%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% Altera NCO Compiler version 6.1% file : NCO_tb.m%% Description : The following Matlab testbench excercises the NCO model NCO_model.m% generated by Altera's NCO Compiler Megacore and outputs the sine and cosine waveforms% to the variables sin_out and cos_out respectively%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% Parameter description% N : the length of input and output arrays% fs : the desired sampling rate. For Multi-channel NCO's the channelized sample rate is fs/M %      ehre M is the number of channels%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%N=2048*1;fs = 1.0E8;% Input arrays% phi_inc_i : input phase increment : Length N (required)phi_inc_i = 42949673.*ones(1,N);% freq_mod_i : frequency modulation input : Length N (optional)freq_mod_i = zeros(1,N);% phase_mod_i : phase modulation input : Length N (optional)phase_mod_i = zeros(1,N);%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% function call to generated nco function[sin_out,cos_out] = NCO_model(phi_inc_i,phase_mod_i,freq_mod_i);fid_s = fopen('fsin_o_NCO_matlab.txt','w');fid_c = fopen('fcos_o_NCO_matlab.txt','w');for i=1:N  fprintf(fid_s,'%f\n',sin_out(i));  fprintf(fid_c,'%f\n',cos_out(i));end% Plot Channel 0 Time-Domain Outputxvalst = (0:1/fs:((N/1)-1)/fs);figure,stairs(xvalst,sin_out(1:1:N),'r');hold on, stairs(xvalst,cos_out(1:1:N),'b');legend('sine','cosine');title ('Time-Domain Plot of NCO Channel 0 Output');grid on;zoom on;xlabel ('Time');ylabel ('Amplitude');ncofftwinplot(sin_out(1:1:N),fs,0,'r');ncofftwinplot(cos_out(1:1:N),fs,1,'b');