Abstract: A rotary head type digital signal recording and/or reproducing apparatus wherein for 1/2 speed recording and/or reproducing from a magnetic tape, a tape feed speed is decreased to 1/2 times the normal speed, and a recording/reproducing interval becomes 2 times that of the normal mode of operation utilizing at least two rotary heads mounted at adjacent positions on a rotating cylinder with one of the rotary heads having a plus azimuth angle and the other having a minus azimuth angle. For 2 times speed recording/reproducing, a tape feed speed increases to 2 times the normal speed, and a recording/reproducing interval becomes 1/2 that of the normal mode of operation utilizing at least two rotary heads mounted on a rotating cylinder at opposite positions of a rotary axis of the cylinder, with one of the two rotary heads having a plus azimuth angle and the other having a minus azimuth angle.

Abstract: 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.

Abstract: A detector circuit for detecting a phase or frequency error of an input signal. One mode of at least two detection modes is selected according to a phase or a frequency of the input signal with each mode having a reference value of a phase or a frequency of the input signal and reference values of the detection modes being different from each other. A pulse signal having a phase corresponding to a difference between an actual phase or frequency of the input signal and the reference value of the phase or the frequency is generated, and a predetermined carrier signal is pulse width modulated with a predetermined modulation factor in response to the pulse signal, the modulation factor being different for each detection mode.