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| -rw-r--r-- | dpd/src/const.py | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/dpd/src/const.py b/dpd/src/const.py new file mode 100644 index 0000000..1011c6c --- /dev/null +++ b/dpd/src/const.py @@ -0,0 +1,38 @@ +# DAB Frame constants +# Sources: +# - etsi_EN_300_401_v010401p p145 +# - Measured with USRP B200 + +import numpy as np + +class const: + def __init__(self, sample_rate): + self.sample_rate = sample_rate + + # Time domain + self.T_F = sample_rate / 2048000 * 196608 # Transmission frame duration + self.T_NULL = sample_rate / 2048000 * 2656 # Null symbol duration + self.T_S = sample_rate / 2048000 * 2552 # Duration of OFDM symbols of indices l = 1, 2, 3,... L; + self.T_U = sample_rate / 2048000 * 2048 # Inverse of carrier spacing + self.T_C = sample_rate / 2048000 * 504 # Duration of cyclic prefix + + # Frequency Domain + # example: np.delete(fft[3328:4865], 768) + self.FFT_delete = 768 + self.FFT_delta = 1536 # Number of carrier frequencies + if sample_rate == 2048000: + self.FFT_start = 256 + self.FFT_end = 1793 + elif sample_rate == 8192000: + self.FFT_start = 3328 + self.FFT_end = 4865 + else: + raise RuntimeError("Sample Rate '{}' not supported".format( + sample_rate + )) + + # Calculate sample offset from phase rotation + # time per sample = 1 / sample_rate + # frequency per bin = 1kHz + # phase difference per sample offset = delta_t * 2 * pi * delta_freq + self.phase_offset_per_sample = 1. / sample_rate * 2 * np.pi * 1000 |