| 摘要 |
Frequency synthesizer employing a current mirror circuit having a control branch which includes a transistor (T1) which is supplied by a control current source (S) operating in the switch mode. An improved decay time of the current mirror circuit is obtained by providing an additional transistor (TA) in parallel with the transistor (T1), having a fixed base bias voltage such that transistor (TA) is practically cut off when the control current source (S) supplies a nominal current and starts conducting when the control current is switched off. If the additional transistor (TA) is bipolar it is provided with an anti-saturation device, for example, a Schottky diode (18). It may, however, be a field effect transistor.
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