diff options
Diffstat (limited to 'gr-digital/python/psk.py')
| -rw-r--r-- | gr-digital/python/psk.py | 76 |
1 files changed, 46 insertions, 30 deletions
diff --git a/gr-digital/python/psk.py b/gr-digital/python/psk.py index 58f6787f0c..1816ffb4ba 100644 --- a/gr-digital/python/psk.py +++ b/gr-digital/python/psk.py @@ -30,22 +30,29 @@ import digital_swig import modulation_utils from utils import mod_codes, gray_code from generic_mod_demod import generic_mod, generic_demod +from generic_mod_demod import shared_mod_args, shared_demod_args # Default number of points in constellation. _def_constellation_points = 4 # The default encoding (e.g. gray-code, set-partition) _def_mod_code = mod_codes.GRAY_CODE +# Default use of differential encoding +_def_differential = True -def create_encodings(mod_code, arity): +def create_encodings(mod_code, arity, differential): post_diff_code = None if mod_code not in mod_codes.codes: raise ValueError('That modulation code does not exist.') if mod_code == mod_codes.GRAY_CODE: - pre_diff_code = gray_code.gray_code(arity) - elif mod_code == mod_codes.SET_PARTITION_CODE: - pre_diff_code = set_partition_code.set_partition_code(arity) + if differential: + pre_diff_code = gray_code.gray_code(arity) + post_diff_code = None + else: + pre_diff_code = [] + post_diff_code = gray_code.gray_code(arity) elif mod_code == mod_codes.NO_CODE: pre_diff_code = [] + post_diff_code = None else: raise ValueError('That modulation code is not implemented for this constellation.') return (pre_diff_code, post_diff_code) @@ -54,7 +61,8 @@ def create_encodings(mod_code, arity): # PSK constellation # ///////////////////////////////////////////////////////////////////////////// -def psk_constellation(m=_def_constellation_points, mod_code=_def_mod_code): +def psk_constellation(m=_def_constellation_points, mod_code=_def_mod_code, + differential=_def_differential): """ Creates a PSK constellation object. """ @@ -62,7 +70,7 @@ def psk_constellation(m=_def_constellation_points, mod_code=_def_mod_code): if (k != int(k)): raise StandardError('Number of constellation points must be a power of two.') points = [exp(2*pi*(0+1j)*i/m) for i in range(0,m)] - pre_diff_code, post_diff_code = create_encodings(mod_code, m) + pre_diff_code, post_diff_code = create_encodings(mod_code, m, differential) if post_diff_code is not None: inverse_post_diff_code = mod_codes.invert_code(post_diff_code) points = [points[x] for x in inverse_post_diff_code] @@ -74,22 +82,26 @@ def psk_constellation(m=_def_constellation_points, mod_code=_def_mod_code): # ///////////////////////////////////////////////////////////////////////////// class psk_mod(generic_mod): + """ + Hierarchical block for RRC-filtered PSK modulation. + + The input is a byte stream (unsigned char) and the + output is the complex modulated signal at baseband. + + Args: + constellation_points: Number of constellation points (must be a power of two) (integer). + mod_code: Whether to use a gray_code (digital.mod_codes.GRAY_CODE) or not (digital.mod_codes.NO_CODE). + differential: Whether to use differential encoding (boolean). + """ + # See generic_mod for additional arguments + __doc__ += shared_mod_args def __init__(self, constellation_points=_def_constellation_points, mod_code=_def_mod_code, + differential=_def_differential, *args, **kwargs): - - """ - Hierarchical block for RRC-filtered PSK modulation. - - The input is a byte stream (unsigned char) and the - output is the complex modulated signal at baseband. - - See generic_mod block for list of parameters. - """ - - constellation = psk_constellation(constellation_points, mod_code) - super(psk_mod, self).__init__(constellation, *args, **kwargs) + constellation = psk_constellation(constellation_points, mod_code, differential) + super(psk_mod, self).__init__(constellation, differential, *args, **kwargs) # ///////////////////////////////////////////////////////////////////////////// # PSK demodulator @@ -98,21 +110,25 @@ class psk_mod(generic_mod): class psk_demod(generic_demod): + """ + Hierarchical block for RRC-filtered PSK modulation. + + The input is a byte stream (unsigned char) and the + output is the complex modulated signal at baseband. + + Args: + constellation_points: Number of constellation points (must be a power of two) (integer). + mod_code: Whether to use a gray_code (digital.mod_codes.GRAY_CODE) or not (digital.mod_codes.NO_CODE). + differential: Whether to use differential encoding (boolean). + """ + # See generic_mod for additional arguments + __doc__ += shared_mod_args def __init__(self, constellation_points=_def_constellation_points, mod_code=_def_mod_code, + differential=_def_differential, *args, **kwargs): - - """ - Hierarchical block for RRC-filtered PSK modulation. - - The input is a byte stream (unsigned char) and the - output is the complex modulated signal at baseband. - - See generic_demod block for list of parameters. - """ - - constellation = psk_constellation(constellation_points, mod_code) - super(psk_demod, self).__init__(constellation, *args, **kwargs) + constellation = psk_constellation(constellation_points, mod_code, differential) + super(psk_demod, self).__init__(constellation, differential, *args, **kwargs) # # Add these to the mod/demod registry |