RECORD PLAYER WITH AUTOMATIC MUSIC SEARCH FUNCTION

摘要

A record player is equipped with a tonearm control which enables the record player to perform an automatic music search, that is, the pickup device of the tone arm may be automatically controlled to be set down at the beginning of a selected song. It may happen that the center of the record is slightly displaced from the center of the turntable, so that different angular segments of the recorded tracks lie at different radial distances from the turntable center. The present tonearm control compensates for this by detecting the radial and angular position of the beginning of the selected song and by setting down the pickup device at this position. The radial position of the beginning of each song is measured along a radial reference detection line while the turntable is at rest at an initial angular position. Then, while the turntable is rotating, the tone arm is moved across the record until the pickup device reaches the measured radial position of the beginning of the selected song. The angular position of the turntable relative to its initial position is detected, and the tone arm control determines the moment of set down so that the record rotates just enough to bring the reference detection line to the angular position of the pickup device. Therefore, the pickup device is set down at the angular position on the record at which the radial position of the beginning of the song was measured. The result is that play starts at the beginning of the song even when the eccentricity of the record causes the tracks to be off center.