matlab symbolmapping- receive error message

[Aya2002]

matlab symbolmapping

Hi experts,
i received this error message

??? Error using ==> feval
Error using ==> modem.abstractMod.checkModInputSizeBit at 13
Number of elements in each channel of input X must be an integer multiple of log2(M).

when i run the following code in matlab

clc;clear all;close all;
Tu=224e-6; %useful ofdm symbol period.
T=Tu/2048; % base band elementary period.
Kmax=1705; % number of subcarriers.
FS=4096; % IFFT/FFT length.
%%
%-------------------------------------------------
M=Kmax+1;
Data=randint(M,1,2); %Binary Data of Kmax+1=1706.
Datainp=modulate(modem.pskmod('M',8,'SymbolOrder','binary','InputType','bit'),Data);
figure(1);
subplot(211);
stem(Data(1:20));
title('Input Data');
subplot(212);
stem(real(Datainp(1:20)));
title('BPSK modulated data');

can someone explain what is the problem?

Thanks in advance

 

[AndyECE]

polishing carrier matlab

I am looking at the help file for modulate, and I think you are passing it the arguments incorrectly.

modem.pskmod('M',8,'SymbolOrder','binary','InputType','bit'),

works just fine, and gives you
Type: 'PSK Modulator'
M: 8
PhaseOffset: 0
Constellation: [1x8 double]
SymbolOrder: 'Binary'
SymbolMapping: [0 1 2 3 4 5 6 7]
InputType: 'Bit'


And you are trying to pass the object directly as an input to 'modulate', which asks for input in the form:

y = modulate(x, fc, fs), where x is the data to be modulated, fc is the carrier freqiency, and fs is the sampling rate

 

[Aya2002]

Matlab problem

can you explaine more please?

 

[Aya2002]

Matlab problem

any reply please?

 

[AndyECE]

Matlab problem

Sorry, I can't figure out how to get this working.

 

[Aya2002]

Matlab problem

realy i need your help please, let us do step by step invistigation together

Added after 1 hours 2 minutes:

In fact, when i use 4 or 2 in the modulate command, i can see the correct results but more than 4 i.e. 8, 16, 32.... i receive the mentioned problem. Can you analyse ?

Datainp=modulate(modem.pskmod('M',4,'SymbolOrder','binary','InputType','bit'),Data);

Added after 21 minutes:

Hi Freinds,
Thank you too much. I solved the problem

 

[AndyECE]

Matlab problem

Glad to hear!

 

[Aya2002]

Matlab problem

many thanks AndyECE