MSO44 scope issue getting average freq

Please see attached pic &quot;multi cycle&quot;. The pulses bounce around a bit but the periods center around 500 us, which should translate to 2 kHz avg but the badge gives me 20+MHz average frequency.&#160;<br> I have also included a pic zooming in on one pulse.&#160;<br> How do I configure the scope to give me more accurate stats?&#160;

Hi Xiang,<br> <br> It's unclear which channel your measurement is working on, but I will assume it's channel 2.<br> The problem is that there are different frequencies in your signal depending how you measure it. You have to be clear about what you want to measure by manually setting the reference levels in the measurement configuration tab, preferably to absolute levels.

The badge was yellow so chan1.&#160;<br> I have set the abs levels and it definitely helped. I now see expected freq stats.&#160;<br> One more question about the low level.&#160;<br> See attached pic. you can see the min of the trace is 233 mV which is quite a bit higher than the &quot;low&quot; that i have set (-1 mV) so how come it's still able to give me accurate frequency stats?&#160;<br> What I'm expecting is that the freq badge should give me empty value until I raise the &quot;low&quot; of the abs ref level to around 250 mV (higher than 233 mV so it triggers).&#160;<br> Doesn't the waveform have to cross &quot;low&quot; AND &quot;mid&quot; AND &quot;high&quot; to be counted as one cycle?&#160;<br> I'm using AND in the sense of logic &quot;and&quot; meaning that all 3 have to be satisfied at the same time.&#160;

<p>Hi Xiang,</p> <p></p> <p>My bad, the channel 1 badge is right there, of course it's a channel 1 measurement.</p> <p></p> <p>From my testing, the frequency (and period) measurements only use the mid level and hysteresis, the high and low level don't seem to affect it.</p>

Afonso is correct.&#160; Our frequency measurement sits on top of an edge extractor that runs an edge extraction pass on input waveforms at the mref value.&#160; (It does not look at HREF or LREF and while it might give you warnings, it will even attempt to report frequencies if you drive the signal off screen both high and low).<br> <br> The edge exctractor requires the input signal transition completely through the hystersis band (top to bottom or bottom to top) and will then do a siinc-interp location back to the appropriate location of the edge crossing, potentially between samples.<br> <br> The resulting edge vector is processed to report every frequency seen on the input vector.&#160; &#160; (just running through the edge list).&#160; &#160;(Those generate 'current acq' stats).&#160; &#160;multi waveform passes then generate 'multi acq measurement stats').. using every edge we've seen.<br> <br> Note that waveforms with large idle periods may cause confusing results depending on the nature of the crossing...&#160; &#160;(e.g. a signal might be 0 level for a long period, but the edge extractor will still put an edge in the middle provided it passed through the hysteresis band).<br> <br> If you want to avoid potential confusion for such waveforms, it can be worth using gating to eliminate said areas.&#160; &#160;(cursor gating, logic gating the measurement would both work)<br> &#160;