| 摘要 |
The vertical raster correction circuit, for a television receiver, produces a parabolic signal from a sawtooth waveform. The sawtooth (20) is applied to both inputs of a multiplication stage and the parabolic waveform appears at the output (35, 36). The multiplier consists of two cross-coupled differential amplifiers (1-4) each of whose coupled emitters is controlled by the collector current of a further differential amplifier (7, 8). The emitter of the latter is coupled over a resistor (9, 10) to a constant dc source (11). The cross-coupled transistors are controlled in opposition by the voltage drop across a pair of transistors (29, 30) emitter resistors. |
