Re: the principle of "constellation modulator"?

[Fabian Schwartau]

I haven't looked into the code, but the output is a baseband signal and
its supposed to be. The word baseband implies that you do not shift to a
carrier frequency, so there is no exp(-jwt) term. I guess w is your
angular carrier frequency, which does not exists (its baseband).

Am 07.05.21 um 11:33 schrieb ????????:
> Recently I was learning the working principle of "constellation
> modulator". I read the file "generic_mod_demod.py" and realized that it
> is a hierarchical block. I was confused about its working principle, why
> there is no other action after it is connected to rrc_filter. What?
> Shouldn't the general IQ modulation have "acoswt-bsinwt" or "(a + bi)
> exp(-jwt)" operation? I haven't seen similar operations in the code, but
> the output of the "constellation modulator" is a baseband complex
> modulated signal. Is there anything else I can't see?
> mod code:
> ?0?2 ?0?2 ?0?2 ?0?2 # Connect
> ?0?2 ?0?2 ?0?2 ?0?2 self._blocks = [self, self.bytes2chunks]
> ?0?2 ?0?2 ?0?2 ?0?2 if self.pre_diff_code:
> ?0?2 ?0?2 ?0?2 ?0?2 ?0?2 ?0?2 self._blocks.append(self.symbol_mapper)
> ?0?2 ?0?2 ?0?2 ?0?2 if differential:
> ?0?2 ?0?2 ?0?2 ?0?2 ?0?2 ?0?2 self._blocks.append(self.diffenc)
> ?0?2 ?0?2 ?0?2 ?0?2 self._blocks += [self.chunks2symbols, self.rrc_filter, 
> self]
> ?0?2 ?0?2 ?0?2 ?0?2 self.connect(*self._blocks)
>