1 files changed, 111 insertions, 0 deletions
diff --git a/fw/tools/hum_generator.py b/fw/tools/hum_generator.py
new file mode 100755
index 0000000..fbcabac
--- /dev/null
+++ b/fw/tools/hum_generator.py
@@ -0,0 +1,111 @@
+#!/usr/bin/env python
+# coding: utf-8
+
+import binascii
+import struct
+
+import numpy as np
+import pydub
+
+from dsss_demod_test_waveform_gen import load_noise_gen, modulate as dsss_modulate
+
+np.set_printoptions(linewidth=240)
+
+def generate_noisy_signal(
+        test_data=32,
+        test_nbits=5,
+        test_decimation=10,
+        test_signal_amplitude=20e-3,
+        noise_level=10e-3,
+        noise_spec='synth://grid_freq_psd_spl_108pt.json',
+        seed=0):
+
+    #test_data = np.random.RandomState(seed=0).randint(0, 2 * (2**test_nbits), test_duration)
+    #test_data = np.array([0, 1, 2, 3] * 50)
+    if isinstance(test_data, int):
+        test_data = np.array(range(test_data))
+
+
+    signal = np.repeat(dsss_modulate(test_data, test_nbits) * 2.0 - 1, test_decimation)
+
+    noise_gen, noise_params = load_noise_gen(noise_spec)
+    noise = noise_gen(seed, len(signal), **noise_params)
+    return np.absolute(noise + signal*test_signal_amplitude)
+
+def write_raw_frequencies_bin(outfile, **kwargs):
+    with open(outfile, 'wb') as f:
+        for x in generate_noisy_signal(**kwargs):
+            f.write(struct.pack('f', x))
+
+def synthesize_sine(freqs, freqs_sampling_rate=10.0, output_sampling_rate=44100):
+    duration = len(freqs) / freqs_sampling_rate # seconds
+    afreq_out = np.interp(np.linspace(0, duration, int(duration*output_sampling_rate)), np.linspace(0, duration, len(freqs)), freqs)
+    return np.sin(np.cumsum(2*np.pi * afreq_out / output_sampling_rate))
+
+def write_flac(filename, signal, sampling_rate=44100):
+    signal -= np.min(signal)
+    signal /= np.max(signal)
+    signal -= 0.5
+    signal *= 2**16 - 1
+    le_bytes = signal.astype(np.int16).tobytes()
+    seg = pydub.AudioSegment(data=le_bytes, sample_width=2, frame_rate=sampling_rate, channels=1)
+    seg.export(filename, format='flac')
+
+def write_synthetic_hum_flac(filename, output_sampling_rate=44100, freqs_sampling_rate=10.0, **kwargs):
+    signal = generate_noisy_signal(**kwargs)
+    print(signal)
+    write_flac(filename, synthesize_sine(signal, freqs_sampling_rate, output_sampling_rate),
+            sampling_rate=output_sampling_rate)
+
+def emulate_adc_signal(adc_bits=12, adc_offset=0.4, adc_amplitude=0.25, freq_sampling_rate=10.0, output_sampling_rate=1000, **kwargs):
+    signal = synthesize_sine(generate_noisy_signal(), freq_sampling_rate, output_sampling_rate)
+    signal = signal*adc_amplitude + adc_offset
+    smin, smax = np.min(signal), np.max(signal)
+    if smin < 0.0 or smax > 1.0:
+        raise UserWarning('Amplitude or offset too large: Signal out of bounds with min/max [{smin}, {smax}] of ADC range')
+    signal *= 2**adc_bits -1
+    return signal
+
+def save_adc_signal(fn, signal, dtype=np.uint16):
+    with open(fn, 'wb') as f:
+        f.write(signal.astype(dtype).tobytes())
+
+def write_emulated_adc_signal_bin(filename, **kwargs):
+    save_adc_signal(filename, emulate_adc_signal(**kwargs))
+
+def hum_cmd(args):
+    write_synthetic_hum_flac(args.out_flac,
+            output_sampling_rate=args.audio_sampling_rate,
+            freqs_sampling_rate=args.frequency_sampling_rate,
+            test_data = np.array(list(binascii.unhexlify(args.data))),
+            test_nbits = args.symbol_bits,
+            test_decimation = args.decimation,
+            test_signal_amplitude = args.signal_level/1e3,
+            noise_level = args.noise_level/1e3,
+            noise_spec=args.noise_spec,
+            seed = args.random_seed)
+
+
+if __name__ == '__main__':
+    import argparse
+    parser = argparse.ArgumentParser()
+    cmd_parser = parser.add_subparsers(required=True)
+    hum_parser = cmd_parser.add_parser('hum', help='Generated artificial modulated mains hum')
+    # output parameters
+    hum_parser.add_argument('-a', '--audio-sampling-rate', type=int, default=44100)
+
+    # modulation parameters
+    hum_parser.add_argument('-f', '--frequency-sampling-rate', type=float, default=10.0*100/128)
+    hum_parser.add_argument('-b', '--symbol-bits', type=int, default=5, help='bits per symbol (excluding sign bit)')
+    hum_parser.add_argument('-n', '--noise-level', type=float, default=1.0, help='Scale synthetic noise level')
+    hum_parser.add_argument('-s', '--signal-level', type=float, default=20.0, help='Synthetic noise level in mHz')
+    hum_parser.add_argument('-d', '--decimation', type=int, default=10, help='DSSS modulation decimation in frequency measurement cycles')
+    hum_parser.add_argument('-r', '--random-seed', type=int, default=0)
+    hum_parser.add_argument('--noise-spec', type=str, default='synth://grid_freq_psd_spl_108pt.json')
+    hum_parser.add_argument('out_flac', metavar='out.flac', help='FLAC output file')
+    hum_parser.add_argument('data', help='modulation data hex string')
+    hum_parser.set_defaults(func=hum_cmd)
+
+    args = parser.parse_args()
+    args.func(args)
+