U.S. Philips Corporation

Alfred Schaumberger

Arthur Heller

Klaus Schuster

Friedrich Gierlinger

Friedrich Dollinger

A method of producing a modulated chrominance signal with suppressed carrier. A square-wave carrier signal and a color information signal in the form of a sequence of digitally encoded amplitude values are applied to a modulator arrangement. The clock frequency for the amplitude values is an integral multiple of the color carrier frequency and is phase-locked thereto. Each bit of the amplitude values is inverted during one half cycle of the carrier and not inverted in the subsequent half cycle. A first and a second value, respectively are added to the values obtained thus, these first and second values being calculated such that also for input and/or output signal values which are located at a distance from the drive mean values at the input and output ends a total carrier suppression is achieved for the desired input signal level. The modulated analog chrominance signal is available after digital-to-analog conversion.

Method of producing a modulated chrominance signal with suppressed

A television test line signal generator comprising a read-only memory which is read under the control of a clocked counting circuit, memory outputs being connected via a clocked buffer store to a digital-to-analogue converter, which is followed by a signal filter. The information in the read-only memory is programmed versus signal distortions following thereafter.

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Olching, Germany

Alfred Schaumberger