seiichi horie / Mbed 2 deprecated ifmag_noise_canceller

Experimental implementation of the adaptive filter of "Interface" magazine in 2016-2017

Dependencies:   amakusa mbed-dsp mbed shimabara ukifune unzen_nucleo_f746

Fork of skeleton_unzen_nucleo_f746 by seiichi horie

ハードウェアおよびソフトウェアはskelton_unzen_nucleo_f746を基本にしています。

vfo.cpp@18:b9b1116f8768, 2017-02-01 (annotated)

Committer:
shorie
Date:
Wed Feb 01 15:00:31 2017 +0000
Revision:
18:b9b1116f8768
Parent:
17:728ffc633179 
Update ciomment

Who changed what in which revision?

UserRevisionLine numberNew contents of line
shorie 14:cec63d8da48c 1 #include "signal_processing.h"
shorie 14:cec63d8da48c 2
shorie 18:b9b1116f8768 3
shorie 14:cec63d8da48c 4 VFO::VFO( void )
shorie 14:cec63d8da48c 5 {
shorie 14:cec63d8da48c 6 // initial parameter setting.
shorie 18:b9b1116f8768 7 this->form = triangle;
shorie 14:cec63d8da48c 8 this->Fs = 48000;
shorie 14:cec63d8da48c 9 this->frequency = 440;
shorie 14:cec63d8da48c 10 this->duty_cycle = 0.5;
shorie 16:d4ea3e6a0bce 11
shorie 16:d4ea3e6a0bce 12 this->update_parameters();
shorie 14:cec63d8da48c 13 } // End of constructor()
shorie 18:b9b1116f8768 14
shorie 18:b9b1116f8768 15 VFO::~VFO( void )
shorie 18:b9b1116f8768 16 {
shorie 18:b9b1116f8768 17 // do nothing
shorie 18:b9b1116f8768 18 }
shorie 14:cec63d8da48c 19
shorie 14:cec63d8da48c 20
shorie 18:b9b1116f8768 21
shorie 14:cec63d8da48c 22 void VFO::run(
shorie 14:cec63d8da48c 23 float out_buffer[], // vfo output buffer
shorie 14:cec63d8da48c 24 unsigned int block_size // block size [sample]
shorie 14:cec63d8da48c 25 )
shorie 14:cec63d8da48c 26 {
shorie 14:cec63d8da48c 27 // place the signal processing coce here
shorie 14:cec63d8da48c 28 for ( int i= 0; i< block_size; i++ )
shorie 14:cec63d8da48c 29 {
shorie 15:de22b9d147e0 30 // 1 : if phase < half_way; 0 : others.
shorie 18:b9b1116f8768 31 if ( this->form == square )
shorie 15:de22b9d147e0 32 {
shorie 15:de22b9d147e0 33 if ( this->current_phase < this->half_way )
shorie 16:d4ea3e6a0bce 34 out_buffer[i] = 1.0;
shorie 15:de22b9d147e0 35 else
shorie 15:de22b9d147e0 36 out_buffer[i] = 0.0;
shorie 15:de22b9d147e0 37 }
shorie 18:b9b1116f8768 38 else // form == triangle
shorie 16:d4ea3e6a0bce 39 {
shorie 16:d4ea3e6a0bce 40 if ( this->current_phase < this->half_way )
shorie 16:d4ea3e6a0bce 41 out_buffer[i] = this->rising_rate * this->current_phase;
shorie 16:d4ea3e6a0bce 42 else
shorie 16:d4ea3e6a0bce 43 out_buffer[i] = 1 + this->falling_rate * ( this->current_phase - this->half_way );
shorie 16:d4ea3e6a0bce 44 }
shorie 15:de22b9d147e0 45
shorie 15:de22b9d147e0 46 // update phase
shorie 15:de22b9d147e0 47 this->current_phase += this->frequency;
shorie 15:de22b9d147e0 48 // limit the range of the phase.
shorie 15:de22b9d147e0 49 if ( this->current_phase >= this->Fs )
shorie 15:de22b9d147e0 50 this->current_phase -= this->Fs;
shorie 14:cec63d8da48c 51 }
shorie 14:cec63d8da48c 52 } // End of run()
shorie 14:cec63d8da48c 53
shorie 14:cec63d8da48c 54
shorie 14:cec63d8da48c 55 void VFO::set_Fs( int Fs )
shorie 14:cec63d8da48c 56 {
shorie 14:cec63d8da48c 57 // regulate the Fs.
shorie 14:cec63d8da48c 58 if ( Fs != 32000 && Fs != 44100 && Fs != 96000 && Fs != 48000 )
shorie 14:cec63d8da48c 59 Fs = 48000;
shorie 14:cec63d8da48c 60 this->Fs = Fs;
shorie 16:d4ea3e6a0bce 61
shorie 16:d4ea3e6a0bce 62 this->update_parameters();
shorie 14:cec63d8da48c 63 }
shorie 14:cec63d8da48c 64
shorie 14:cec63d8da48c 65 void VFO::set_frequency( int freq )
shorie 14:cec63d8da48c 66 {
shorie 14:cec63d8da48c 67 if ( freq > this->Fs / 4 )
shorie 16:d4ea3e6a0bce 68 freq = Fs / 4;
shorie 14:cec63d8da48c 69 this->frequency = freq;
shorie 16:d4ea3e6a0bce 70
shorie 16:d4ea3e6a0bce 71 this->update_parameters();
shorie 14:cec63d8da48c 72 }
shorie 14:cec63d8da48c 73
shorie 14:cec63d8da48c 74 void VFO::set_duty_cycle( float duty )
shorie 14:cec63d8da48c 75 {
shorie 14:cec63d8da48c 76 if ( duty > 0.5f ) // high limit
shorie 14:cec63d8da48c 77 duty = 0.5f;
shorie 17:728ffc633179 78 if ( duty < 0.0f ) // low limit
shorie 17:728ffc633179 79 duty = 0.0f;
shorie 14:cec63d8da48c 80 this->duty_cycle = duty;
shorie 16:d4ea3e6a0bce 81
shorie 16:d4ea3e6a0bce 82 this->update_parameters();
shorie 14:cec63d8da48c 83 }
shorie 14:cec63d8da48c 84
shorie 18:b9b1116f8768 85 void VFO::set_wave_form( wave_form form )
shorie 14:cec63d8da48c 86 {
shorie 18:b9b1116f8768 87 this->form = form;
shorie 14:cec63d8da48c 88 }
shorie 14:cec63d8da48c 89
shorie 14:cec63d8da48c 90
shorie 16:d4ea3e6a0bce 91 // update the internal parameter by given parameters
shorie 16:d4ea3e6a0bce 92 void VFO::update_parameters(void)
shorie 16:d4ea3e6a0bce 93 {
shorie 16:d4ea3e6a0bce 94 // calc the half_way;
shorie 17:728ffc633179 95 this-> half_way = this->Fs * this-> duty_cycle;
shorie 16:d4ea3e6a0bce 96
shorie 16:d4ea3e6a0bce 97 // forbid to be zero.
shorie 16:d4ea3e6a0bce 98 if ( this-> half_way < this->frequency )
shorie 16:d4ea3e6a0bce 99 half_way = this->frequency;
shorie 16:d4ea3e6a0bce 100
shorie 16:d4ea3e6a0bce 101 // for triangle wave;
shorie 16:d4ea3e6a0bce 102 this->rising_rate = 1.0 / this->half_way;
shorie 16:d4ea3e6a0bce 103
shorie 16:d4ea3e6a0bce 104 this->falling_rate = - 1.0 / ( this->Fs - this->half_way );
shorie 16:d4ea3e6a0bce 105 }
shorie 16:d4ea3e6a0bce 106