i am trying to do some signal manipulation but i keep getting errors

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justin stephens 2019-3-9

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https://ww2.mathworks.cn/matlabcentral/answers/449193-i-am-trying-to-do-some-signal-manipulation-but-i-keep-getting-errors

评论： Arrian Farahani 2020-10-29

I am having some issues with the project and I was hoping that you could help. I keep getting an error when I try to run this code. the code creates two different fecieved signals and the book says that the pam command creates a random sequence of symbols drawn from the alphabet +- 1, +-3 and then uses hamming to create a pulse shape.

N=10000;                              % # symbols, oversampling factor
M=20;                                 % # symbols, oversampling factor
Ts=.0001;                             % # symbols, oversampling factor
time=Ts*N*M;                          % sampling interval & time vector
t=Ts:Ts:time;                         % sampling interval & time vector
m=pam(N,4,5);                         % 4-level signal of length N
mup=zeros(1,N*M);                     
mup(1:M:N*M)=m;                       % oversample by integer length M
ps=hamming(M);                        % blip pulse of width M
s=filter(ps,1,mup);                   % convolve pulse shape with data
fc=1000;                              % carrier freq
phoff=-1.0;                           % carrier phase
c=cos(2*pi*fc*t+phoff);               % construct carrier
rsc=s.*c;                             % modulated signal (small Carrier)
rlc=(s+1).*c;                         % modulated signal (large carrier

I keep getting an error that pam(N,4,5) does not exist but this code is strait from the book. Could anyone offer any help?

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Answer 1

Walter Roberson 2019-3-9

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https://ww2.mathworks.cn/matlabcentral/answers/449193-i-am-trying-to-do-some-signal-manipulation-but-i-keep-getting-errors#answer_364632

pam() is from the BioInformatics Toolbox, and cannot be invoked with three integer parameters.

https://www.mathworks.com/help/bioinfo/ref/pam.html

For signal processing Pulse Amplitude Modulation, the Mathworks routine is pammod . The third parameter to that is the initial phase, and it seems unlikely that you would be using an initial phase of 5 radians.

I would suggest that it is likely that "the book" supplied its own pam() routine.

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justin stephens 2019-3-10

i am very sorry that the photo is in this orientation....... i have scoured the software reciever design book for a proprietary function of pam(). That is why i am so confused about this because pam() is part of a bio library.

Arrian Farahani 2020-10-29