Changing the size on input 1 is not allowed without first calling the release() method.

I want to generate the 16ASK modulation using apskmod function by modifying the Autometic Modulation classifcation example of MATALB, but got an error. here x is the audio wave file.

sps = 8;
modulationTypes = categorical(["BPSK", "QPSK", "8PSK", "16PSK","32PSK"...
  "16QAM", "32QAM","64QAM","128QAM", "256QAM","16APSK","PAM4", "GFSK", "CPFSK" ...
  "B-FM", "DSB-AM", "SSB-AM"]);
rng(1235)
tic

numModulationTypes = length(modulationTypes);
for modType = 1:numModulationTypes
    fprintf('%s - Generating %s frames\n', ...
      datestr(toc/86400,'HH:MM:SS'), modulationTypes(modType))
    
    label = modulationTypes(modType);
    numSymbols = (numFramesPerModType / sps);
    dataSrc = helperModClassGetSource(modulationTypes(modType), sps, 2*spf, fs);
    modulator = helperModClassGetModulator(modulationTypes(modType), sps, fs);
    if contains(char(modulationTypes(modType)), {'B-FM','DSB-AM','SSB-AM'})
      % Analog modulation types use a center frequency of 100 MHz
      channel.CenterFrequency = 100e6;
    else
      % Digital modulation types use a center frequency of 902 MHz
      channel.CenterFrequency = 902e6;
    end

The above one is main function and i have uploaded the 2 function whihc are being called by main function.

[Walter Roberson]

numFramesPerModType is not defined.

[Faheem Ur Rehman]

numFramesPerModType = 500;

[Walter Roberson]

spf is not defined. fs is not defined.

here x is the audio wave file.

? There is no reference to x in the code ?

When I put in spf = 128; fs = 22050; and run the code you posted, there is no error generated.