Down-sampling in MATLAB
The two basic operations in a multi-rate system are decreasing/down-sampling (decimation) and increasing (interpolation) the sampling rate of a signal.
In down-sampling we start with a constant time signal x(t) and convert it into a succession of tests x[n], in decimation we start with a discrete-time signal x[n] and convert it into another discrete-time signal y[n], which comprises of sub-tests of x[n].
We will be using the decimate() and stem() function.
The decimate() function is used to decrease a sample rate by an integer factor.
Syntax: a = decimate(x, r)
- x: input signal,
- r: decimation factor
Return Value: Decimated Signal
The stem() function is used to plot a discrete sequence data.
- y: data sequence
Return Value: Plot of data sequence in discrete time
MATLAB code for down-sampling: