How to store complex double data to WAV?

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Nik Rocky
Nik Rocky on 20 Sep 2022
Answered: Nik Rocky on 20 Sep 2022
Hello together,
I receive IQ data (real and imaginary values) from radio and save it to variable "IQ_data_before_write".
Then, I save it using (extended) audiowrite function to WAV file.
After using audioread, I get data in variable "IQ_data_after_read" back , but just real part of it.
Both data is atached.
If I visualize original and read data, I see a mirrored data at my center frequency after audiowrite + audioread.
1. how can I save whole data to WAV? (maybe split data before to real and imag, and after audioread join it again?)
2. Why is this "mirror effect" happens (see spectrum screenshot), of course of failed data? Maybe there are some another reasons (another dimensions)?
Thank you very much
Best regards
1: Original radio spectrum
2: Repeat of data spectrum stored data before writing into WAV file
3: Spectrum of reading IQ data after audiowrite and audioread)

Answers (1)

Nik Rocky
Nik Rocky on 20 Sep 2022
I found a solution by spliting to real ang imag, save it in two different wav-files.
% split data to real and imag
data_I = real(IQ_data_before_write);
data_Q = imag(IQ_data_before_write);
% write wav files
% read wav files
[out_I,Fs] = audioread('data_I.wav');
[out_Q,Fs] = audioread('data_Q.wav');
% join I and Q
data_IQ = out_I + out_Q*1i;
Read-Output has the same structure and values now




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