Character generator comprising a startstop oscillator.

摘要

A character generator comprises a phase-coupled clock signal generator which is implemented as a start-stop oscillator (1) to which a line signal is applied. The clock frequency is dependent on an adjusting value (F). For adjusting and monitoring the clock frequency, the clock signal generator is provided with a counter (2). This counter counts the number of clock pulses occurring during a predetermined period and thus supplies a counting value (C). A control circuit (3) compares the counting value (C) with a reference value and adapts the adjusting value (F) in such a way that the oscillator frequency is within a predetermined range. Such a character generator is suitable for On Screen Display applications in a television receiver. <IMAGE>