[time-nuts] time-nuts Digest, Vol 99, Issue 120

[Bill Fuqua]

There are two ways to measure the carrier frequency using a Spectrum analyzer.
1)  have bandwidth sufficient to capture all the sidebands produced
by the FM signal.
2)  Have your bandwidth set very narrow, 10Hz or so and tune it directly
on the carrier frequency. The carrier frequency should stand out at the
wide bandwidth and then zoom in on it when using the spectrum analyzer.

There are situations with PSK signals where the carrier is always
canceled out. As there are certain modulation indexes when a pure tone
is being used where the carrier goes to zero. But with music or voice
modulation this will not be a problem.

   I have notices that only one digital TV station here in Lexington KY is
right on. Some are hundreds of Hz off.

73
Bill wa4lav


At 12:00 PM 10/27/2012 +0000, you wrote:

>From: Peter Gottlieb <nerd at verizon.net>
>
>
>I've used the HP 3586 for measuring AM carrier frequencies as well as my Tek
>495P (both referenced to Rb) for higher frequencies such as air band.
>
>Some carriers are dead nuts on while others are quite far off (at least to my
>mind) although I've never found one outside of its required tolerance.
>
>It seems possible to measure pretty accurately with these instruments, at 
>least
>on AM or CW signals, but not sure the best way for FM.  I've played with 
>the HP
>53310A but haven't set it up for precise measurements yet, or really studied
>what all it is capable of.