The invention relates to a method for implementing a multistage FIR filter in the field of an
integrated circuit. The method for implementing the multistage FIR filter relates to an arithmetic unit, a
control unit and a
software environment for conducting
programming configuration on the
control unit. The arithmetic unit comprises a pretreatment unit, an ALU and a storage unit RAM, a
transfer function of the filter is calculated through
time division multiplexing, the mode that data in the RAM are flexibly read by changing addresses is adopted, and therefore a large quantity of data transfer
power consumption in a typical filter implementation method is saved. The
control unit comprises a storage unit ROM and a plurality of counters and summing units, commands and coefficients in the
transfer function of the filter are provided for the arithmetic unit, therefore, filtering arithmetic of the arithmetic unit is finished in specific control step-by-step numbers, and a filtering result is acquired. The
software environment conducts the
programming configuration on the control unit according to performance parameters of the filter, and therefore a custom-made FIR filter suitable for application requirements is acquired. The method for implementing the multistage FIR filter can be mainly used for achieving a multistage FIR
decimation filter, a multistage FIR interpolation filter and a multistage FIR same-speed filter, the function that the area can reach the minimum level of documents which have been published internationally can be achieved, and the method for implementing the multistage FIR filter has the advantages of greatly reducing the
power consumption and customizing products according to the application requirements.