Abstract: A ghost cancelling reference signal transmission/reception system, which allows a built-in ghost cancelling device to eliminate group-delay distortion, frequency-amplitude characteristic distortion, ghost components generated in a signal transmission path. A digital signal is superposed on a television signal in a vertical blanking period of the television signal as a ghost cancelling reference signal.

Abstract: A teletext decoder having a character pickup circuit superior in the antinoise property and response characteristic by allowing signals only in the vicinity of clock run-in signals to pass, simultaneously detecting the amplitude of clock run-in signals through a band-pass filter circuit, gating framing code signals and reproduced clock and slice data, and integrating and holding the clock run-in signals.

Abstract: A sampling clock reproducing circuit which reproduces the sampling clock for sampling character data signals from the teletext signal superposed on the vertical blanking period of television signal, which has a gate for passing signals in the vicinity of clock run-in signals, a band-pass filter, a self-excited oscillator, phase comparison circuits for comparing the band-pass filter with the self-excited oscillator in the phase of output thereof, and an oscillation output circuit comprising a phase-shift circuit controlled by the outputs of the phase comparison circuits.

Abstract: A multiple display control apparatus for a television receiver used for displaying a plurality of signals on a display tube. In a case of switching a first signal output and a second signal output of a signal process circuit are switched by switching circuits, when the two output signals are about equal in the brightness level to each other, the picture is very indistinct. Thus, the first signal level is lowered by means of gain control circuits, the characteristic thereof depending on an output impedance of the signal process circuit and resistances. The control signals for switching and gain control are superposed each other as one signal, so that only one line is used for control signal.