Head switching signal producing circuit for a magnetic recording and reproducing apparatus

摘要

In a helical scanning type video tape recorder provided with two rotary video heads for recording and reproducing a video signal supplied to the heads in the oblique direction of a magnetic tape by alternately switching the two rotary video heads, there is generated a switching signal for the heads which is stable in standard and high speed reproducing modes and thereby stable reproduction always can be obtained. For this purpose, there are provided a circuit for detecting the rotary phase of any one of the two rotary heads, a clock signal generator circuit for generating a clock signal, a counter apparatus for counting the clock signal on the basis of the output of the rotary phase detecting circuit, and a circuit for generating a switching signal for alternately switching the two heads on the basis of the counted value of the counter apparatus.