1 /* Copyright 2018 The TensorFlow Authors. All Rights Reserved.
2 
3 Licensed under the Apache License, Version 2.0 (the "License");
4 you may not use this file except in compliance with the License.
5 You may obtain a copy of the License at
6 
7     http://www.apache.org/licenses/LICENSE-2.0
8 
9 Unless required by applicable law or agreed to in writing, software
10 distributed under the License is distributed on an "AS IS" BASIS,
11 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 See the License for the specific language governing permissions and
13 limitations under the License.
14 ==============================================================================*/
15 #ifndef TENSORFLOW_LITE_EXPERIMENTAL_MICROFRONTEND_LIB_PCAN_GAIN_CONTROL_UTIL_H_
16 #define TENSORFLOW_LITE_EXPERIMENTAL_MICROFRONTEND_LIB_PCAN_GAIN_CONTROL_UTIL_H_
17 
18 #include "tensorflow/lite/experimental/microfrontend/lib/pcan_gain_control.h"
19 
20 #define kWideDynamicFunctionBits 32
21 #define kWideDynamicFunctionLUTSize (4 * kWideDynamicFunctionBits - 3)
22 
23 #ifdef __cplusplus
24 extern "C" {
25 #endif
26 
27 struct PcanGainControlConfig {
28   // set to false (0) to disable this module
29   int enable_pcan;
30   // gain normalization exponent (0.0 disables, 1.0 full strength)
31   float strength;
32   // positive value added in the normalization denominator
33   float offset;
34   // number of fractional bits in the gain
35   int gain_bits;
36 };
37 
38 void PcanGainControlFillConfigWithDefaults(
39     struct PcanGainControlConfig* config);
40 
41 int16_t PcanGainLookupFunction(const struct PcanGainControlConfig* config,
42                                int32_t input_bits, uint32_t x);
43 
44 int PcanGainControlPopulateState(const struct PcanGainControlConfig* config,
45                                  struct PcanGainControlState* state,
46                                  uint32_t* noise_estimate,
47                                  const int num_channels,
48                                  const uint16_t smoothing_bits,
49                                  const int32_t input_correction_bits);
50 
51 void PcanGainControlFreeStateContents(struct PcanGainControlState* state);
52 
53 #ifdef __cplusplus
54 }  // extern "C"
55 #endif
56 
57 #endif  // TENSORFLOW_LITE_EXPERIMENTAL_MICROFRONTEND_LIB_PCAN_GAIN_CONTROL_UTIL_H_
58