Review of Polyphase FilteringTechnique in Signal Processing

The signals that are encountered in practice are mostly analog signals. These signals, which appear consistently in time and amplitude, are processed using active and passive circuit elements using a power network. This approach is known as the analog signal processing (ASP)-For example Radio and television communication. They may be processed using digital hardware, including adders, multipliers, and logic elements or any other special-purpose microprocessor. However, we needs to change these analog signals to the appropriate digital format such signal forms are called digital signals. The signals have noise which affects the quality of the signal. In this paper, poly-phase filter which can remove empty bands from the signal is reviewed.