Return to KLUBNL.PL main page

rsgb_lf_group
[Top] [All Lists]

Re: LF: DL2NDO/P (-> noise level estimation)

To: [email protected]
Subject: Re: LF: DL2NDO/P (-> noise level estimation)
From: [email protected]
Date: Wed, 24 Jul 2002 17:09:45 EDT
Reply-to: [email protected]
Sender: <[email protected]>
Hello Jim and group,

>> You could also do a similar calculation using SpecLab to calibrate the
signal level - here you have to take care not to adjust the RX gain (and
keep the AGC turned off) between calibrating and measuring. To interpret
the noise level you would have to take the bandwidth/resolution settings
into account.
<<

Agreed, if you are using the function "noise(f1,f2)" to do this. It returns the noise level as seen on the waterfall/spectrum, so it depends on the frequency resolution (or, in other words, the decimation- and FFT-gain). But there is another function noise_n(..) which does basically the same, but normalizes the noise level for a 1-Hz-RX bandwidth, taking the FFT bin width into account.
Be aware to set the frequency range in which the noise is measured away from the edges of the IF filter's edge, and don't make the observed frequency range too narrow. You may find yourself observing the noisy slopes of hard-keyed (clicking) CW signals, etc....
By the way - the noise( ) - function is is based on an algorithm described by Andy 'JNT.

Regards,
Wolf DL4YHF
<Prev in Thread] Current Thread [Next in Thread>
  • Re: LF: DL2NDO/P (-> noise level estimation), DL4YHF <=