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.

Abstract: A half tone reproducing circuitry in a facsimile system characterized by circuitry for pulse number modulating the image signal of an image including half tone circuitry for eliminating those pulses from the pulse frequency modulated signal occurring during the white portion of the image signal and circuitry for on and off controlling an image recording device by the modulated signal thereby reproducing the half tone of the image.