[volt-nuts] Practical power supply noise testing
brooke at pacific.net
Fri Jul 1 17:39:41 EDT 2016
When testing VCOs any noise on the control voltage causes a frequency change in the output which can be characterized.
The HP/Agilent 4352 VCO tester contains a programmable DC supply with exceptionally low noise.
Instead of headphones something like the HP 4395A which has a spectrum analyzer mode with a true RBW of 1 Hz to allow
displaying root(Hz) noise levels (true I&Q detection rather than the old analog peak detection).
AFAICR there were some HP app notes on measuring power supplies which may have included noise.
The lesser of evils is still evil.
-------- Original Message --------
> In message <2656F010-8E12-4BAD-B9AE-713CEFEE1B0A at febo.com>, John Ackermann N8UR writes:
>> I have several supposedly low noise bench power supplies that I want to check out. They seem to work well but are quite old, so of course one wonders about the caps, etc.
>> Can someone suggest a practical test regime to verify power supply
>> DC noise performance? Preferably one that doesn't require building
>> up custom low noise amps?
> Listen to them ?
> All the "hard" noise is in the audio-range, so a series capacitor
> a low-noise amp and a pair of headphones...
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