[time-nuts] 5120A and PM singal

[John Miles]

Remember that any instrument that displays phase noise as ℒ(f) is subject to the small-angle constraint, and that includes the 5120A and other gear in its category.   Any amount of PM that shows up at -26 dBc/Hz at 10 kHz is definitely not a "small angle" effect.   See page 40-43 of http://cp.literature.agilent.com/litweb/pdf/N9068-90005.pdf , for example.

-- john
Miles Design LLC


> -----Original Message-----
> From: time-nuts-bounces at febo.com [mailto:time-nuts-
> bounces at febo.com] On Behalf Of Azelio Boriani
> Sent: Monday, January 14, 2013 7:33 AM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] 5120A and PM singal
> 
> Should the peak level be at 10MHz? Why 10KHz? 10KHz is the delta from the
> carrier: 10MHz plus or minus 10KHz. Moreover, 1Hz is 2*pi*Rad, 1Rad should
> be 1Hz/(2*pi).
> 
> On Mon, Jan 14, 2013 at 11:35 AM, Filip Amator
> <filip.amator at gmail.com>wrote:
> 
> > Hello,
> >
> > I made a simple measurement using Symmetricon 5120A phase noise
> > measurement set and a Marconi 2024 signal generator and I don't
> > understand the results. I measured the phase noise of 10 MHz signal
> > with 1 Rad phase modulation at 10 kHz, and I got from mesurement peak
> > at 10 kHz with level about -26dBc/Hz. According to the current
> > definition of dBc/Hz, the value of -26dBc/Hz should be considered as a
> > -26dB of modulation relative to 1 Rad. But I would expect that the
> > peak level will be at 0 dBc at 10 kHz. Does anyone knows how to
> > explain this difference?
> >
> >
> > Filip Ozimek
> >
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