Hello,
I’m trying to use the freq_xlating filter to select a narrowband portion
of
a wideband signal, but I’m a bit confused as to exactly how much I’m
changing the center frequency of the filter from the baseband value.
Could
someone break it down for me please: here is where i create the filter -
gr.freq_xlating_fir_filter_ccc(sw_decim, #decim
chan_coeffs1, #taps
???,
#center
freq
sw_decim * self._spb)
#sampling
freq
Suppose I wanted to select a channel (of width determined by chan_coeffs
taps) that is 500kHz offset from baseband. Since we’re working with
normalized frequency, I would enter the ratio of 500kHz to the sampling
frequency as the center freq. However, in trying to determine the value
of
sw_decim * self._spb I just put a simple print statement so that it
displays, giving me the answer “2”. What are the units of this?
Thanks very much!
Ben