view src/Modules/SNR/ModuleNoise.h @ 94:cbe78255b12c

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// Copyright 2010, Thomas Walters
//
// AIM-C: A C++ implementation of the Auditory Image Model
// http://www.acousticscale.org/AIMC
//
// 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.

/*!
 * \author Thomas Walters <[e-mail]>
 * \date created 2010/02/24
 * \version \$Id$
 */

#ifndef AIMC_MODULES_SNR_NOISE_H_
#define AIMC_MODULES_SNR_NOISE_H_

#include <boost/random.hpp>

#include "Support/Module.h"

namespace aimc {
class ModuleNoise : public Module {
 public:
  explicit ModuleNoise(Parameters *pParam);
  virtual ~ModuleNoise();

  /*! \brief Process a buffer
   */
  virtual void Process(const SignalBank &input);

 private:
  /*! \brief Reset the internal state of the module
   */
  virtual void ResetInternal();

  /*! \brief Prepare the module
   *  \param input Input signal
   *  \param output true on success false on failure
   */
  virtual bool InitializeInternal(const SignalBank &input);

  float sample_rate_;
  int buffer_length_;
  int channel_count_;

  // True to generate pink noise, otherwise white noise
  bool pink_;

  // Filter state variables
  float s0_;
  float s1_;
  float s2_;

  float multiplier_;

  // Mersenne twister random number generator fed into a transform which 
  // yeilds Gaussian-distributed values
  boost::variate_generator<boost::mt19937,
                           boost::normal_distribution<float> >
                           gaussian_variate_;
};
}  // namespace aimc

#endif  // AIMC_MODULES_SNR_NOISE_H_