Undefined function 'fftxx' for input arguments of type 'double'.

Undefined function 'fftxx' for input arguments of type 'double'.

Error in komtar1 (line 636) [fyy,nfyy,dfrq,velof,dispf]=fftxx(RR1,dt,np);

may i know wat is it mean and how to solve it? Thanks.

Answer 1

[John BG]

in R2015a there is no fftxx command, just fft

try fft instead of fftx

If you find this answer of any help solving this question, please click on the thumbs-up vote link, thanks in advance

John

[e-mail]

[Andrew Wawa]

currently i am using 2014a, if i am using fft instead of fftxx, the error occured as

Error using fft Too many output arguments.

Error in komtar1 (line 636) [fyy,nfyy,dfrq,velof,dispf]=fft(yy,dt,np);|__

[John BG]

Wawa

May be you would like to have a look at the DTFT

x=signal_of_interest
n=[1:1:length(L1)]   % generate time reference for x
x=double(x)
k=0:500;w=(pi/500)*k  % generate frequency reference
X=x*(exp(-j*pi/500)).^(n'*k)
X=x*(exp(-j*pi/500)).^(n'*k)
magX=abs(X);angX=angle(X);realX=real(X);imagX=imag(X)
figure(15);subplot(2,2,1);plot(k/500,magX);grid
xlabel('freq[rad]');title('Magnitude(X)')
figure(15);subplot(2,2,3);plot(k/500,angX/pi);grid
xlabel('freq[rad]');title('Phase(X)')
figure(15);subplot(2,2,2);plot(k/500,realX);grid
xlabel('freq[rad]');title('Real(X)')
figure(15);subplot(2,2,4);plot(k/500,imagX);grid
xlabel('freq[pi]');title('Imag(X)')

From

http://www.amazon.co.uk/Digital-Signal-Processing-Proakis-Paperback/dp/B011DBF7PM/ref=sr_1_9?ie=UTF8&qid=1456657741&sr=8-9&keywords=digital+signal+processing+with+MATLAB+Ingle+Proakis

send me your email and I will send you back the pages you may like to read.

Also very important, the class DSP

1.- generate a simple tone:

hsin1 = dsp.SineWave(2, 10) hsin1.SamplesPerFrame = 1000 y = step(hsin1) plot(y)

swei tone

 hsin2 = dsp.SineWave
 hsin2.Frequency = 10
 hsin2.PhaseOffset = [0 pi/2]
 y = step(hsin2)
 plot(y)

any signal shape

   hsr1 = dsp.SignalSource;
   hsr1.Signal = randn(1024, 1);
   y1 = zeros(1024,1);
   idx = 1;
   while(~isDone(hsr1))
     y1(idx) = step(hsr1);  
     idx = idx+1;
   end

2.- Use Time Scopes

hsin = dsp.SineWave('Frequency',100, 'SampleRate', 1000)
hsin.SamplesPerFrame = 10
hts1 = dsp.TimeScope('SampleRate', hsin.SampleRate,'TimeSpan', 0.1)
for ii = 1:10
     x = step(hsin)
     step(hts1, x)
end
release(hts1)

another Time Scope

Fs = 1000;  % Sampling frequency
hsin1 = dsp.SineWave('Frequency',50,...
   'SampleRate',Fs, ...
   'SamplesPerFrame', 100);
% Create FIRDecimator System object to decimate by 2
hfilt = dsp.FIRDecimator;
% Create TimeScope System object with 2 input ports (channels)
hts2 = dsp.TimeScope(2, [Fs Fs/2], ...
   'TimeDisplayOffset', [0 38/Fs], ...
   'TimeSpan', 0.25, ...
   'YLimits',[-1 1], ...
   'ShowLegend', true);
for ii = 1:2
     xsine = step(hsin1);
     xdec = step(hfilt,xsine);
     step(hts2, xsine, xdec);
end

phasors time display

fs = 1000; t = (0:1/fs:10)'
CxSine = cos(2*pi*0.2*t) + 1i*sin(2*pi*0.2*t)
CxSineSum = cumsum(CxSine)
figure(101); subplot(2,1,1); stairs(t,abs(CxSineSum))  % Plot magnitude
subplot(2,1,2); stairs(t,(180/pi)*angle(CxSineSum))   % Plot phase in deg
h1 = dsp.TimeScope(1, fs, 'TimeSpanSource', 'Auto')
step(h1,CxSineSum)
set(h1,'PlotAsMagnitudePhase',true)
release(h1)
% close(101)
% clear h1 fs t CxSine CxSineSum

3.- Spectrum Analyzer, 2 tones

hsin = dsp.SineWave('Frequency',100,'SampleRate',1000) hsin.SamplesPerFrame = 1000 hsa = dsp.SpectrumAnalyzer('SampleRate',hsin.SampleRate) for ii = 1:250 x = step(hsin) + 0.05*randn(1000,1) step(hsa, x) end release(hsa) % clear('hsa')

five tones

Fs = 100e6;  % Sampling frequency
fSz = 5000;  % Frame size

hsin1 = dsp.SineWave(1e0,   5e6, 0, 'SamplesPerFrame', fSz, 'SampleRate', Fs)
hsin2 = dsp.SineWave(1e-1, 15e6, 0, 'SamplesPerFrame', fSz, 'SampleRate', Fs)
hsin3 = dsp.SineWave(1e-2, 25e6, 0, 'SamplesPerFrame', fSz, 'SampleRate', Fs)
hsin4 = dsp.SineWave(1e-3, 35e6, 0, 'SamplesPerFrame', fSz, 'SampleRate', Fs)
hsin5 = dsp.SineWave(1e-4, 45e6, 0, 'SamplesPerFrame', fSz, 'SampleRate', Fs)

hsb = dsp.SpectrumAnalyzer
hsb.SampleRate = Fs
hsb.SpectralAverages = 1
hsb.PlotAsTwoSidedSpectrum = false
hsb.RBWSource = 'Auto'
hsb.PowerUnits = 'dBW'
hsb.Position = [749 227 976 721]
for idx = 1:1e2 
     y1 = step(hsin1)
     y2 = step(hsin2)  
     y3 = step(hsin3)
     y4 = step(hsin4)
     y5 = step(hsin5)
     step(hsb,y1+y2+y3+y4+y5+0.0001*randn(fSz,1))
end
release(hsb)
release('hsb')

chirp

Fs = 233e3
frameSize = 20e3
hchirp = dsp.Chirp('SampleRate',Fs,...
  'SamplesPerFrame',frameSize,...
  'InitialFrequency',11e3,...
  'TargetFrequency',11e3+55e3)

hss = dsp.SpectrumAnalyzer('SampleRate',Fs)
hss.SpectrumType = 'Spectrogram'
hss.RBWSource = 'Property'
hss.RBW = 500
hss.TimeSpanSource = 'Property'
hss.TimeSpan = 2
hss.PlotAsTwoSidedSpectrum = false

for idx = 1:50
  y = step(hchirp)+ 0.05*randn(frameSize,1)
  step(hss,y)
end
release(hss)

hope it helps

John