# What is the point of decimation?

The following makes sense to me:

Decimation reduces the number of samples so it reduces the amount of data that is metered across networks and reduces the processing time for chips. That sounds great.

However, the following does not make sense to me:

I see decimation used in gnuradio-companion all the time. Often the signal is decimated to reduce the sample rate, then later the sample rate is increased somehow. What is the point of this?

Sorry for the vagueness of this question.

• Indeed "then later the sample rate is increased somehow" is quite vague. A whole data processing chain can be large. If a decimation at link 1, followed by some upsamling at link 4, is globally beneficial, then it is worth the use. Think about it: data compression (for transmission) is soomehow decimation followed by reconstruction – Laurent Duval Feb 28 '16 at 20:03