[time-nuts] 35601A as stand-in for 11848A ?

John Miles jmiles at pop.net
Sun Jan 6 17:58:38 EST 2008


So, I guess the main question is, in the absence of something like the
85671A package or mine, how _exactly_ are you turning the dBc/Hz values you
get from (say) the 8561E into your ~-120 dBc/Hz numbers?  Let's hear the
step-by-step procedure on that, and the problem should reveal itself.

One good thing is that these measurements are generally not limited by the
SA's signal-to-noise ratio, either RF noise or LO noise.  The LNA overcomes
the RF noise figure, and the carrier suppression associated with the
baseband conversion takes reciprocal mixing off the table.

-- john, KE5FX

> -----Original Message-----
> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com]On
> Behalf Of SAIDJACK at aol.com
> Sent: Sunday, January 06, 2008 2:33 PM
> To: time-nuts at febo.com
> Subject: Re: [time-nuts] 35601A as stand-in for 11848A ?
>
>
>
>
> In a message dated 1/5/2008 16:31:23 Pacific Standard Time,
> jmiles at pop.net
> writes:
>
> >Are  you using my PN software, or your own?  If it's mine, what are  you
> >plugging into the "Noise Response" field?
>
> >-- john,  KE5FX
> Hi John,
>
> I am running this on two instruments: an Audio Precision II Audio
>  analyzer
> (in FFT mode) and an Agilent 8561E. The 8561E has a lower limit
> of  about 30Hz,
> so that unit is a bit limited. It's signal to noise ratio is also  not as
> good as the APII system. The AP FFT analyzer is limited to ~20KHz
> offsets
> though, which is OK I am mostly interested in the PN <10KHz.
>
> bye,
> Said
>
>
>




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