### Time Invariance Property: FIR Examples

When a time-invariant system is cascaded with a time-delay system, the order of the two systems does not matter. Thus we can delay the input $$x[n]$$ and then filter it, or we can filter $$x[n]$$ and then delay it. The following two demos show the details of these cascaded implementations for two different filters.
 1st difference filter Here is a block diagram example of time invariance with the 1st difference filter. Click on any of the blocks, the input or the output for a close-up. 5-point averager Here is a block diagram example of time invariance with the 5-point averager. Click on any of the blocks, the input or the output for a close-up.