add a millisecond of silence to a sound?

i do create a white noise sound and i want to add a milliseconds of silence moment to it. how to do that? and how to customize the location of the silence and the duration? this is the code:

    % clc;clear all;close all;
sf = 44100;  
d= input('total duration of stimulus (in sec) = ');
n = sf * d;  
noise = randn(1, n);          
noise = noise / max(abs(noise)); 
disp('WhiteNoise');
sound(noise, sf); 
x = linspace(0, d, n);
plot(x,noise); 
xlabel('time (s)'); 
title('sound: noise');
grid on;

thank you.

Answer 1

[Image Analyst]

Use zeros() to insert zero, something like

signal = [signal(1:index), ones(1, numSamples), signal(index+1:end)]

Vary index and numSamples, and variable names to achieve what you want.