[Discuss-gnuradio] Still confused about the IF frequency

[Sachi]

Hi, Eric and Matt

I still can't understand the question I asked in July
26th's email.  Hope you could take a look at the email
titled "confusion about set_rx_freq()".

My understanding is, if we get a "reversed version" of
the spectrum, we eventually get the "conjugate
version" of the signal in time domain, that is, I
channel remains the same, Q channel is reversed.  So
in "gr_quadrature_demod_cf", when we use "arg(in[i] *
conj (in[i-1]))" to approximate the frequency, we
shouldn't get the same thing.  Do I make any mistakes
here?

However, in Matt's email on Feb, 16th, Matt said, 
"
1 - 0.765625 = .234375

.234375 * 64 MHz = 15 MHz

Since we had to do that "reflection", the spectrum is
reversed.  This isn't a
problem for FM, but needs to be taken into account for
most modulations.

Matt
"

I wonder why it's not a problem for FM??

Thank you very much, looking forward to your reply

Sachi


                
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