Keysight B2962A power source generating clean sine waves? - Page 1
Forum section: electronics / testgear

author: maxwell3e10
author_rank: Frequent Contributor
timestamp: December 04, 2019, 03:35:31 am
content: Does anyone have a Keysight B2961A/B2962A power source? I am curious how well it works, in particular for making sine waves?In principle, it should have high dynamic range corresponding to 6 digits of vertical resolution. But the time sampling is relatively slow, 100 kS/sec. So I am curious how clean a 1 kHz sine wave would be on a spectrum analyzer?

author: Someone
author_rank: Super Contributor
timestamp: December 04, 2019, 06:11:12 am
content: Its comparable to the built in 10bit wavegen on their scopes as a signal/voltage source, but with significant roll off in noise above 50kHz. Varying settling times for the many possible combinations of voltage and current ranges don't have significant effects at those low frequencies when driven into trivial resistive loads.

author: maxwell3e10
author_rank: Frequent Contributor
timestamp: December 04, 2019, 02:10:30 pm
content: So someone does have a B2961A! It should be better than a 10 bit generator if it really uses the full dynamic range and doesn't have too much time jitter. They make a big deal about various filters, but OK, one can always add a filter to any generator. The question is how clean is the signal in the 1Hz-1kHz band.

author: egonotto
author_rank: Super Contributor
timestamp: December 04, 2019, 06:37:27 pm
content: Hello,in datasheet:"Arbitrary Waveform Generation Capabilities....THDVoltage Source -90 dB 3 , Current Source -90 dB 4...3. ±1 V, ±10 V, ±180 V, open load4. ±1 uA 100 kΩ load, ±10 uA 100 kΩ load, ±10 mA 100 Ω load"Best regardsegonotto

author: maxwell3e10
author_rank: Frequent Contributor
timestamp: December 04, 2019, 07:37:52 pm
content: Yes, that's not bad, but not as good as a low distortion audio generator (<100dB). I guess the king in this area is the Audio Precision APx555, -120dBThe advantage of B2962 is that it can drive higher currents, but the spec only refers to fairly small currents, is it too conservative?

author: Someone
author_rank: Super Contributor
timestamp: December 04, 2019, 11:28:17 pm
content: Quote from: maxwell3e10 on December 04, 2019, 07:37:52 pmIt does not achieve those specifications for general signals, your requested example of a 1kHz sine ends up with the harmonics at 60-65dBc when using their inbuilt waveform.

author: maxwell3e10
author_rank: Frequent Contributor
timestamp: December 04, 2019, 11:46:03 pm
content: Interesting. So its not only not conservative, but is actually worse than the specs?! What current were you using? Thanks for doing the test.

author: Someone
author_rank: Super Contributor
timestamp: December 05, 2019, 12:02:15 am
content: Quote from: maxwell3e10 on December 04, 2019, 11:46:03 pmThere are probably some specific frequencies and conditions under which it will achieve the banner figure, but I have no idea what they are. When so many audio specifications are based around a 1kHz test tone that performance is what's interesting in those applications. Current ranges of 1mA, 10mA, 100mA, or 1A or signal amplitude didn't change the result significantly, frequency had more effect.