Re: [Discuss-gnuradio] Re: Frequency dependent problem after syncronizing , Please help!

[Johnathan Corgan]

On Thu, Feb 12, 2009 at 1:20 PM, Bruhtesfa Ebrahim <address@hidden> wrote:

> What makes it strange is the dependence on gain.when the linear gain in
> the spectrum panel(usrp_fft.py)is set to 0,the signal at the center(the
> DC)is 5dB higher than the noise level.When I increase the gain, the
> difference between the DC and noise level keeps decreasing and finally
> the DC level is equal to the noise level.
> Specifically, for a linear gain >=20, the signal around DC is not
> visible(it is equal to the noise level).

Actually, what you're now describing is more like not receiving any
signal at all--the small line at DC is residual DC offset from the
ADC, and the noise is simply that, noise that gets amplified according
to the gain setting.  At a certain point the noise power exceeds the
small DC offset.

Johnathan