In audio, we use different test signals for different purposes. Up to this point, we have looked at synthesizing several test signals, all of which are periodic.
White noise is a different type of signal; it is aperiodic. It does not repeat with regular cycles.
The spectral characteristics of white noise make it a useful test signal in certain situations. If we look at white noise with a spectrum analyzer, it generally looks flat across the entire spectrum. White noise is a random signal with a likelihood of equal amplitude at all frequencies.
When it comes to synthesizing white noise in Matlab, we can use a random number generator. The syntax for using this built-in function is: y = randn(numOfSamples,1). This will create a mono noise signal with a desired number of samples.
Now that we have come up with several types of test signals, let’s start looking at how we can process these signals using different systems. First, an important process to consider is changing the amplitude of a signal.