1// University of Florida EEL6528
2// Tan F. Wong
3// Feb 2, 2021
4
5#pragma once
6
7#include "fft.hpp"
8
9// Overlap-save filter class
10class FilterOverlapSave {
11 public:
12 FilterOverlapSave(int x_len, int h_len, std::complex<float>* h, int nt=1); // single-rate constructor
13 FilterOverlapSave(int up, int down, int x_len, int h_len, std::complex<float>* h, int nt=1); // multi-rate constructor
14 ~FilterOverlapSave(void); // destructor
15 int filter(std::complex<float>* in, std::complex<float>* out); //do filtering
16 void set_head(bool reset=false); // Set head of input array for continuously filtering
17 int out_len(void); //calculate output length
18
19 private:
20 void setup(int x_len, int h_len, std::complex<float>* h, int nt); // utility method to set up FFTs
21 int fftsize;
22 fft* fwdfft; // forward FFT
23 fft* invfft; // inverse FFT
24 int U; // upsampling factor
25 int D; // downsampling factor
26 int L; // length of filter impulse response
27 int M; // length of valid sample block
28 int nblocks; // number of blocks to calculate
29 int nthreads; // number of threads to use in FFT calculation
30 int nx; // length of input sequence
31 int Unx; // length of input sequence after interpolation
32 std::complex<float>* H; // FFT of impulse response
33};
34
35// Polyphase filter class
36class FilterPolyphase {
37 public:
38 FilterPolyphase(int up, int down, int x_len, int h_len, std::complex<float>* h, int nt); // constructor
39 ~FilterPolyphase(void); // destructor
40 int filter(std::complex<float>* in, std::complex<float>* out); // do filtering
41 void set_head(bool reset=false); // Set head of input array for continuously filtering
42 int out_len(void); //calculate output length
43
44 private:
45 int fftsize;
46 fft* fwdfft; // forward FFT
47 fft* invfft; // inverse FFT
48 int U; // upsampling factor
49 int D; // downsampling factor
50 int L; // length of filter impulse response
51 int Lp; // length of polyphase filter impulse responses
52 int M; // length of valid sample block
53 int nblocks; // number of blocks to calculate on each down-sampled input signal (row)
54 int nthreads; // number of threads to use in FFT calculation
55 int nx; // length of input sequence
56 int nxD; // length of down-sampled signals
57 std::complex<float>* F; // FFTs of impulse responses of polyphase filters
58};
