Abstract: Waveform data written in a RAM 2 base on write addresses is always read out as two waveform data from two read addresses 1 and 2 designated by a CPU 1, and two interpolation data 1 and 2 are formed. A smaller address difference A between the write address and the read address 1 is multiplied with the interpolation data 1 as an envelope value to obtain cross-fade data 1. Similarly, cross-fade data 2 corresponding to the read address 2 is obtained. The two items of cross-fade data 1 and 2 are added to each other to obtain output waveform data. An envelope value of waveform data near a waveform discontinuous point becomes almost zero, and click noise can be eliminated.

Abstract: A CPU measures the interval between the zero-crossing points at the two ends of a waveform element a having, e.g., a positive polarity. Thereafter, the CPU sequentially measures the interval between the zero-crossing points at the two ends of each of waveform elements b, c, and d having the same polarity. Upon detection of the waveform element d which is almost equal in interval to the waveform element a and is located nearest thereto in terms of time, the interval between the start points (zero-crossing points) of the waveform elements a and d is extracted as the pitch period of the input waveform. Subsequently, the above-described series of operations is repeated.

Abstract: A voice input to a microphone is converted by an A/D converter to a digital signal which is then delivered to a DSP, which extracts the notes of the input voice for determining same. The processing by the DSP includes bandpass filtering with a frequency corresponding to each note as the central frequency. A plurality of notes is processed on a time divisional basis to determine their respective notes. A new musical sound electronically corresponding to one or more notes extracted as the result of the note detection is then generated on a real time basis.