Abstract: A television receiver converts a television signal of a standard television system currently employed into a signal at a horizontal scanning frequency of n (an integer of 2 or more) times that of the original television signal, so that it can visually reproduce any one of a television signal of the standard television system and a television signal of a second television system, which has a horizontal scanning frequency of about n times that of the television signal of the standard television system. When receiving the television signal of the standard television system, the horizontal deflection circuit operates at a horizontal scanning frequency n times that of the standard television system. When receiving the television signal of the second television system, it operates at the horizontal scanning frequency of the second television system.

Abstract: A convergence circuit for use in a color television image display system comprising a modulator receiving at one input a first signal at the line frequency of the deflection circuit and at another input a second signal at the field frequency of the deflection circuit, a quadrant separator for separating the modulated signal into four sections in accordance with the polarity of the modulated signal and the respective first and second half periods of the field scan to generate four control currents corresponding respectively to the corners of a rectangular raster. The control currents are supplied through respectively adjustment potentiometers to a convergence coil to permit independent convergence of scanned points in the corners of the screen.

Abstract: Disclosed are a convergence device consisting of a circuit for generating a signal in synchronism with the horizontal sync signal and a circuit for generating a sinusoidal waveform current in response to the output signal from the signal generating circuit so that part of the sinusoidal waveform current may be used as a convergence correction or adjustment current, and a color television receiver incorporating the convergence device of the type described and capable of enlarging part of a picture.