[time-nuts] Any simple way to get 200 MHz from 10 MHz?

Dr. David Kirkby (Kirkby Microwave Ltd) drkirkby at kirkbymicrowave.co.uk
Sun Sep 28 07:23:56 EDT 2014

On 28 Sep 2014 11:37, "Poul-Henning Kamp" <phk at phk.freebsd.dk> wrote:
> There's a pretty excellent 10->200 MHz multiplier in your HP5370.
> Consider using it for an experiment to see if your idea even works...

I know longer have that - I sold it to someone on this list, then later
regretted selling it!

But I do have a signal generator to test the idea.

I must admit I am not 100% confident I can make it work - at least not in a
way I can get all 4 S parameters.

I think it is relatively easy if you have access to several internal
signals in the VNA, but not so easy if the VNA has a built in test set, and
no access to the switch or directed access to the receivers. There are
commercially available extenders that make a 30 GHz VNA work at 1 THz or
more,  but these require access to certain signals I don't have.

I was for example thinking of using photo diodes to detect the position of
the test set, as there's a couple of LEDs on the front panel which indicate
whether the souce is routed to port 1 or 2. Another possibility is perhaps
sensing the RF power,  but that could be tricky as one doesn't know what
direction it is flowing. One would with a very high directivity coupler,
but I don't think that is practical.  The source in the VNA can be set as
low was -40 dBm, but a DUT could inject +20 dBm into the port. The damage
threshold is +30 dBm. So I don't see an easy way of knowing which port is
energised. Sticking light sensors near LEDs is not very elegant, but I
can't think of a better way!

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