Adding reverberation channel with noisy complex sine wave

I am having a noisy multiple sine wave signal (3 sine wave with different value stated in the code) need to go thru a reverberation channel with the z transfer function of . where my a = 0.189. I wonder does my code wrote correctly? This is my first time to use the reverberation channel in transfer function for MATLAB. Please give any advise ya, thanks in advance :).

fs = 128000; %sampling frequency (samples per second) (128000)
Ts = 1/fs; %seconds per sample (time step)
f1 = 15*10^(3); % F1 sine wave frequency at 15 kHz
fa = 17*10^(3); %FA sine wave frequency at 17 kHz
f2 = 19*10^(3); %F2 sine wave frequency at 19 kHz
t1 = 0:Ts:10^(-2); %Time step

sinef1 = 0.5.*sin(2*pi*f1*t1); %generate F1 sine wave
sinefa = 0.5.*sin(2*pi*fa*t1); %generate FA sine wave
sinef2 = 0.5.*sin(2*pi*f2*t1); %generate F2 sine wave

signal = sinef1 + sinefa + sinef2; %Summing up sine wave

snr1 = 61.627; %Signal noise ratio in dB - via Calculation from variance
var = 0.088; %Variance of White Gaussian Noise
t2 = 0:Ts:10^(-2);
whitenoise = sqrt(var).*rand(1,size(signal,2)); %Generate Gaussian White noise
noisysignal = whitenoise + signal; %Adding noise to sum of signal

a = 0.189; %Calculated 'a' value as request by lecturer
syms z %Z transform
reverbz = 1 + a.*z^(-1);
reverb = iztrans(reverbz);
reverbnoisysignal = reverb + noisysignal;
figure(8)
plot(t2,reverbnoisysignal,'k');