Abstract: Time delay can’t be avoided between reference audio signal and test signal in the audio quality evaluation named PEAQ，especially which is employed for monitoring online audio system.Calculating the time delay and making time alignment between reference audio signal and test signal is very important for audio quality evaluation in audio coding，audio system and audio communication.To deal with the problem mentioned above，the article presents a real-time and efficient time delay algorithm by calculating audio envelope，frequency spectrum cross correlation and histogram.When this algorithm is applied in the broadcast audio monitoring system，it shows the characteristic of real-time，steady and highly active.

Key words: time delay, time alignment, objective quality assessment, audio quality

摘要： 在音频质量客观评价（Perceptual Evaluation of Audio Quality，PEAQ）尤其是音频系统的在线评测时，参考信号与测试信号不可避免地存在系统延迟。计算参考与测试之间的延迟误差从而实现信号之间的时间同步将是影响音频质量客观评价结果的关键性问题。针对此问题，通过信号的包络求取、信号频域间的互相关及频域直方图等方法给出了一种实时高效的音频延迟算法。通过实际测量，该算法在广播音频质量在线监测系统中充分体现了实时、稳定和高效的特点。

关键词: 时间延迟, 时间同步, 客观质量评价, 音频质量