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Hello!
As a follow-up to the SDR Pluto Roadtest forum thread I have a question to the MATLAB experts: considering home licensing model, what add-ons are required/nice to have for - for example - SDR related, entry level experiments?
It seems that at least:
are needed in addition to the main license...
A fun simple MATLAB script that I think uses just the Communications Toolbox:
% FM I/Q WAV file generator
% rev 1 - shabaz - feb 2024
% Generates a WAV file containing I and Q components of an
% FM modulated signal. The audio source is a mono WAV file.
% Sample rates are 48 kHz for input and output.
% input audio
audio_fname = 'eveshort-48-mono.wav';
% FM modulation parameters, fd = frequency deviation
fd = 5e3; % 5 kHz
out_bw = 2*(fd + 12e3); % 2*(freq deviation + audio bandwidth (12kHz))
out_fs = 2*out_bw; % 180*2 = 44ksps
% might as well make it 48ksps, for a round number!
out_fs = 48e3;
% read in the source audio
[x,fs] = audioread(audio_fname);
% create the FM modulator object
fmmodulator = comm.FMModulator( ...
'SampleRate',out_fs, ...
'FrequencyDeviation',fd);
% perform the FM modulation
y = fmmodulator(x);
% obtain the I/Q components
I = real(y);
Q = imag(y);
% build the stereo WAV file containing the I and Q outputs
IQ_stereo = [I';Q']';
audiowrite('iq_file.wav', IQ_stereo, 48e3);
Hopefully the comments make sense. It converts an input mono WAV audio file, into an output WAV stereo file that has FM modulated I/Q output at baseband.
You could play the stereo output file using any media player, and you should hear distortion.
You can then play that file using any free SDR software on your PC, to demodulate the FM and convert back to the original audio.
I've placed the file plus the example WAV input and the generated output file (so that anyone can try it without requiring MATLAB) here: https://github.com/shabaz123/fm_iq_create
This is the example mono input file content:
And this is the output WAV file with FM modulation, with I and Q in the stereo channels:
See that GitHub link readme, to see how to use it with free SDR++ software as an example.
A fun simple MATLAB script that I think uses just the Communications Toolbox:
% FM I/Q WAV file generator
% rev 1 - shabaz - feb 2024
% Generates a WAV file containing I and Q components of an
% FM modulated signal. The audio source is a mono WAV file.
% Sample rates are 48 kHz for input and output.
% input audio
audio_fname = 'eveshort-48-mono.wav';
% FM modulation parameters, fd = frequency deviation
fd = 5e3; % 5 kHz
out_bw = 2*(fd + 12e3); % 2*(freq deviation + audio bandwidth (12kHz))
out_fs = 2*out_bw; % 180*2 = 44ksps
% might as well make it 48ksps, for a round number!
out_fs = 48e3;
% read in the source audio
[x,fs] = audioread(audio_fname);
% create the FM modulator object
fmmodulator = comm.FMModulator( ...
'SampleRate',out_fs, ...
'FrequencyDeviation',fd);
% perform the FM modulation
y = fmmodulator(x);
% obtain the I/Q components
I = real(y);
Q = imag(y);
% build the stereo WAV file containing the I and Q outputs
IQ_stereo = [I';Q']';
audiowrite('iq_file.wav', IQ_stereo, 48e3);
Hopefully the comments make sense. It converts an input mono WAV audio file, into an output WAV stereo file that has FM modulated I/Q output at baseband.
You could play the stereo output file using any media player, and you should hear distortion.
You can then play that file using any free SDR software on your PC, to demodulate the FM and convert back to the original audio.
I've placed the file plus the example WAV input and the generated output file (so that anyone can try it without requiring MATLAB) here: https://github.com/shabaz123/fm_iq_create
This is the example mono input file content:
And this is the output WAV file with FM modulation, with I and Q in the stereo channels:
See that GitHub link readme, to see how to use it with free SDR++ software as an example.