Circular AMDF and pitch estimation based on it

Pitch period is a key parameter in speech compression, synthesis and recognition. The well-known AMDF is often used to determine this parameter. But it is easy to make the estimated pitch doubled. With the problem, this paper analyses the features of the AMDF and its disadvantages that occur in pitch detection. And a new function, Circular AMDF (CAMDF), is proposed. The CAMDF conquers the defect of the AMDF effectively, and simplifies the process of pitch detection. With the properties of CAMDF, a new pitch detection algorithm based on CAMDF is described. The algorithm not only simplifies the pitch detection, but also efficiently decreases the estimation errors and improves the precision of estimated values. Lots of experiments show that the performance of the algorithm is better than other methods that are based on the AMDF or the LVAMDF.