| 摘要 |
A timebase generator includes a transistor switch performing a sweep gate function, alternately providing a current path for retrace and then disconnecting such current path to allow generation of a time base ramp. The bias current delivered to the switch is controlled to be at a high level for bringing about proper retrace, but at a low level at the beginning and ending of the time base sweep itself to prevent undesired transients and nonlinearity effects. The low current is maintained from the end of the retrace period until the start of the following retrace period. A baseline stabilizer loop comprises a transistor circuit for accurately predetermining the baseline reference wherein the emitter current of the transistor is controlled to a substantially constant value during operation for enhanced stability. The undesirable effect produced by inherent capacitance of a semiconductor device current source used for charging the timebase generator timing capacitor is neutralized by means of a matching semiconductor device interposed between the timebase generator output and an input electrode of the first mentioned semiconductor device. |
