Fabio FZ 0 Posted October 29, 2020 Share Posted October 29, 2020 How can I measure DUT delay ? Link to post Share on other sites
0 attila 487 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 post Share on other sites
0 Fabio FZ 0 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 post Share on other sites
0 attila 487 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 post Share on other sites
0 xc6lx45 166 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 post Share on other sites
0 Fabio FZ 0 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 post Share on other sites
0 Fabio FZ 0 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 post Share on other sites
0 xc6lx45 166 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. attila 1 Link to post Share on other sites
0 Fabio FZ 0 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 post Share on other sites
0 attila 487 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 post Share on other sites
0 attila 487 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 post Share on other sites
0 xc6lx45 166 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" attila 1 Link to post Share on other sites
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Fabio FZ 0
How can I measure DUT delay ?
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