Basic Question about the function ztrans

Hi,

I have a vector which represents a signal sampled at 250Hz.

I would like to perform a z transformation on this vector, although I haven't had success thus far.

This is what I have tried:

%%Band Pass Filtering
ECG = load('Testm.mat');
d = designfilt('bandpassiir','FilterOrder',10, ...
    'PassbandFrequency1',0.5,'PassbandFrequency2',50, ...
    'PassbandRipple',3, ...
    'StopbandAttenuation1',40,'StopbandAttenuation2',40, ...
    'SampleRate',250);
FD = filter(d,ECG.val(1,:)); 
fvtool(d,'Fs', 250)
%%Zero Padding
B = padarray(FD, [0 4])
%%Unilateral Z transformation
syms k x
f = B(k)
ztrans(f,k,x)

Any suggestions would be helpful

thanks

Nic

Answer 1

[Walter Roberson]

syms k x
f = B(k)

However, indexing an array by a symbolic variable is not permitted.

ztrans is to be applied to a function, not to a vector of values.

Perhaps the code shown at https://www.youtube.com/watch?v=rLcKKMcfx9o is of interest.

[Nicholas]

Thanks very much Walter - I'll review the video.

Dr. Nic