Fabio FZ Posted October 29, 2020 Share Posted October 29, 2020 How can I measure DUT delay ? Link to comment Share on other sites More sharing options...
attila Posted October 29, 2020 Share Posted October 29, 2020 Hi @Fabio FZ You can find phase measurement in Network Analyzer, Custom Global Measurement in Scope or in latest beta version phase is available in Scope/FFT view and Spectrum Analyzer. https://forum.digilentinc.com/topic/8908-waveforms-beta-download/ Link to comment Share on other sites More sharing options...
Fabio FZ Posted November 6, 2020 Author Share Posted November 6, 2020 Thanks, that was helpful, but still I am missing how to measure and input the DUT delay compensation otherwise measuring the phase response of a digital device that have a propagation delay would me misleading like the below. Link to comment Share on other sites More sharing options...
attila Posted November 7, 2020 Share Posted November 7, 2020 Hi @Fabio FZ Could you provide more detail about the experiment setup? software and hardware... You can inspect the captured signals under View/ Time. Your signal may be distorted by exceeding the Wavegen current limits, your circuit may need longer settle time for each step.... Link to comment Share on other sites More sharing options...
xc6lx45 Posted November 8, 2020 Share Posted November 8, 2020 Actually I'm wondering what you consider "misleading" about your result. This is what a network analyzer will show when you set it up as you did. Some thoughts: - use a linear frequency axis instead of logarithmic (and a linear frequency sweep, at least on a conventional CW-swept VNA) - you need a higher density of points so the eye can unwrap the phase in the 6 kHz region (for an algorithm this might be even enough but it's visually distracting). Right now, it looks like the direction changes but that's a visual artifact from connecting the dots within a single 360-degree zone. Link to comment Share on other sites More sharing options...
Fabio FZ Posted November 9, 2020 Author Share Posted November 9, 2020 Thanks Attila , I am measuring a DSP that have a 2ms latency ( propagation delay ) - I what to check the output phase of this DSP using the input as a reference . Due to the DUT ( DSP ) delay the phase isn't correct and the results are what I would expect . On other types of measuring system I am able to measure this latency and compensate on the software for example Rgsd Fabio Link to comment Share on other sites More sharing options...
Fabio FZ Posted November 9, 2020 Author Share Posted November 9, 2020 On 11/8/2020 at 5:32 AM, xc6lx45 said: Actually I'm wondering what you consider "misleading" about your result. This is what a network analyzer will show when you set it up as you did. Some thoughts: - use a linear frequency axis instead of logarithmic (and a linear frequency sweep, at least on a conventional CW-swept VNA) - you need a higher density of points so the eye can unwrap the phase in the 6 kHz region (for an algorithm this might be even enough but it's visually distracting). Right now, it looks like the direction changes but that's a visual artifact from connecting the dots within a single 360-degree zone. Thanks xc6lx45 - you are correct , using more points will sort out the phase artifact -but on this case I am looking to see the a flat phase curve by compensating the DUT latency ( I am measuring in to out phase ) Link to comment Share on other sites More sharing options...
xc6lx45 Posted November 10, 2020 Share Posted November 10, 2020 OK I think I got your point. You want to zero out some baseline delay with a phase that's linear with frequency. On a RF VNA the feature would be labeled "electrical length correction" or the like, if that's of any use to locate the parameter. Link to comment Share on other sites More sharing options...
Fabio FZ Posted November 11, 2020 Author Share Posted November 11, 2020 Yes you got it - It seems that te feature is not avaliable on AD2 - Hope that I am wrong as this is very useful tool and all major measuring systems have it. Link to comment Share on other sites More sharing options...
attila Posted November 11, 2020 Share Posted November 11, 2020 Hi @xc6lx45 @Fabio FZ Is this "electrical length correction" expressed in time? I think I can add such option to the NA. Link to comment Share on other sites More sharing options...
attila Posted November 11, 2020 Share Posted November 11, 2020 Hi @Fabio FZ You can find the latest beta with NA Phase Compensation option here:https://forum.digilentinc.com/topic/8908-waveforms-beta-download/ Does this help your measurement? Link to comment Share on other sites More sharing options...
xc6lx45 Posted November 12, 2020 Share Posted November 12, 2020 On 11/11/2020 at 5:59 PM, attila said: Hi @xc6lx45 @Fabio FZ Is this "electrical length correction" expressed in time? I think I can add such option to the NA. Yes, it's just a roundabout way to express it via the speed of light (usually with the effective epsilon_r of the dielectric as extra parameter, then it's really a physical line length). For AD frequency range, using time seems a good choice, IMHO. For example, taking a random Rohde manual: https://cdn.rohde-schwarz.com/pws/dl_downloads/dl_common_library/dl_manuals/gb_1/z/zvl_1/ZVL_Operating_en_09.pdf Page 137 "Phase Delay/El. Length" Link to comment Share on other sites More sharing options...
Question
Fabio FZ
How can I measure DUT delay ?
Link to comment
Share on other sites
11 answers to this question
Recommended Posts
Archived
This topic is now archived and is closed to further replies.