[time-nuts] Stepping up the output of an OCXO

[John Ackermann N8UR]

Dr Bruce Griffiths said the following on 02/02/2007 06:29 PM:

> Since the MAX477 has an input noise of around 5nV/rtHz at 10MHz compared 
> to around 1nV/rtHz for a low noise bipolar transistor, the MAX477 may be 
> expected to be have a phase noise floor of up to 14dB higher than that 
> of an optimised discrete transistor amplifier. This however may not be a 
> concern unless one has an OCXO with a phase noise floor approaching the 
> state of the art (-180dBc/Hz).

I had a chance to measure a TADD-1 using an HP-3048 phase noise system
last year.  I've attached a screen shot of the results; in short it was
below -140dBc/Hz from 100 Hz on out (by the way, I'm not sure I would
trust the noise floor shown in this test; I am not certain we had the
best test set-up).  That's within a few dB of what HP said their 5087A
amplifier would do.

I'll soon have access to a new phase noise measurement system and will
relook at the TADD-1 performance with it.

John

-------------- next part --------------
A non-text attachment was scrubbed...
Name: TADD-1_Residual_PN_at_10MHz.png
Type: image/png
Size: 4587 bytes
Desc: not available
URL: <http://febo.com/pipermail/time-nuts_lists.febo.com/attachments/20070203/b5a8e439/attachment.png>