[time-nuts] New 10 MHz Distribution Amplifier

BNeubig at t-online.de BNeubig at t-online.de
Fri Aug 15 06:56:07 EDT 2008

Hello Martyn,

Martyn Smith <martyn at ptsyst.com> wrote:
Despite the AGC we still achieve good phase noise (-135 dBc/Hz @ 1 Hz
a -168 dBc noise floor) together with 130 dB isolation and 10 ps/C phase

I have problems to understand, how your amplifier can achieve phase
noise of -135 dBc/Hz @ 1 Hz. Such a dBc/Hz measure is related to a
carrier, but where does the carrier in your amp come from?
The same applies to the graph in your data sheet. This obviously shows
the phase noise of an oscillator, which feeds your distribution
amplifier, not the inherent noise of the amplifier. It needs a different
measurement technique to characterize the inherent noise of an
amplifier, and there are different numbers to come out of that.
At this point I am not able to argue about the -135 dBc/Hz @ 1 Hz for
your OCXO, as you do not specify, what model and brand that is.


Bernd Neubig

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