Speech pitch detection is a feature with many uses such as speaker diarization and speech activity detector. The use of average magnitude difference function (AMDF) is prevalent in RTOS’s due to its low complexity. A natural alternative to the AMDF is the magnitude average product function (MAPF).
Suppose the received signal at the microphone is given as:
where is the desired speech signal and is i.i.d zero mean Gaussian noise. The MAPF algorithm proceeds on a frame by frame basis. Suppose a frame of length N is available,such that . Then the AMDF function is defined as:
A smoother version, which we utilize, is the binarized bMAPF which is defined as:
The pitch is found using:
A smoothening function can be applied to to remove spurious noise. A sample performance of AMDF is shown in Figure 1 below:
Figure 1: Pitch detection in speech using bMAPF
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