| 摘要 |
<p>PHASE LOCKED LOOP CIRCUIT Phase locked loop (PLL) circuit comprises, a phase detector including first and second cascadeconnected differential pairs of transistors constituting an analog multiplier with each one of the differential pair transistors supplied with two inputs, a low pass filter for converting the detection output into a D.C. control voltage, and an emitter-coupled multivibrator including constant current sources for determining the oscillation frequency with a timing capacitor. The PLL circuit is provided with constant current adjusting means for variably setting or determining the current through a constant current source connected to the second differential pair of transistors and the currents through the current sources determining the oscillation frequency in a correlated manner through a common variable resistor. Thereby, dispersions in the loop gain of the PLL circuit are reduced.</p> |
