import { AbstractSoundChannel } from './abstract-sound-channel';
import { Audio, EventSource } from '../audio';
export declare class QuadrangularChannel extends AbstractSoundChannel {
    private _waveDuty;
    private _frequency;
    private hasFrequencySweep;
    private frequencySweepEnabled;
    private frequencySweepTimer;
    private frequencySweepShadow;
    private frequencySweepPeriod;
    private frequencySweepShift;
    private frequencySweepDirection;
    private _volume;
    private volumeSweepEnabled;
    private volumeSweepTimer;
    private volumeSweepLength;
    private volumeSweepDirection;
    private soundLengthEnabled;
    private soundLengthCounter;
    constructor(audio: Audio, eventSource: EventSource, registerMasks: number[], hasFrequencySweep: boolean);
    reset(): void;
    tick(sequencerCounter: number): void;
    frequency: number;
    volume: number;
    waveDuty: number;
    nrx0: number;
    nrx1: number;
    nrx2: number;
    nrx3: number;
    nrx4: number;
    private trigger();
    private updateFrequency();
    private updateVolume();
    private updateSoundLength();
    private sweepFrequency(saveChange);
}
export declare const WAVE_DUTY_MAP: number[];