Bruce Griffiths bruce.griffiths@xtra.co.nz said:

What would a suitable board look like and/or what sort of gear do you need to
measure PN?

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These are my opinions.  I hate spam.

Hi

The “best” way to measure phase noise will always be a “that depends” sort of thing. One
pretty darn good way to check noise on any amplifier is to use something like a TimePod.
You use a power splitter and a pretty good source. First you check your TImePod (or whatever)
for floor. You then stick the amp in one leg. You re-measure phase noise (or ADEV). Assuming
it comes up above the previous floor, you have your number for the device. If it does not come
up above the previous floor, you need a different test set.

Bob

Since I have a Timepod all that I'd need would be a board that had SMA inputs and outputs with provision for an LC L network to  step up the input if necessary plus an RLC network on the output something like in the attachment.

If one doesnt have a Timepod or equivalent a low noise phase detector will suffice for the noisier sources. An adjustable phase shift network is required to achieve quadrature between the LO (driven directly from the splitter) and the RF input (driven by the DUT output).

The required phase shift adjustment range could perhaps be reduced by using a quadrature hybrid to split the test source instead of a standard splitter. The output of the phase detector is low pass filtered and amplified and fed to a high resolution ADC such as a sound card.

Bruce

Hi

Having tried to do these measurements a lot of ways ….. the TimePod makes it very
easy. The ability to get phase noise and ADEV “all at once” is part of it. The ability to
handle a wide range of input levels with minimal degradation is a also part of the why.
The software makes it easy for lazy Bob … a big plus ….

Bob

BruceWisjh I had known about it a week ago and we could have added a board to the A9 order. Next order is probably three weeks away ifIi can help contact me off list     Bert Kehren
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-------- Original message --------From: Bruce Griffiths bruce.griffiths@xtra.co.nz Date: 3/4/18  8:32 PM  (GMT-05:00) To: Hal Murray hmurray@megapathdsl.net, Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] LT1016 as a pulse shaper...
Since I have a Timepod all that I'd need would be a board that had SMA inputs and outputs with provision for an LC L network to  step up the input if necessary plus an RLC network on the output something like in the attachment.

If one doesnt have a Timepod or equivalent a low noise phase detector will suffice for the noisier sources. An adjustable phase shift network is required to achieve quadrature between the LO (driven directly from the splitter) and the RF input (driven by the DUT output).

The required phase shift adjustment range could perhaps be reduced by using a quadrature hybrid to split the test source instead of a standard splitter. The output of the phase detector is low pass filtered and amplified and fed to a high resolution ADC such as a sound card.

Bruce

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