Please house, how can i successfully convert this matlab fft code to a verilog hdl for cyclone III fpga..?? it keeps giving me error that the function "fft" is not explicit even after making it extrinsic using the "coder.extrinsic" command.

function [xfft,ffc] = My_function(f1,f2,f3) Fs = 2000; %sampling frequency should be at least twice signal frequency %in accordance with Nyquist. Ts = 1/Fs; %sampling frequency. dt = 0:Ts:4-Ts; %signal duration. %f1 = 20; % frequency of first signal in Hz. %f2 = 70; % frequency of second signal in Hz. %f3 = 150; % frequency of third signal in Hz.

% Y = A sin(2*pi*ft+theta); theta assume to be zero.

y1 = 10*sin(2*pi*f1*dt); y2 = 10*sin(2*pi*f2*dt); y3 = 10*sin(2*pi*f3*dt); y4 = y1+y2+y3;

% subplot(4,1,1); % plot(dt,y1,'r'); % subplot(4,1,2); % plot(dt,y2,'r'); % subplot(4,1,3); % plot(dt,y3,'r'); % subplot(4,1,4); % plot(dt,y4,'r');

coder.extrinsic('fft','nextpow2');

N =length(y4); % length of time domain signal. N2=2^nextpow2(N); % length of time domain signal in power of 2. ff = fft(y4,N2); %ffl = ff(1:nfft2/2); % left side of the symetric function ff. xfft = Fs*(0:N2-1)/N2; %plot(abs(ff)); %plot(abs(ffl)); %plot(xfft,abs(ffl)); %ffl = ffl/max(ffl); % to normalize amplitude of frequency domain signal. ffc = ff(1:N2); ffc = ffc/max(ffc); %plot(abs(ffc));

% coder.extrinsic declaration coder.extrinsic('subplot','plot','xlabel','ylabel','title');

subplot(2,1,1); plot(dt,y4,'r') xlabel('Time (s)'); ylabel('Amplitude'); title('Time Domain Signal');

subplot(2,1,2); plot(xfft,abs(ffc),'r') xlabel('Frequency (Hz)'); ylabel('Normalize Amplitude'); title('Frequency Domain Signal'); end