Hi all, There's a bug in the block for the DBPSK modulator. The "differential" param isn't set to True in dbpsk_mod; it's just left to default, and differential defaults to False in the bpsk_mod block. So it really acts like a BPSK modulator. QPSK was the same. Here's a patch.
diff --git a/gr-digital/python/digital/bpsk.py b/gr-digital/python/digital/bpsk.py index 57cf253..92f3254 100644 --- a/gr-digital/python/digital/bpsk.py +++ b/gr-digital/python/digital/bpsk.py @@ -117,7 +117,7 @@ class dbpsk_mod(bpsk_mod): def __init__(self, mod_code=None, *args, **kwargs): - super(dbpsk_mod, self).__init__(*args, **kwargs) + super(dbpsk_mod, self).__init__(differential=True, *args, **kwargs) # ///////////////////////////////////////////////////////////////////////////// # DBPSK demodulator @@ -139,7 +139,7 @@ class dbpsk_demod(bpsk_demod): def __init__(self, mod_code=None, *args, **kwargs): - super(dbpsk_demod, self).__init__(*args, **kwargs) + super(dbpsk_demod, self).__init__(differential=True, *args, **kwargs) # # Add these to the mod/demod registry diff --git a/gr-digital/python/digital/qpsk.py b/gr-digital/python/digital/qpsk.py index 859d981..1ed3357 100644 --- a/gr-digital/python/digital/qpsk.py +++ b/gr-digital/python/digital/qpsk.py @@ -149,7 +149,7 @@ class dqpsk_mod(qpsk_mod): __doc__ += shared_mod_args def __init__(self, mod_code=_def_mod_code, *args, **kwargs): - super(dqpsk_mod, self).__init__(mod_code, + super(dqpsk_mod, self).__init__(mod_code, True, *args, **kwargs) # ///////////////////////////////////////////////////////////////////////////// @@ -171,7 +171,7 @@ class dqpsk_demod(qpsk_demod): __doc__ += shared_demod_args def __init__(self, mod_code=_def_mod_code, *args, **kwargs): - super(dqpsk_demod, self).__init__(mod_code, + super(dqpsk_demod, self).__init__(mod_code, True, *args, **kwargs) # Incidentally, I question the need for the DBPSK mod GRC block now that we have the generic PSK mod GRC block. Might make sense to deprecate it. --n
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