 ohm that's not a load there is a 50 ohm load right here and you can already see that we see the classic response over there we're going to measure that and it's going to look good once it's done there is there is our calibration now it's applied and it's sitting below minus 40 because I'm turning it into a low so if I go let's say minus 80 I should be able to see it there it is so we are sitting really long below minus 60 62 DB return loss so we have a pretty good calibration so let's go and disconnect that as soon as I disconnect load we're going to jump right back up there and I'm going to connect it to my filter there's it I'm going to set the filter to two and a half to go and check it out so I returned that it's right around here and then as soon as we hit as soon as and this is a little bit misleading I should put it at 10 so that you can see the zero line because it was sitting at 9v be per division there it is so we hit this right over here this is the center frequency of the filter you can see how well match to this goes all the way down to minus 30 and outside it's back all the way up back to zero DB and there's a little bit of ripple here so if I put a marker it's going to put it to the peak it should also have a marker to minimum there you go there it is so you can see our center frequency right now we are sitting at two point five one eight giggles there it is so this is correct I can change the center frequency it's running in the background so let's go all the way to a little bit higher frequency that's sweeping I can't tell where it is there it is it would be nice if it had a little point showed you where the sleep was actually taking place so you could see a third eye just move it forward I can go all the way down to below two and a half degrees so in the next sweep I should catch that there it is there we go so you can see that you will be able to follow it there if it was doing a little bit a better job at drawing it but yeah so you can see how easy it works and there's actually another window you can take a look at so if I go under here you can configure your distance to fail your measurements put all the parameters and then then you find out where the cable is failed now this sitting at the bench it may not seem very useful but for the battery powered version of this instrument when you're outside in the field and this is very very handy and you can change the display you can display the return loss or distance to failure you can to VSWR it has the full sized soft I can see that it is still being developed because some of the little features are still being added which is great and some of the comments I made earlier are the one that I'm hoping they would add to this and these are small changes that will make a big difference in the way the users able to take advantage of especially the ability to do 0 I get a zero hour span to give to be able to use the generator as a synthesizer I mean this is a seven and a half bigger synthesizer at your desk you would want to be able to use and it makes this instrument much more useful yeah so I think this would be a pretty interesting tool as well and there you have it the full review of the Tektronix RSA 607 a that I hope you enjoyed this is a really competitive instrument especially at this price point I cannot think of anything else on the market right now that can do as much as this at this price so I definitely encourage you take a look and see if it works for you and if it fits in your workflow now there are several ways you can support my channel first you can of course leave a comment subscribe to it give it a thumbs up and that way the video will have a reach a larger audience the other way is to support my patreon channel and the people who have been supporting my patreon channel have been amazing because of their support I am able to you know upgrade my camera I have new audio equipment and I'm also able to purchase new equipment from eBay to do more repair videos which is something that I know you guys really really enjoy the other way you can help me is to contact the manufacturers and let them know that you enjoy these reviews or that they are partially responsible for your design to buy one of the requirement I get no fun no money from the sale of these instruments but it helps me to have a good relationship with them and to be able to bring you sterile yard instrument as they come onto the market and review them for you so I hope you enjoyed this and I'll see you in the comment section

Channel: The Signal Path

Views: 23,530

Keywords: Spectrum Analyzer, Real-Time, FSK, Frequency Hopping, Spread-Spectrum, Modulation, Tracking Generator, Return Loss, Distance to Failure, DTF, Cable Loss, SignalVu, Teardown, Synthesizer, SAW Filter, Tunable Filter, Microwave, ADC

Id: CFQxqZcWGHg

Length: 54min 38sec (3278 seconds)

Published: Sun May 28 2017