Decimating FIR Filter

Block: Decimating FIR Filter (dec_fir)
Block Author: Aaron Parsons
Document Author: Aaron Parsons, Ben Blackman

Contents

Summary
Mask Parameters
Ports
Description
- Usage

Summary

FIR filter which can handle multiple time samples in parallel and decimates down to 1 time sample. If coefficiencts are symmetric, it will automatically fold before multiplying.

Mask Parameters

Parameter	Variable	Description
Number of Parallel Streams	n_inputs	The number of time samples which arrive in parallel.
Coefficients	coeff	The FIR coefficients. If this vector is symmetric, the FIR will automatically fold before multiplying.
Bit Width Out	n_bits	The number of bits in each real/imag sample of the complex number that is output.
Quantization Behavior	quantization	The quantization behavior used in converting to the output bit width.
Add Latency	add_latency	The latency of adders/converters.
Mult Latency	mult_latency	The latency of multipliers.

Ports

Port	Dir	Data Type	Description
sync_in	IN	boolean	Takes an impulse 1 cycle before input is valid.
realX	IN	Fix_(n_bits)_(n_bits-1)	Real input X
inagX	IN	Fix_(n_bits)_(n_bits-1)	Imaginary input X
sync_out	OUT	boolean	Will be high the clock cycle before `dout` is valid.

Description

Usage

User specifies the number of parallel streams to be decimated to one complex number. Inputs are multiplied by the coefficients and added together to form dout. Bit Width Out specifies the widths of the real and imaginary components of the complex number to be output (Ex. if Bit Width Out = 8, then dout will be 16 bits, 8 for the real and imaginary components).