alexbrandmeyer@609: //
alexbrandmeyer@609: //  agc_params.cc
alexbrandmeyer@609: //  CARFAC Open Source C++ Library
alexbrandmeyer@609: //
alexbrandmeyer@609: //  Created by Alex Brandmeyer on 5/10/13.
alexbrandmeyer@609: //
alexbrandmeyer@609: // This C++ file is part of an implementation of Lyon's cochlear model:
alexbrandmeyer@609: // "Cascade of Asymmetric Resonators with Fast-Acting Compression"
alexbrandmeyer@609: // to supplement Lyon's upcoming book "Human and Machine Hearing"
alexbrandmeyer@609: //
alexbrandmeyer@609: // Licensed under the Apache License, Version 2.0 (the "License");
alexbrandmeyer@609: // you may not use this file except in compliance with the License.
alexbrandmeyer@609: // You may obtain a copy of the License at
alexbrandmeyer@609: //
alexbrandmeyer@609: //     http://www.apache.org/licenses/LICENSE-2.0
alexbrandmeyer@609: //
alexbrandmeyer@609: // Unless required by applicable law or agreed to in writing, software
alexbrandmeyer@609: // distributed under the License is distributed on an "AS IS" BASIS,
alexbrandmeyer@609: // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
alexbrandmeyer@609: // See the License for the specific language governing permissions and
alexbrandmeyer@609: // limitations under the License.
alexbrandmeyer@609: 
alexbrandmeyer@609: #include "agc_params.h"
alexbrandmeyer@609: 
alexbrandmeyer@610: // The default constructor for AGCParams initializes with the settings from
alexbrandmeyer@610: // Lyon's book 'Human and Machine Hearing'
alexbrandmeyer@610: AGCParams::AGCParams() {
alexbrandmeyer@609:   n_stages_ = 4;
alexbrandmeyer@626:   agc_stage_gain_ = 2.0;
alexbrandmeyer@626:   std::vector<FPType> base_values = {1.0, 1.4, 2.0, 2.8};
alexbrandmeyer@626:   FPType agc1_factor = 1.0;
alexbrandmeyer@611:   FPType agc2_factor = 1.65;
alexbrandmeyer@609:   time_constants_.resize(n_stages_);
alexbrandmeyer@611:   agc1_scales_.resize(n_stages_);
alexbrandmeyer@611:   agc2_scales_.resize(n_stages_);
alexbrandmeyer@611:   for (int i = 0; i < n_stages_; ++i) {
alexbrandmeyer@626:     time_constants_[i] = pow(4, i) * 0.002;
alexbrandmeyer@626:     // TODO (alexbrandmeyer): check with Dick Lyon about best way to initialize.
alexbrandmeyer@626:     // Tests on AGC values fail the equality test with Matlab when using the
alexbrandmeyer@626:     // geometric method for initializing the AGC scales.
alexbrandmeyer@626:     // agc1_scales_[i] = agc1_factor * pow(2.0, i/2.0);
alexbrandmeyer@626:     // agc2_scales_[i] = agc2_factor * pow(2.0, i/2.0);
alexbrandmeyer@626:     agc1_scales_[i] = agc1_factor * base_values[i];
alexbrandmeyer@626:     agc2_scales_[i] = agc2_factor * base_values[i];
alexbrandmeyer@611:   }
alexbrandmeyer@610:   decimation_ = {8, 2, 2, 2};
alexbrandmeyer@609:   agc_mix_coeff_ = 0.5;
alexbrandmeyer@626: }