SDR(Software Defined Radio)

  

 

 

 

Python

 

 

This example using the Python package pyrtlsdr which is available in the official site here. I used the package version 0.2.92 and Python version 3.8 on Windows 10.

 

NOTE 1 : To run this script, you need to get RTL-SDR driver installed and confirm working. See this page on how to install and test the driver.

 

from pylab import *

from rtlsdr import *

 

sdr = RtlSdr()

 

# configure device

sdr.sample_rate = 2.4e6

sdr.center_freq = 105.5e6

sdr.gain = 4

 

samples = sdr.read_samples(256*1024)

sdr.close()

 

# use matplotlib to estimate and plot the PSD

psd(samples, NFFT=1024, Fs=sdr.sample_rate/1e6, Fc=sdr.center_freq/1e6)

xlabel('Frequency (MHz)')

ylabel('Relative power (dB)')

 

show()

 

 

 

NOTE 2 : This python package requires some dependancies called librtlsdr. I used librtlsdr v0.8 that you can get from here. I used the package as highlighbed below.

 

 

 

 

 

C:\Users\jaeku\AppData\Local\Programs\Python\Python38\Lib\site-packages\rtlsdr

 

 

modify librtlsdr.py as follows :

import sys

import os

import ctypes    # add this line

from ctypes import *

from ctypes.util import find_library

 

def load_librtlsdr():

    if sys.platform == "linux" and 'LD_LIBRARY_PATH' in os.environ.keys():

        ld_library_paths = [local_path for local_path in os.environ['LD_LIBRARY_PATH'].split(':') if local_path.strip()]

        driver_files = [local_path + '/librtlsdr.so' for local_path in ld_library_paths]

    else:

        driver_files = []

    driver_files += ['librtlsdr.so', 'rtlsdr/librtlsdr.so']

    driver_files += ['rtlsdr.dll', 'librtlsdr.so']

    driver_files += ['..//rtlsdr.dll', '..//librtlsdr.so']

    driver_files += ['rtlsdr//rtlsdr.dll', 'rtlsdr//librtlsdr.so']

    driver_files += [lambda : find_library('rtlsdr'), lambda : find_library('librtlsdr')]

    dll = None

 

# Comment out following part

#    for driver in driver_files:

#        if callable(driver):

#            driver = driver()

#        try:

#            dll = CDLL(driver)

#            break

#        except:

#            pass

#    else:

#        raise ImportError('Error loading librtlsdr. Make sure librtlsdr '\

#                          '(and all of its dependencies) are in your path')

 

    dll = ctypes.WinDLL ("c:\\rtlsdrlib\\librtlsdr.dll")  # add this line

                          

    return dll

 

 

 

Reference :

 

[1] Using GNU Radio Companion Part 1

[2] GNU Radio Companion, Part 2

[3] eapbg #59 Intro to GNU Radio Companion, reading a key fob with SDR

[4] Writing GNU Radio Blocks