this is the code that i want to run, but got problem Undefined function or variable 'QFix'

close all; clc;

% Example Parameters

B = 6; %# of fractional bits

N = 100000; % # of samples

xn = (2*rand(1,N)-1); % Input sequence - Uniform Distribution

a = 0.9; % Filter parameter

Xm = 1-abs(a); % Scaling factor

% Local variables

bM = 7; DbM = 2^bM; % bin parameter

BB = 2^B; % useful factor in quantization

M = round(DbM/2); % Half number of bins

bins = [-M+0.5:1:M-0.5]; % Bin values from -M to M

Q = bins/DbM; % Normalized bins

YTN = 2^(-bM); % Ytick marks interval

YLM = 4*YTN; % Yaxis limit

% Quantize the input and the filter coefficients

xn = QFix(Xm*xn,B,'round','satur'); % Scaled Input quant to B bits

a = QFix(a,B,'round','satur'); % a quantized to B bits

% Filter output without multiplication quantization

yn = filter(1,[1,-a],xn); % output using filter routine

% Filter output with multiplication quantization

yq = zeros(1,N); % Initialize quantized output array

yq(1) = xn(1); % Calculation of the first sample yq(1)

for I = 2:N;

A1Y = QFix(a*yq(I-1),B,'round','satur'); % Quantization of a*y(n-1)

yq(I) = QFix(A1Y+xn(I),B,'round','satur'); % I-th sample yq(I)

end

% Output Error Analysis

en = yn-yq; % Output error sequence

varyn = var(yn); varen = var(en); % Signal and noise power

eemax = max(en); eemin = min(en); % Maximum and minimum of the error

enmax = max(abs([eemax,eemin])); % Absolute maximum range of the error

enavg = mean(en); enstd = std(en); % Mean and std dev of the error

en = round(en*(2^bM)/(2*enmax)+0.5); % Normalized en (integer between -M & M)

en = sort([en,-M:1:(M+1)]); %

H = diff(find(diff(en)))-1; % Error histogram

H = H/N; % Normalized histogram

Hmax = max(H); Hmin = min(H); % Max and Min of the normalized histogram

% Output SNRs

SNR_C = 10*log10(varyn/varen); % Computed SNR

SNR_T = 6.02 + 6.02*B + 20*log10(Xm); % Theoretical SNR

Answer 1

[Jon]

You need to make sure that the directory where the file QFix.m is located is put onto the MATLAB path.

Click the Set Path icon on the HOME tab >ENVIRONMENT on the MATLAB toolbar to add the appropriate directory(s) containing your source code.