Fm blocks

I am trying to do sdr radar. I will send linear fm modulated signal and
then take it. I am seaching fm modulating blocks in grc. I ran some
examples but could not understand it is true or not. I also looked nbfm
and wbfm transmitter and receiver blocks in grc but i could not find any
documents about these blocks. For example what do audio_rate and
quadrature_rate mean? I must do linear fm transmitter and receiver for
our project. Could you help me if you have any documents or opion?

2011/2/24 Ingmar M. [email protected]:

If I remember correctly the audio rate is literally the data rate your sound
card is sampling at eg 32kHz or 44.1kHz and quad rate is the incoming rf
sampling rate. For example you may have sampled your RF at 128kHz and be
running your audio (or whatever) at 32kHz.

Yes, that’s it. If, for a simple example, you have:

sig_source_f → nbfm_tx → usrp_sink_c

The audio rate would be the rate from the signal source and the
quadrature rate would be the output rate of the nbfm_tx that you send
to the URSP sink (usrp ADC rate / interp).