不韋 呂 / Mbed 2 deprecated SDR_FM_Rx_CIC

AM中波放送用SDR．CICフィルタのみを使用．CQ出版社「トランジスタ技術」誌，2021年5月号に掲載

Dependencies:   mbed

main.cpp@1:2b596eab04de, 2021-02-04 (annotated)

Committer:
MikamiUitOpen
Date:
Thu Feb 04 09:45:09 2021 +0000
Revision:
1:2b596eab04de
Parent:
0:4037028ba61a
Child:
2:fa94a6a917dd
2

Who changed what in which revision?

UserRevisionLine numberNew contents of line
MikamiUitOpen 0:4037028ba61a 1 //-------------------------------------------------------------
MikamiUitOpen 0:4037028ba61a 2 // FM 用 SDR
MikamiUitOpen 0:4037028ba61a 3 // 入力信号：SDR_FM_Tx で発生した信号
MikamiUitOpen 0:4037028ba61a 4 // 入力ピン： A1
MikamiUitOpen 0:4037028ba61a 5 // 出力ピン： A2
MikamiUitOpen 0:4037028ba61a 6 // ダウンサンプリングで CIC フィルタを使用
MikamiUitOpen 0:4037028ba61a 7 //
MikamiUitOpen 0:4037028ba61a 8 // Tera Term から選局可能，0 と 1
MikamiUitOpen 0:4037028ba61a 9 //
MikamiUitOpen 1:2b596eab04de 10 // 2021/02/04, Copyright (c) 2021 MIKAMI, Naoki
MikamiUitOpen 0:4037028ba61a 11 //-------------------------------------------------------------
MikamiUitOpen 0:4037028ba61a 12
MikamiUitOpen 0:4037028ba61a 13 #include "F446_ADC_Intr.hpp"
MikamiUitOpen 0:4037028ba61a 14 #include "F446_DAC.hpp"
MikamiUitOpen 0:4037028ba61a 15 #include "QuadOscIir.hpp"
MikamiUitOpen 0:4037028ba61a 16 #include "Cic3Stage.hpp"
MikamiUitOpen 0:4037028ba61a 17 #include "FastATan.hpp"
MikamiUitOpen 0:4037028ba61a 18 #include "IirDcCut.hpp"
MikamiUitOpen 0:4037028ba61a 19 #include "InitialMessage.hpp" // 最初のメーッセージ
MikamiUitOpen 0:4037028ba61a 20 using namespace Mikami;
MikamiUitOpen 0:4037028ba61a 21 #pragma diag_suppress 870 // マルチバイト文字使用の警告抑制のため
MikamiUitOpen 0:4037028ba61a 22
MikamiUitOpen 0:4037028ba61a 23 const float FS_ = 900.0f; // 標本化周波数，単位： kHz
MikamiUitOpen 0:4037028ba61a 24 const float T0_ = 1000/FS_; // 標本化間隔，単位：μs
MikamiUitOpen 0:4037028ba61a 25 const float A0_ = 8192; // 直交信号発生器の出力の振幅
MikamiUitOpen 0:4037028ba61a 26
MikamiUitOpen 0:4037028ba61a 27 const float F_C_[] = { 70.0e3f, 130.0e3f}; // 搬送波周波数
MikamiUitOpen 0:4037028ba61a 28
MikamiUitOpen 0:4037028ba61a 29 AdcF446_Intr adc_(FS_, A1);
MikamiUitOpen 0:4037028ba61a 30 DacF446 dac_;
MikamiUitOpen 0:4037028ba61a 31 Serial pc_(USBTX, USBRX); // ターミナルに対する受信割込み用
MikamiUitOpen 1:2b596eab04de 32
MikamiUitOpen 0:4037028ba61a 33 // 直流分除去用フィルタ
MikamiUitOpen 0:4037028ba61a 34 // 高域通過フィルタ
MikamiUitOpen 0:4037028ba61a 35 // バタワース特性
MikamiUitOpen 0:4037028ba61a 36 // 次数　　　　： 1 次
MikamiUitOpen 0:4037028ba61a 37 // 標本化周波数： 36.00 kHz
MikamiUitOpen 0:4037028ba61a 38 // 遮断周波数　： 0.05 kHz
MikamiUitOpen 0:4037028ba61a 39 IirDcCut dcCut_(9.913112E-01f, 9.956556E-01f); // 入力の直流成分除去用フィルタ
MikamiUitOpen 0:4037028ba61a 40
MikamiUitOpen 0:4037028ba61a 41 QuadOscIir nco_(F_C_[0], T0_, A0_); // NCO (numerically controlled oscillator)
MikamiUitOpen 0:4037028ba61a 42
MikamiUitOpen 0:4037028ba61a 43 const int DS_RATE_ = 25; // 1/25 にダウンサンプリング
MikamiUitOpen 0:4037028ba61a 44 Cic3Stage cic3I_(DS_RATE_, A0_);
MikamiUitOpen 0:4037028ba61a 45 Cic3Stage cic3Q_(DS_RATE_, A0_);
MikamiUitOpen 0:4037028ba61a 46
MikamiUitOpen 0:4037028ba61a 47 // AD 変換終了割り込みに対する割り込みサービス･ルーチン
MikamiUitOpen 0:4037028ba61a 48 void AdcIsr()
MikamiUitOpen 0:4037028ba61a 49 {
MikamiUitOpen 0:4037028ba61a 50 static int count = 0;
MikamiUitOpen 0:4037028ba61a 51
MikamiUitOpen 0:4037028ba61a 52 float xn = adc_.Read(); // ADC の読込み
MikamiUitOpen 0:4037028ba61a 53 float sinX, cosX;
MikamiUitOpen 0:4037028ba61a 54 nco_.Generate(sinX, cosX); // sin, cos 発生
MikamiUitOpen 0:4037028ba61a 55
MikamiUitOpen 0:4037028ba61a 56 cic3I_.Integrate((int16_t)(xn*cosX)); // I 信号
MikamiUitOpen 0:4037028ba61a 57 cic3Q_.Integrate((int16_t)(xn*sinX)); // Q 信号
MikamiUitOpen 0:4037028ba61a 58
MikamiUitOpen 0:4037028ba61a 59 if (++count >= DS_RATE_)
MikamiUitOpen 0:4037028ba61a 60 {
MikamiUitOpen 0:4037028ba61a 61 count = 0;
MikamiUitOpen 0:4037028ba61a 62 NVIC->STIR |= EXTI4_IRQn; // ソフトウェア割り込み発生
MikamiUitOpen 0:4037028ba61a 63 }
MikamiUitOpen 0:4037028ba61a 64 }
MikamiUitOpen 0:4037028ba61a 65
MikamiUitOpen 0:4037028ba61a 66 // ダウンサンプラより後の処理に対する割り込みサービス･ルーチン
MikamiUitOpen 0:4037028ba61a 67 void SwiIsr()
MikamiUitOpen 0:4037028ba61a 68 {
MikamiUitOpen 0:4037028ba61a 69 static const float PI = 3.141592654;
MikamiUitOpen 0:4037028ba61a 70 static const float PI2 = 2.0f*PI;
MikamiUitOpen 0:4037028ba61a 71 static float phi_nM1 = 0; // 一つ前の位相の値
MikamiUitOpen 0:4037028ba61a 72
MikamiUitOpen 0:4037028ba61a 73 float yI_n = cic3I_.CombFilter(); // くし形フィルタ処理で I 信号を生成
MikamiUitOpen 0:4037028ba61a 74 float yQ_n = cic3Q_.CombFilter(); // くし形フィルタ処理で Q 信号を生成
MikamiUitOpen 0:4037028ba61a 75
MikamiUitOpen 0:4037028ba61a 76 float phi_n = FastATan(yQ_n, yI_n); // 位相成分を求める
MikamiUitOpen 0:4037028ba61a 77 float dif = phi_n - phi_nM1; // 位相の差分
MikamiUitOpen 0:4037028ba61a 78 if (dif > PI) dif -= PI2; // 差分処理の補正
MikamiUitOpen 0:4037028ba61a 79 if (dif < -PI) dif += PI2; // 差分処理の補正
MikamiUitOpen 0:4037028ba61a 80
MikamiUitOpen 0:4037028ba61a 81 float yn = dcCut_.Execute(dif); // 直流分除去
MikamiUitOpen 0:4037028ba61a 82 dac_.Write(yn);
MikamiUitOpen 0:4037028ba61a 83 phi_nM1 = phi_n;
MikamiUitOpen 0:4037028ba61a 84 }
MikamiUitOpen 0:4037028ba61a 85
MikamiUitOpen 0:4037028ba61a 86 // シリアル･ポートの受信割込みに対する処理
MikamiUitOpen 0:4037028ba61a 87 void RxIsr()
MikamiUitOpen 0:4037028ba61a 88 {
MikamiUitOpen 0:4037028ba61a 89 unsigned char chr = pc_.getc();
MikamiUitOpen 0:4037028ba61a 90 // 受信した文字が '0', '1' の場合のみ NCO の周波数を変える
MikamiUitOpen 0:4037028ba61a 91 if (('0' <= chr) && (chr <= '1'))
MikamiUitOpen 0:4037028ba61a 92 {
MikamiUitOpen 0:4037028ba61a 93 nco_.Set(F_C_[chr & 0x01]);
MikamiUitOpen 0:4037028ba61a 94 pc_.putc(chr); // エコーバック
MikamiUitOpen 0:4037028ba61a 95 }
MikamiUitOpen 0:4037028ba61a 96 if (chr == '\r') pc_.printf("\r\n");
MikamiUitOpen 0:4037028ba61a 97 }
MikamiUitOpen 0:4037028ba61a 98
MikamiUitOpen 0:4037028ba61a 99 int main()
MikamiUitOpen 0:4037028ba61a 100 {
MikamiUitOpen 0:4037028ba61a 101 InitialMessage("ダウンサンプリングに CIC フィルタ使用．", FM, pc_);
MikamiUitOpen 0:4037028ba61a 102
MikamiUitOpen 0:4037028ba61a 103 NVIC_SetPriority(ADC_IRQn, 0); // 最優先
MikamiUitOpen 0:4037028ba61a 104 NVIC_SetPriority(EXTI4_IRQn, 1); // ２番目に優先
MikamiUitOpen 0:4037028ba61a 105 NVIC_SetPriority(USART2_IRQn, 2); // ３番目に優先
MikamiUitOpen 0:4037028ba61a 106
MikamiUitOpen 0:4037028ba61a 107 adc_.SetIntrVec(&AdcIsr); // ADC の割り込みサービス･ルーチンの設定
MikamiUitOpen 0:4037028ba61a 108
MikamiUitOpen 0:4037028ba61a 109 // EXTI4 によるソフトウェア割り込みに対応する設定
MikamiUitOpen 0:4037028ba61a 110 NVIC_SetVector(EXTI4_IRQn, (uint32_t)SwiIsr);
MikamiUitOpen 0:4037028ba61a 111 NVIC_EnableIRQ(EXTI4_IRQn);
MikamiUitOpen 0:4037028ba61a 112
MikamiUitOpen 0:4037028ba61a 113 // シリアル･ポートの受信割込みの設定
MikamiUitOpen 0:4037028ba61a 114 pc_.format(); // default: 8 bits, nonparity, 1 stop bit
MikamiUitOpen 0:4037028ba61a 115 pc_.attach(&RxIsr);
MikamiUitOpen 0:4037028ba61a 116
MikamiUitOpen 0:4037028ba61a 117 while (true) {}
MikamiUitOpen 0:4037028ba61a 118 }