Recent content by Moto

@pkane I was just talking to matt at quantasylum as I was having an issue using a qa402 to do a stepped sine frequency sweep of a dac checking for linearity. He suggested using a fiat top window because he uses peak instead of rms values in measurement for the following reason. I never had an...

How did I forget that! Thx

I must be having brain fog, but how do I get a stepped sine sweep of dbfs input level to the adc vs frequency? Thx for any help. Any thoughts?

This is one, but there are a couple before it that speak to the general issue. Post in thread 'Topping E30 II Lite DAC review and measurements' https://audiosciencereview.com/forum/index.php?threads/topping-e30-ii-lite-dac-review-and-measurements.47518/post-1704639

Thread 'Topping E30 II Lite DAC review and measurements' https://audiosciencereview.com/forum/index.php?threads/topping-e30-ii-lite-dac-review-and-measurements.47518/ @pkane there is some discussion near the end of this thread about your software and the way it treats multitone tests in the...

@Rja4000 what does your new 600 ohm load look like?

@pkane you are the best!

@pkane I was just wondering if max harmonics could default to the highest number of harmonics in the measurement range. Whenever I increase a measurement range, I often forget to increase the harmonics to get the correct thd in the display panel.

I had just realized that and edited the post to delete that but you beat me to it with an answer!

Interesting. Then REW and Multitone should agree on snr. Odd that snr in Multitone is about 2db better than REW. Oh well.

Maybe I misunderstood you earlier. I thought you said in the snr calculation that you used noise plus harmonics in the “noise” part of your computation.

@pkane does it make sense that snr in Multitone would be better than snr in REW given john’s clarification of REW’s computation of snr?

Thx @JohnPM . So snr=-N always in REW in dbc mode? It seems like snr in REW should always be better in REW than in Multitone since Multitone includes all harmonics in N. The opposite is true though. Multitone always shows higher snr than REW.

I’m sorry to be dense, but in Multitone, why do I see e.g., snr=124.8 and thd+n=-122.8 when all harmonics and noise are included in the snr? Why isn’t snr just the negation of thd+n? In the latest beta of REW, snr=-N which is a few 10ths of a db better than thd+n. That seems to violate john’s...

@pkane so snr is computed in multitone using all noise and all harmonics in selected measurement range, not just max 15 harmonics plus noise? It also does just the measurement range, not nyquist/2?