| 摘要 |
PURPOSE:To facilitate the easy designing of the filter by providing the bias means to the low pass filter to be connected to the phase comparator in which the output is opened when the phase coincidence is obtained between the reference oscillation signal and the voltage control oscillation signal. CONSTITUTION:When the phase of 2 inputs has an agreement to each other, the output is opened for phase comparators 1. This output is supplied to the base of transistor Q1 via resistance R1. The emitter of Q1 is connected to the base of Darlington-connected Q2 via diode 5. In other words, the base of Q1 features about 2.4V when the output of comparator 1 is opened to become the intermediate level of the output levels between H and L of comparator 1. Resistance R2 and capacitor C2 are used for the filter, and the output is extracted out of the collectors of Q2 and Q3. |
