EEVblog Electronics Community Forum
Products => Test Equipment => Topic started by: ralphd on July 15, 2015, 02:20:32 am
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I did some testing and found the hardware frequency counter to have an error of less than 2ppm. Pretty good for something I didn't even know I was getting when I bought it!
http://nerdralph.blogspot.ca/2015/07/rigol-ds1054z-frequency-counter-accuracy.html (http://nerdralph.blogspot.ca/2015/07/rigol-ds1054z-frequency-counter-accuracy.html)
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Thanks for posting your research! Good to know...
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My 1054z is off by about 5pp, still not too bad.
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Interesting. I've got an older 1052E, and it has a roughly similar hardware frequency counter. It's worth emphasizing that the hardware frequency counter on virtually any digital scope is several orders of magnitude better than the frequency displayed by the "measure" function. That hardware frequency counter is a nice bonus feature. If anyone wasn't aware of it, play with it!
I'm a ham radio operator. My best HF radio has a TCXO to generate its reference frequency, and I have calibrated that radio using the NIST radio station WWV, which broadcasts precisely on 10.000 000 MHz. The biggest source of error in that calibration is that the propagation path through the ionosphere has a somewhat variable delay, but it's more than good enough for my purposes. Anyway, immediately after calibrating the radio to WWV, I tried measuring its frequency using the DS1052E. I've forgotten exactly how far off the measurement was, but I think it was in the 10s of Hz for a frequency just over 10 MHz -- IOW, something on the order of a couple of ppm. I wasn't being too scientific and writing everything down. I'll have to repeat the test one day, being more careful, and maybe trying it at different temperatures.
Another interesting game I have played with that hardware frequency counter is to set it up for AC triggering and precisely measure the frequency of the mains power. No probe needed! Why do I care what the frequency is? Well, I don't care very much, but it's mildly interesting to compare my measured frequency with the frequency as displayed here:
http://fnetpublic.utk.edu/gradientmap.html (http://fnetpublic.utk.edu/gradientmap.html)
That shows a map of the frequencies of the power grids in the USA, updated in near-real-time. I find that my own measurements with the oscilloscope correlate pretty well with the fluctuations shown on that map. It was a "WOW" moment when I found that site and made my own measurements that correlated with it. Not that it's exactly useful to me, but...