VHS-improved reproduction by using active phase shift

With an active phase shift circuit, a video playback system for VHS has been created that guarantees a dramatic improvement in picture quality while keeping full compatibility. By the active control of phase shifting, the original upper sideband of the recorded FM signal, which normally can hardly be measured during playback is recovered. The main function of the circuit is the recovery of the high carrier frequencies, which will result in increased sharpness in the video signal. The second important function of the circuit is its series resonant circuit, which forms a bandpass. It is either damped or increased depending on the FM level. Thus, an automatic adaptation to the cassette quality can be realized