FFT of real signals using MATLAB

JoannesPaulus said:

You are reading the serial port incorrectly. Try:

Code:

data=zeros(1,L);
for l=1:L
  data(l)=hex2dec(fscanf(ser,'%s'));
end

Instead of your "while(1)" loop.

Click to expand...

JoannesPaulus said:

"data" is an array of decimals of L columns and 1 row. "data(l)" is 1 element of that array. If the number of elements in your file is larger than 1, you get that error message. Check the size of your data!

Click to expand...

Example — Reading Binary Data


This example illustrates how you can download the TDS 210 oscilloscope screen display to MATLAB. The screen display data is transferred and saved to disk using the Windows bitmap format. This data provides a permanent record of your work, and is an easy way to document important signal and scope parameters.

Because the amount of data transferred is expected to be fairly large, it is asynchronously returned to the input buffer as soon as it is available from the instrument. This allows you to perform other tasks as the transfer progresses. Additionally, the scope is configured to its highest baud rate of 19,200.

Create a serial port object — Create the serial port object s associated with serial port COM1.
s = serial('COM1');


Configure property values — Configure the input buffer to accept a reasonably large number of bytes, and configure the baud rate to the highest value supported by the scope.
s.InputBufferSize = 50000;
s.BaudRate = 19200;


Connect to the device — Connect s to the oscilloscope. Because the default value for the ReadAsyncMode property is continuous, data is asynchronously returned to the input buffer as soon as it is available from the instrument.
fopen(s)


Write and read data — Configure the scope to transfer the screen display as a bitmap.
fprintf(s,'HARDCOPYORT RS232')
fprintf(s,'HARDCOPY:FORMAT BMP')
fprintf(s,'HARDCOPY START')


Wait until all the data is sent to the input buffer, and then transfer the data to the MATLAB workspace as unsigned 8-bit integers.
out = fread(s,s.BytesAvailable,'uint8');


Disconnect and clean up — When you no longer need s, disconnect it from the instrument and remove it from memory and from the MATLAB workspace.
fclose(s)
delete(s)
clear s

Click to expand...

JoannesPaulus said:

If I were you, I would try to read just one 8-bit word, check how it looks and then try to read a sequence.
From the matlab documentation:

Click to expand...