view trunk/carfac/agc_params.cc @ 678:7f424c1a8b78

Fifth revision of Alex Brandmeyer's C++ implementation of CARFAC. Moved output structure to deque<vector<FloatArray>, moved coefficient Design methods to CARFAC object, moved tests into carfac_test.cc. Verified binaural output against Matlab using two tests. Added CARFAC_Compare_CPP_Test_Data to plot NAP output of C++ version against Matlab version. Verified build and test success on OS X using SCons with g++ 4.7 (std=c++11).

//
//  agc_params.cc
//  CARFAC Open Source C++ Library
//
//  Created by Alex Brandmeyer on 5/10/13.
//
// This C++ file is part of an implementation of Lyon's cochlear model:
// "Cascade of Asymmetric Resonators with Fast-Acting Compression"
// to supplement Lyon's upcoming book "Human and Machine Hearing"
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#include "agc_params.h"

// The default constructor for AGCParams initializes with the settings from
// Lyon's book 'Human and Machine Hearing'
AGCParams::AGCParams() {
  n_stages_ = 4;
  agc_stage_gain_ = 2.0;
  time_constants_.resize(n_stages_);
  agc1_scales_.resize(n_stages_);
  agc2_scales_.resize(n_stages_);
  agc1_scales_[0] = 1.0;
  agc2_scales_[0] = 1.65;
  time_constants_[0] = 0.002;
  for (int i = 1; i < n_stages_; ++i) {
    agc1_scales_[i] = agc1_scales_[i - 1] * sqrt(2.0);
    agc2_scales_[i] = agc2_scales_[i - 1] * sqrt(2.0);
    time_constants_[i] = time_constants_[i - 1] * 4.0;
  }
  decimation_ = {8, 2, 2, 2};
  agc_mix_coeff_ = 0.5;
}