FIR and downsampling

1. What is meant by downsampling?
2. What does FIR mean in filter?
3. What is the difference between downsampling and decimation?
4. What happens in downsampling?

What is meant by downsampling?

(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. Contrast with upsample.

What does FIR mean in filter?

The finite impulse response (FIR) filter is a nonrecursive filter in that the output from the filter is computed by using the current and previous inputs. It does not use previous values of the output, so there is no feedback in the filter structure.

What is the difference between downsampling and decimation?

Loosely speaking, “decimation” is the process of reducing the sampling rate. In practice, this usually implies lowpass-filtering a signal, then throwing away some of its samples. “Downsampling” is a more specific term which refers to just the process of throwing away samples, without the lowpass filtering operation.

What happens in downsampling?

Downsampling. The idea of downsampling is remove samples from the signal, whilst maintaining its length with respect to time. For example, a time signal of 10 seconds length, with a sample rate of 1024Hz or samples per second will have 10 x 1024 or 10240 samples.