Why does decimation make a system time variant?

1. What makes a system time variant?
2. What makes a system time invariant?
3. What does decimation do to a signal?
4. Is decimator an LTI system?

What makes a system time variant?

A time-variant system is a system whose output response depends on moment of observation as well as moment of input signal application. In other words, a time delay or time advance of input not only shifts the output signal in time but also changes other parameters and behavior.

What makes a system time invariant?

A system is said to be time invariant if the response of the system to an input is not a function of time. On the other hand a system is time variant if the response to an input alters with time i.e. the system has varying response to the same input at different instants of time.

What does decimation do to a signal?

Decimation is the process of reducing the sampling frequency of a signal to a lower sampling frequency that differs from the original frequency by an integer value. Decimation also is known as down-sampling.

Is decimator an LTI system?

Decimation refers to LTI filtering followed by uniform downsampling.