Down-sampling a signal after convolution

1. How do you downsample a signal?
2. Which signals can be down sampled?
3. Why do we downsample a signal?
4. Does downsampling cause aliasing?

How do you downsample a signal?

y = downsample( x , n ) decreases the sample rate of x by keeping the first sample and then every n th sample after the first. If x is a matrix, the function treats each column as a separate sequence. y = downsample( x , n , phase ) specifies the number of samples by which to offset the downsampled sequence.

Which signals can be down sampled?

5 Which signals can be downsampled? A signal can be downsampled (without doing any filtering) whenever it is “oversampled”, that is, when a sampling rate was used that was greater than the Nyquist criteria required. Specifically, the signal's highest frequency must be less than half the post-decimation sampling rate.

Why do we downsample a signal?

(1) To make a digital audio signal smaller by lowering its sampling rate or sample size (bits per sample). Downsampling is done to decrease the bit rate when transmitting over a limited bandwidth or to convert to a more limited audio format.

Does downsampling cause aliasing?

If a discrete-time signal's baseband spectral support is not limited to an interval of width 2 π / M radians, downsampling by M results in aliasing. Aliasing is the distortion that occurs when overlapping copies of the signal's spectrum are added together.