| 摘要 |
PURPOSE:To scan correctly a rotary head by recording sound signals to be frequency-modulated having different carrier frequencies on a magnetic recording medium at every 1-track scanning period and obtaning track shift information from the reproducing level of sound signals to be frequency-modulated which are reproduced as crosstalks from a track to be scanned by the rotary head in both cases of recording and reproducing. CONSTITUTION:The 4th FM sound signal reproduced as a crosstalk from an adjacent track t4 is supplied to an FM demodulator 32 after it is selected in terms of frequency by a band-pass filter 28 and, on the other hand, impressed upon the inversional input terminal of a differential amplifier 51 through a changeover switch 50 after the sound signal is converted into a DC voltage corresponding to its reproduced FM level through a switching circuit 53 and level detecting circuit 48. When a rotary head HA1 runs while shifting to another track t6 side in 1-track scanning period, the level of FM sound signal reproduced from the crosstalk of the track t6 becomes relatively higher than the level of the FM sound signal reproduced from the crosstalk of the track t4 in accordance with the shifted quantity. Therefore, FM sound signals which are higher in level in accordance with the track shift are obtained at the output terminal 52 of the differential amplifier 51 in comparison with the normal reproducing time when no track shift occurs. |
