[time-nuts] Phase noise measurement (was - no subject)
bruce.griffiths at xtra.co.nz
Sat Aug 21 19:47:13 UTC 2010
EWKehren at aol.com wrote:
> Thanks Bert
> In a message dated 8/21/2010 11:43:53 A.M. Eastern Daylight Time,
> dk4xp at arcor.de writes:
>> Wenzel Audio Amp referred to in this email. Perfect! I drive with it a
>> 3561A and a 7L5! Works for me. The only problem is getting any more
>> Any recommendations?
> NXP BF862, available from digi-key.
Don't these devices have relatively high flicker noise?
> I have used it in a similar hookup with good success. Its virtue is the
> low noise voltage AND low input capacitance at the same time.
> You could deploy MANY of them in parallel until you get
> into the capacitance range of a single Interfet device.
The input capacitance is relatively noncritical in this application
(phase noise measurement) since it is shunted by the much larger output
capacitance of the low pass filter at the mixer IF port.
> One heroic effort for audio is here:
> http://www.diy-audio-engineering.org/index.php?board=2.0 HPS5.1
> I currently use 3 pairs of SSM2210 in front of a AD797.
> regards, Gerhard
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