qsinewavevalidator_p.h

Enable keyboard shortcuts

// Copyright (C) 2024 The Qt Company Ltd.

// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only

#ifndef QSINEWAVEVALIDATOR_H

#define QSINEWAVEVALIDATOR_H

//

//  W A R N I N G

//  -------------

//

// This file is not part of the Qt API. It exists purely as an

// implementation detail. This header file may change from version to

// version without notice, or even be removed.

//

// We mean it.

//

#include <array>

#include <QtCore/qtconfigmacros.h>

QT_BEGIN_NAMESPACE

// sine wave validator: accumulating peak value and result of passing the signal through a notch

// filter. A sine wave of that frequency should not pass the notch filter, so if the peak exceeds a

// small threshold, it we can detect discontinuities for example.

struct QSineWaveValidator

    QSineWaveValidator(const QSineWaveValidator &) = delete;

    QSineWaveValidator(QSineWaveValidator &&) = delete;

    QSineWaveValidator &operator=(const QSineWaveValidator &) = delete;

    QSineWaveValidator &operator=(QSineWaveValidator &&) = delete;

    QSineWaveValidator(float notchFrequency, float sampleRate);

    void feedSample(float sample);

    float peak() const { return accumPeak; }

    float notchPeak() const;

private:

    float a0, a1, a2;

    float b0, b1, b2;

    std::array<float, 3> x{}, y{};

    int framesBeforeAnalysis = 128; // unscientific estimate, larger than the transient response

                                    // time for the IIR filter

    int pendingFramesBeforeAnalysis = framesBeforeAnalysis;

    float accumPeak{};

    float accumNotchPeak{};

};

QT_END_NAMESPACE

#endif // QSINEWAVEVALIDATOR_H