Abstract: A power supply in which a single variable voltage supply device is used as a power source for a plurality of motors which are simultaneously or successively rotated, in which each motor is subjected to constant current driving by a current control device connected to the motor, and in which the variable voltage supply device is controlled so as to produce a voltage which is the sum of the highest one of the voltages required for driving the motors and necessary and minimum voltage with which all the current control devices are operable.

Abstract: A motor driving circuit in which the opposite ends of the motor driving coils of a video tape recorder (VTR) capstan motor are shorted by a group of switching elements when a control input voltage generated from a rotation detection/oscillator is in a predetermined range.

Abstract: A signal voltage dividing circuit in which two switched capacitors each including an input terminal, an output terminal and a capacitor connected selectively to the input terminal or the output terminal are connected in series and driven in opposite phase with each other. A holding capacitor is connected between the junction of the two switched capacitors and a reference potential. An input signal is supplied across the two switched capacitors to produce a divided output signal from the junction of the two switched capacitors.

Abstract: A control device for phase-locking a rotating or traveling member to a reference signal within a short time at its starting stage, in which a phasic error signal produced as a result of comparison of the phases of the reference signal and a signal representative of the phasic position of the member is fed to the driver of the member through a gate which is non-conductive unless the speed of motion of the member reaches a predetermined value.

Abstract: A servo circuit is disclosed for a video tape recorder of helical scan type having two rotary heads, in which recording/reproduction is capable of being performed at different tape feed rates, and a recording track for the video signal is formed partially superimposed on the previously-formed recording track, thus forming a recording track narrower than the heads when the tape feed rate is low. A control pulse which is in phase with the vertical synchronizing signal extracted from the video signal to be recorded is recorded in the control track, and the rotational phase of the rotary heads is controlled by use of the control pulse read at the time of reproduction. The servo circuit causes a shift in the phase of the control pulses and a change in the phase of the control pulses before recording when the tape feed rate is low.