Electronic musical instrument in which musical tones are generated on the basis of pitches extracted from an input waveform signal

Claims

What is claimed is:

1. An electronic string musical instrument of a type in which musical tones are generated on the basis of pitches extracted from an input waveform signal produced by the vibration of a string, comprising:

pitch extracting means for extracting pitches from the input waveform signal;

input signal check means for checking whether said input waveform signal is present; and

commanding means (a) for, when said input signal check means detects a start of the presence of said input waveform signal, providing a sounding start command to first generate a musical tone with a predetermined pitch corresponding to maximum string length in which no pitch designation operation is manipulated on an open string by a performer and (b) for, when the pitch of said input waveform signal is extracted by said pitch extracting means, providing a command to change the pitch of said generated musical tone to the extracted pitch.

2. The electronic string musical instrument according to claim 1, in which said pitch extracting means comprises:

peak detecting means for detecting at least one of a positive and a negative peak point in the input waveform signal;

zero-cross point detecting means for detecting zero-cross points in said input waveform signal; and

means for detecting at least one of a time interval (t1) between successive first zero-cross points detected by said zero-cross point detecting means after after respective ones of the positive peak points are detected by said peak point detecting means and a time interval (t2) between successive first zero-cross points detected by said zero-cross point detecting means after respective ones of the negative peak points are detected by said peak point detecting means.

3. An electronic musical instrument of a type in which musical tones are generated on the basis of pitches contracted from an input waveform signal comprising:

detecting means for, upon initiation of said input waveform signal, detecting two periods of said input waveform signal within a time duration shorter than two periods of said input waveform signal; and

commanding means for when the two periods detected by said detecting means are substantially equal to each other, providing a command to initiate generation of a musical tone at a frequency whose period corresponds to a period of the input waveform signal derived from at least one of the two detected periods of the input waveform signal.

4. The electronic musical instrument according to claim 3, in which said detecting means detects said two periods by detecting a time duration (t1) between successive first zero-cross points appearing after respective positive peak points of said input waveform signal that are detected, and by detecting a time duration (t2) between successive first zero-cross points appearing after respective negative peak points of said input waveform signal that are detected.

5. The electronic musical instrument according to claim 3, in which said detecting means detects said two periods by detecting a time interval (T1) at which positive peak points appear and by detecting a time interval (T2) at which negative peak points appear.

6. An electronic string musical instrument of a type in which musical tones are generated on the basis of pitches extracted from signals produced by the vibrations of strings comprising:

detecting means for detecting, when inputting of said input waveform signal is initiated, whether a rate of increase of peak values of the input waveform signal is steep or gentle;

commanding means for, when said detecting means detects a gentle rate of increase of peak values of the input waveform signal, not providing a musical tone sounding command, and when said detecting means detects a steep rate of increase of peak values of the input waveform signal, providing a musical tone sounding command; and

wherein said detecting means detects the steep or gentle rate of increase of the input waveform signal by using at least one of (a) a difference between and (b) a ratio of a previously detected peak value of said input waveform signal and a presently detected peak value of the input waveform signal.

7. The electronic string musical instrument according to claim 6, further comprising pitch extracting means for extracting a pitch data from said input waveform signal, said pitch extracting means comprising:

peak detecting means for detecting at least one of a positive and a negative peak point in the input waveform signal;

zero-cross point detecting means for detecting zero-cross points in said waveform signal; and

means for detecting at least one of a time interval (t1) between successive first zero-cross points detected by said zero-cross point detecting means after respective positive peak points are detected by said peak point detecting means and a time interval (t2) between successive first zero-cross points detected by said zero-cross point detecting means after respective negative peak points are detected by said peak point detecting means.

8. An electronic string musical instrument of a type in which musical tones are generated on the basis of pitches extracted from input waveform signals produced by the vibrations of strings, comprising:

detecting means for detecting positive and negative peak points of the input waveform signal;

measuring means for measuring a time interval in a manner that successively obtained positive and negative peak points of said input waveform signal occurring immediately after inputting of said input waveform signal is initiated are obtained, and the absolute values thereof are compared, and the peak point or a point relating to the peak point of a larger value is used as a starting point of said time interval, and an end point of said time interval is the peak point or a point relating to a peak point which is the same polarity as that of the peak point used as the starting point, and satisfies a predetermined condition; and

commanding means for giving a command to generate a musical tone at a frequency based on said time interval measured by said measuring means.

9. The electronic string musical instrument according to claim 8, in which the point relating to said peak point is a zero-cross point following said peak point having the same polarity as that of the starting peak point.

10. The electronic string musical instrument according to claim 8, in which the point relating to said peak point is a zero-cross point immediately before said peak point having the same polarity as that of the starting peak point.

11. An electronic musical instrument of a type in which musical tones are generated on the basis of pitches extracted from an input waveform signal comprising:

first measuring means for measuring a given time period of one wave length of said input waveform signal;

second measuring means for measuring a given time period of one wave length partially overlapping said one wave length as measured by said first measuring means;

third measuring means for measuring a given time period of one wave length partially overlapping said one wave length as measured by said second measuring means;

judging means for judging whether the given time periods measured by said first to third measuring means are substantially equal to one another; and

commanding means for, when said given time periods are substantially equal, providing a command to change the frequency of a generated musical tone based on said given time periods as measured by said first to third measuring means after the musical tone is generated.

12. An electronic string musical instrument of a type in which musical tones are generated on the basis of pitches extracted from input waveform signals produced by the vibration of strings, comprising:

detecting means for detecting a variation of peak values in said input waveform signal; and

commanding means for, when said detecting means detects a rapid increase of a peak value of said input signal waveform during sounding of a musical tone, repeating a command to start the sounding of said musical tone.

13. The electronic string musical instrument according to claim 12, in which said detecting means detects a rapid increase of said input waveform signal based on (a) a difference between