| 摘要 |
PURPOSE:To make it possible to lower the price while simplifying this circuit by reducing local oscillation crystal by adding or subtracting a constant number to or from a control signal through a logic circuit and then by applying the converted control signal to a program counter. CONSTITUTION:Control signal N of PLL is added or subtracted by logical operation circuit BC to vary the output frequency of PLL without varying local oscillation frequency f1. As a result, an arithmetic process can be carried out by an arithmetic instruction signal through logical operation circuit BC, and consequently only one crystal for local oscillation is required, so that the circuit can be simplified. |
