Frequency response of FIR (MTI delay line canceller) with non constant period

1. What is delay line canceller in MTI radar?
2. For what purpose is quartz delay line used in a moving target indicator radar?

What is delay line canceller in MTI radar?

Delay line canceller is a filter, which eliminates the DC components of echo signals received from stationary targets. This means, it allows the AC components of echo signals received from non-stationary targets, i.e., moving targets.

For what purpose is quartz delay line used in a moving target indicator radar?

Early MTI systems generally used an acoustic delay line to store a single pulse of the received signal for exactly the time between broadcasts (the pulse repetition frequency). This stored pulse will be sent to the display along with the next received pulse.