RXplot.py

#!/usr/bin/env python
"""
Wideband FM demodulation and plotting of baseband multiplex spectrum
Michael Hirsch, Ph.D.

Especially useful for spectrum saved from RTL-SDR with GNU Radio, GQRX, etc.
"""
from pathlib import Path
from matplotlib.pyplot import show
from radioutils import loadbin, fm_demod, playaudio
from argparse import ArgumentParser
import seaborn

seaborn.set_context("talk")

fsaudio = 48000  # [Hz], sampling rate of your soundcard for playback


def main():
    p = ArgumentParser()
    p.add_argument("fn", help="binary raw IQ capture SDR file to analyze")
    p.add_argument("fs", help="sampling frequency [Hz]", type=int)
    p.add_argument("-fc", help="baseband tunding freq [Hz]", type=float)
    p.add_argument(
        "-t",
        "--tlim",
        help="start stop increment [seconds] to load",
        type=float,
        nargs=2,
        default=(0.0, None),
    )
    p.add_argument("-v", "--verbose", action="store_true")

    P = p.parse_args()

    fn = Path(P.fn).expanduser()

    assert isinstance(P.fs, (float, int))
    fs = int(P.fs)
    # %%
    sig = loadbin(fn, fs, P.tlim)
    # %%
    m = fm_demod(sig, fs, fsaudio, P.fc, 75e3, P.verbose)
    playaudio(m, fsaudio)

    show()


if __name__ == "__main__":
    main()