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#!/usr/bin/env python
# -*- coding: utf-8 -*-
#
# This is the main program that
# - runs rtl_sdr to record files containing samples
# - runs correlate_with_ref to calculate the CIR
# - runs a webserver to present the information
#
# Copyright (C) 2016
# Matthias P. Braendli, matthias.braendli@mpb.li
# http://www.opendigitalradio.org
# Licence: The MIT License, see LICENCE file
import sys
from bottle import route, run, template, static_file, request
import subprocess
import time
import multiprocessing as mp
import correlate_with_ref
import shlex
import argparse
# The record and correlate tasks run in alternance.
# Maybe later we want to run them simultaneously in a small
# pipeline.
class RTLSDR_CIR_Runner(mp.Process):
def __init__(self, options, iq_file, fig_file):
"""Initialise a new runner, which runs rtl_sdr
that will save to iq_file, and run the CIR analysis
that will save to fig_file.
options must contain freq, rate and samps fields"""
mp.Process.__init__(self)
self.events = mp.Queue()
self.freq = options.freq
self.rate = options.rate
self.samps = options.samps
self.iq_file = iq_file
self.fig_file = fig_file
def stop(self):
self.events.put("quit")
def run(self):
while True:
time.sleep(1)
try:
self.do_one_cir_run()
except Exception as e:
print("Exception occurred: {}".format(e))
try:
ev = self.events.get_nowait()
if ev == "quit":
break
except mp.queues.Empty:
pass
def do_one_cir_run(self):
# Build the rtl_sdr command line from the settings in config
rtl_sdr_cmdline = shlex.split("rtl_sdr -f {} -s {} -g 20 -S -".format(self.freq, self.rate))
dd_cmdline = shlex.split("dd of={} bs=2 count={}".format(self.iq_file, self.samps))
# To avoid calling the shell, we do the pipe between rtlsdr and dd using Popen
rtlsdr_proc = subprocess.Popen(rtl_sdr_cmdline, stdout=subprocess.PIPE)
dd_proc = subprocess.Popen(dd_cmdline, stdin=rtlsdr_proc.stdout)
# close our connection to the pipe so that rtlsdr gets the SIGPIPE
rtlsdr_proc.stdout.close()
dd_proc.communicate()
dd_proc.wait()
rtlsdr_proc.wait()
# The RTLSDR outputs u8 format
print("Starting correlation")
cir_corr = correlate_with_ref.CIR_Correlate(self.iq_file, "u8")
cir_corr.plot(self.fig_file)
@route('/')
def index():
return template('index',
rtl_sdr_cmdline = "rtl_sdr",
fig_file = FIG_FILE)
@route('/static/<filename:path>')
def send_static(filename):
return static_file(filename, root='./static')
if __name__ == '__main__':
parser = argparse.ArgumentParser(description='DAB Channel Impulse Measurement for RTL-SDR')
# Options for the webserver
parser.add_argument('--host', default='127.0.0.1', help='socket host (default: 127.0.0.1)',required=False)
parser.add_argument('--port', default='8000', help='socket port (default: 8000)',required=False)
# Options for RTLSDR reception
parser.add_argument('--freq', help='Receive frequency', required=True)
parser.add_argument('--samps',
default=10*196608,
help='Number of samples to analyse in one run, one transmission frame at 2048000 samples per second is 196608 samples',
required=False)
parser.add_argument('--rate', default='2048000', help='Samplerate for RTLSDR receiver (2048000)', required=False)
cli_args = parser.parse_args()
# File to save the recorded IQ file to
IQ_FILE = "static/rtlsdr.iq"
# The figures are saved to a file
FIG_FILE = "static/rtlsdr.svg"
rtlsdr_cir = RTLSDR_CIR_Runner(cli_args, IQ_FILE, FIG_FILE)
rtlsdr_cir.start()
try:
run(host=cli_args.host, port=int(cli_args.port), debug=True, reloader=False)
finally:
rtlsdr_cir.stop()
rtlsdr_cir.join()
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