Add file with dab constants

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