Electronic stringed instrument

DETAILED DESCRIPTION It is, therefore, an object of the present invention to provide an electronic stringed instrument for accurately detecting a position of a fret with which a string depressed by a player's finger is in contact.
It is another object of the present invention to provide an electronic stringed instrument having a short response time for producing a musical tone.
In order to achieve the above objects of the present invention, there is provided an electronic stringed instrument comprising: an instrument body; a string which is stretched above the instrument body; a plurality of metal frets which are provided on the instrument body and below the string so that a player's depression of the string causes contact between the string and one or ones of the plurality of metal frets; ultrasonic transmitting/receiving means, provided on the instrument body and coupled to a specific point of the string, for generating an ultrasonic wave so that the ultrasonic wave is propagated through the string toward the nearest fret to the specific point among the fret or frets contacting the string and for receiving an echo wave which is a reflected wave of the ultrasonic wave from the nearest fret; and fret discriminating means connected to the ultrasonic transmitting/receiving means for discriminating the nearest fret among the plurality of metal frets according to a time difference between generation of the ultrasonic wave and the receipt of the echo wave and for generating a fret signal representing the nearest fret.
The present invention is based on an assumption that a propagation time of an ultrasonic wave to be propagated through a string is proportional to a string length.
An ultrasonic transmitting/receiving means intermittently transmits an ultrasonic wave.
The ultrasonic wave propagates from one end to the other end of the string.
When the player wishes to produce a specific musical tone and depresses a predetermined position of the string, the string is brought into contact with at least one of the plurality of frets so that a string length is defined by this fret