用c++实现

以下是一个简单的C++程序，演示如何使用Rx/0算法进行数字调制识别：

#include <iostream>
#include <vector>
#include <complex>
#include <cmath>

using namespace std;

// 定义数字调制方式和带宽的枚举类型
enum ModulationType { BPSK, QPSK, QAM16, QAM64 };
enum BandwidthType { Narrowband, Wideband };

// 定义数字调制方式和带宽的特征
struct ModulationFeature {
    double mainlobeWidth;  // 主瓣宽度
    double peakPower;      // 峰值功率
};

struct BandwidthFeature {
    double bandwidth;      // 带宽
};

// 定义数字调制识别器类
class ModulationRecognizer {
public:
    ModulationRecognizer() {
        // 初始化预定义的数字调制方式和带宽的特征
        modulationFeatures[BPSK] = { 1.0, 1.0 };
        modulationFeatures[QPSK] = { 1.0, 2.0 };
        modulationFeatures[QAM16] = { 2.0, 4.0 };
        modulationFeatures[QAM64] = { 4.0, 8.0 };

        bandwidthFeatures[Narrowband] = { 1.0 };
        bandwidthFeatures[Wideband] = { 2.0 };
    }

    // 识别数字调制方式和带宽
    void recognize(const vector<complex<double>>& signal, ModulationType& modulationType, BandwidthType& bandwidthType) {
        // 计算信号的功率谱密度
        vector<double> powerSpectrum = calculatePowerSpectrum(signal);

        // 提取信号的特征
        ModulationFeature modulationFeature = extractModulationFeature(powerSpectrum);
        BandwidthFeature bandwidthFeature = extractBandwidthFeature(powerSpectrum);

        // 比较信号的特征与预定义的特征，确定数字调制方式和带宽
        modulationType = compareModulationFeature(modulationFeature);
        bandwidthType = compareBandwidthFeature(bandwidthFeature);
    }

private:
    // 计算信号的功率谱密度
    vector<double> calculatePowerSpectrum(const vector<complex<double>>& signal) {
        int N = signal.size();
        vector<double> powerSpectrum(N);
        for (int i = 0; i < N; i++) {
            powerSpectrum[i] = abs(signal[i]) * abs(signal[i]);
        }
        return powerSpectrum;
    }

    // 提取信号的特征
    ModulationFeature extractModulationFeature(const vector<double>& powerSpectrum) {
        int N = powerSpectrum.size();
        double maxPower = 0.0;
        int maxPowerIndex = 0;
        for (int i = 0; i < N; i++) {
            if (powerSpectrum[i] > maxPower) {
                maxPower = powerSpectrum[i];
                maxPowerIndex = i;
            }
        }
        double mainlobeWidth = 0.0;
        for (int i = maxPowerIndex; i < N && powerSpectrum[i] >= 0.5 * maxPower; i++) {
            mainlobeWidth += 1.0;
        }
        for (int i = maxPowerIndex - 1; i >= 0 && powerSpectrum[i] >= 0.5 * maxPower; i--) {
            mainlobeWidth += 1.0;
        }
        double peakPower = maxPower / N;
        return { mainlobeWidth, peakPower };
    }

    BandwidthFeature extractBandwidthFeature(const vector<double>& powerSpectrum) {
        int N = powerSpectrum.size();
        double totalPower = 0.0;
        for (int i = 0; i < N; i++) {
            totalPower += powerSpectrum[i];
        }
        double halfPower = 0.5 * totalPower;
        double bandwidth = 0.0;
        double powerSum = 0.0;
        for (int i = 0; i < N; i++) {
            powerSum += powerSpectrum[i];
            if (powerSum >= halfPower) {
                bandwidth = i + 1;
                break;
            }
        }
        return { bandwidth };
    }

    // 比较信号的特征与预定义的特征，确定数字调制方式和带宽
    ModulationType compareModulationFeature(const ModulationFeature& modulationFeature) {
        double minDistance = INFINITY;
        ModulationType minModulationType;
        for (auto it = modulationFeatures.begin(); it != modulationFeatures.end(); it++) {
            double distance = pow(modulationFeature.mainlobeWidth - it->second.mainlobeWidth, 2) + pow(modulationFeature.peakPower - it->second.peakPower, 2);
            if (distance < minDistance) {
                minDistance = distance;
                minModulationType = it->first;
            }
        }
        return minModulationType;
    }

    BandwidthType compareBandwidthFeature(const BandwidthFeature& bandwidthFeature) {
        double minDistance = INFINITY;
        BandwidthType minBandwidthType;
        for (auto it = bandwidthFeatures.begin(); it != bandwidthFeatures.end(); it++) {
            double distance = pow(bandwidthFeature.bandwidth - it->second.bandwidth, 2);
            if (distance < minDistance) {
                minDistance = distance;
                minBandwidthType = it->first;
            }
        }
        return minBandwidthType;
    }

    // 预定义的数字调制方式和带宽的特征
    map<ModulationType, ModulationFeature> modulationFeatures;
    map<BandwidthType, BandwidthFeature> bandwidthFeatures;
};

int main() {
    // 生成一个BPSK信号
    int N = 1024;
    double f = 1000.0;
    double fs = 10000.0;
    vector<complex<double>> signal(N);
    for (int i = 0; i < N; i++) {
        signal[i] = complex<double>(cos(2.0 * M_PI * f * i / fs), 0.0);
    }

    // 使用数字调制识别器识别信号的数字调制方式和带宽
    ModulationRecognizer recognizer;
    ModulationType modulationType;
    BandwidthType bandwidthType;
    recognizer.recognize(signal, modulationType, bandwidthType);

    // 输出识别结果
    cout << "Modulation type: " << modulationType << endl;
    cout << "Bandwidth type: " << bandwidthType << endl;

    return 0;
}

该程序使用了STL库中的vector、map和复数类型，实现了数字调制识别器类ModulationRecognizer。程序首先生成一个BPSK信号，然后使用ModulationRecognizer识别信号的数字调制方式和带宽，并输出识别结果。在ModulationRecognizer类中，calculatePowerSpectrum函数计算信号的功率谱密度，extractModulationFeature和extractBandwidthFeature函数分别提取信号的数字调制方式和带宽的特征，compareModulationFeature和compareBandwidthFeature函数比较信号的特征与预定义的特征，确定数字调制方式和带宽。