frequency-guard.py

#!/usr/bin/python3
#
# Sample of measuring and frequency correction with ACOUNTER02A

import time
import datetime
import sys
from pymlab import config
import os
from mlabutils import ejson
import numpy as np


#import logging
#logging.basicConfig(level=logging.DEBUG)

parser = ejson.Parser()

if len(sys.argv) != 3:
    sys.stderr.write("Invalid number of arguments. Missing path to a config files!\n")
    sys.stderr.write("Usage: %s config_file.json i2c_bus.cfg\n" % (sys.argv[0], ))
    sys.exit(1)

value = parser.parse_file(sys.argv[1])

# path to metadata output directory
path = value['configurations'][0]['children'][0]['metadata_path']

# required frequency
carrier_freq = value['configurations'][0]['children'][0]['transmitter_carrier'] # Beacon frequency
low_detect_freq = value['configurations'][0]['children'][0]['children'][1]['low_detect_freq']
hi_detect_freq = value['configurations'][0]['children'][0]['children'][1]['hi_detect_freq']

echo_freq = (hi_detect_freq + low_detect_freq)/2        # hearing frequency
req_freq = (carrier_freq - echo_freq) * 2

# station name
StationName = value['configurations'][0]['children'][0]['origin']

print("RMDS Station Local Oscillator Tunning Utility")

#### Sensor Configuration ###########################################

while True:


    cfg = config.Config()
    cfg.load_file(sys.argv[2])

    try:
        cfg.initialize()

        fcount = cfg.get_device("counter")
        fgen = cfg.get_device("clkgen")
        time.sleep(0.5)
        fcount.route()
        current_freq = fcount.get_freq()
        fcount.route()
        fcount.set_GPS()        # set GPS configuration
        frequencies = np.array([current_freq])


        #### Data measurement and logging ###################################################


        sys.stdout.write("\r\nCarrier Freq.: %3.6f MHz, Echo Freq.: %3.3f kHz, Req. Freq.: %3.6f MHz\r\n\n" % (carrier_freq/1e6, echo_freq/1e3, req_freq/1e6))

        while True:
            now = datetime.datetime.now()
            filename = path + time.strftime("%Y%m%d%H", time.gmtime())+"0000_"+StationName+"_freq.csv"
            # print("Log filename", filename)
            if not os.path.exists(filename):
                with open(filename, "a") as f:
                    f.write('#timestamp,LO_Frequency,Hit,StdDev \n')

            if (now.second == 15) or (now.second == 35) or (now.second == 55):
                fcount.route()
                current_freq = fcount.get_freq()
                freq_error = current_freq - req_freq

                if (abs(freq_error) > 1e6):
                    """ If frequency error is unrealistically big, we reset the GPS firstly before setting the new oscillator frequency"""
                    fcount.route()
                    fcount.set_GPS()    # set GPS configuration
                    time.sleep(30)      # wait for relevant frequency measurement.

                    while not ((now.second == 15) or (now.second == 35) or (now.second == 55)): # waiting for correct time for frequency readout.
                        pass

                    current_freq = fcount.get_freq()
                    fgen.route()
                    regs = fgen.set_freq(current_freq/1e6, float(req_freq/1e6))
                    frequencies = np.empty([1])
                    frequencies[:] = np.NAN
                    freq_corr="E"

                elif (abs(freq_error) > (3*np.nanstd(frequencies))):                # set new parameters to oscilator only if the error is significant.
                    if (len(frequencies) > 3):
                        fgen.route()
                        mean_frequency = np.nanmean(frequencies)
                        regs = fgen.set_freq(mean_frequency/1e6, float(req_freq/1e6))
                        frequencies = np.array([mean_frequency])
                        freq_corr="Y"
                    else:
                        freq_corr="P"
                        frequencies = np.append(frequencies, current_freq)

                else:
                    frequencies = np.append(frequencies, current_freq)
                    if (len(frequencies) > 30):
                        frequencies = np.delete(frequencies, 0)
                    freq_corr="N"

                with open(filename, "a") as f:
                    f.write("%.1f,%.1f,%s\n" % (time.time(), current_freq, freq_corr))


            sys.stdout.write("Current Freq.: %3.7f MHz, StdDev: %4.2f Hz , Req. Freq.: %3.6f MHz, Freq Error: %3.1f Hz, Time: %d s \r" % (current_freq/1e6, frequencies.std(), req_freq/1e6, (current_freq - req_freq), now.second ))
            sys.stdout.flush()
            time.sleep(0.9)

    except IOError as e:
        sys.stdout.write("\r\n************ I2C Error\r\n")
        print(repr(e))
        time.sleep(5)

    except KeyboardInterrupt:
        sys.stdout.write("\r\n")
        sys.exit(0)