[time-nuts] OT: Spectrum Analyzer
didier at cox.net
Sat Oct 31 21:08:30 UTC 2009
Another major difference between the older (sweeping) analyzers and the more modern ones (FFT) is that the sweep type analyzers only look at one particular frequency once per sweep, and for a short time, while the fft types pretty much look at the entire span continuously. That makes the fft type much more capable of identifying low duty cycle transmitters. If the signals you are interested in are CW, it will not make much difference, but that is not always the case.
------------------------ Sent from my BlackBerry Wireless thingy while I do other things...
From: Brooke Clarke <brooke at pacific.net>
Date: Sat, 31 Oct 2009 13:03:29
To: Discussion of precise time and frequency measurement<time-nuts at febo.com>
Subject: Re: [time-nuts] OT: Spectrum Analyzer
Spectrum analyzers can be used in different ways. For example if you know
there's a signal and want to characterize it. The other case is where you're
looking for some unknown signal that may be (or may not be present) down near
the noise threshold.
The first case is straight forward and any of the modern analyzers will do a
good job. In the search case analyzers like the HP 70,000 series or the 4395A,
4396A/B can search orders of magnitude faster than conventional units.
Note that the 4395A uses a 12 MHz wide analog IF feeding a fast DSP based
receiver. This allows things like a real 1 Hz IF bandwidth and also allows
real power [SQRT(I^2 + Q^2) detection]. All analog SAs use peak detection
since they have no way of detecting power.
Brent Gordon wrote:
> I'm thinking of buying a spectrum analyzer and would like to know what
> Time Nuts recommend. My requirements are fairly simple:
> 3GHz Max frequency or higher
> Either GPIB or Ethernet interface for control and data capture
> Not much larger than an average desktop computer. Portable is nice but
> not necessary.
> Preferably under $3000.
> I thought about building Scotty's Spectrum Analyzer or Poor Man's
> Spectrum Analyzer, but decided I would rather buy one then build one.
> I have an HP 141T but I am looking for something more modern. One of my
> uses will be looking at C and Ku band satellite signals (down converted
> to 950-2050 MHz). I'll also be using it to look at various RF data
> links from 433 MHz to 2.4 GHz.
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to
> and follow the instructions there.
time-nuts mailing list -- time-nuts at febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
More information about the time-nuts