Howtosignalprocessing
- How do poly phase filtering save computations in decimation filter?
- How does a polyphase filter work?
- What is polyphase interpolation filter?
- Why polyphase filter is used?
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.
How does a polyphase filter work?
A polyphase filterbank uses the DFT (discrete fourier transform) to modulate (move in frequency) a prototype filter and perform summation, effectively returning multiple bands of decimated and filtered time-domain data from the DFT stage. The DFT operation is typically performed using the FFT (fast fourier transform).
What is polyphase interpolation filter?
With the modified implementation, the input samples to the filter is clocked at the original sampling rate of . However, we need to have additional circuitry to dynamically load the coefficients and latch the output at the upsampled frequency . These filtersets are called polyphase filters.
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.
