公开(公告)号：JPS62204689A

公开(公告)日：1987-09-09

申请号：JP4801186

申请日：1986-03-05

Applicant: SONY CORP

Inventor： KAJITA MASAMI ,  YAMASHITA KEITARO

IPC: H04N9/793 ,  H04N9/79 ,  H04N9/83

Abstract: PURPOSE:To improve the S/N of a reproduced chrominance signal of a peripheral track by increasing/decreasing a recording current level of an FM chrominance signal in response to the center radius of a recording track on a magnetic disk. CONSTITUTION:A control data table corresponding to each track of a magnetic sheet disk D is stored in a ROM 2, position data of a magnetic head 2 is supplied from a system control circuit 5 and gain control data of a gain control amplifier 18C is read from a ROM 21. The gain control data is converted into an analog gain control signal by a D/A converter 22 and the gain of the amplifier 18C is controlled at each track. Thus, the recording current level of the FM chrominance signal CFM flowing to a head 2 is increased by nearly 2.5dB at the peripheral track based on the current level of the innermost circumferential track to suppress the relative spurious level to a prescribed value or below.