The MSM6722 converts in real-time the pitch of the speech signal in a range of one octave upward or downward. Two pitch control methods can be selected. One is to change the pitch in 17 steps by two switch inputs, and the other is to select one of 16 steps by four binary input lines. Since a microphone preamplifier and a low-pass filter are built in, the pitch conversion set can easily be configured by connecting a microphone, amplifier, and speaker in the peripheral circuit.