Polyphase FIR image downscaling

1. What is polyphase fir filter?
2. How do poly phase filtering save computations in decimation filter?
3. Why polyphase filter is used?
4. What is polyphase decomposition in DSP?

What is polyphase fir filter?

Polyphase is a way of doing sampling-rate conversion that leads to very efficient implementations. But more than that, it leads to very general viewpoints that are useful in building filter banks.

How do poly phase filtering save computations in decimation filter?

The concept behind a decimating polyphase filter is to avoid wasted computation due to the discarding of samples. Decimation is the process of low-pass filtering (LPF) followed by downsampling, shown in Figure 1. The LPF minimizes aliasing coming from the discarding of samples from downsampling.

Why polyphase filter is used?

The polyphase FIR filter realization can provide advantages in computational efficiency when used for decimation or interpolation of discrete time signals.

What is polyphase decomposition in DSP?

Polyphase Decomposition. The multirate operations of decimation and interpolation that were introduced. in the previous section will now be used to decompose any system function. H(z) into its polyphase representation. Consider a discrete–time LTI system.