| 摘要 |
<p>PURPOSE:To execute oscillation as well even at a higher harmonic of a crystal resonator by changing a feedback resistance value and a capacity value between the input of an inverter and a ground and between an output and the ground by the change over of a switch in addition to the oscillation by the fundamental wave of the crystal resonator. CONSTITUTION:Three resistors Rf1-Rf3, to which switches S1-S3 to be controlled by a decoder 3 are serially connected, are parallelly connected to an inverter 1 to which a crystal resonator 2 is parallelly connected. Then, between the input of the inverter 1 and the ground and between the output and ground, capacitors Cg1, Cg2, Cd1 and Cd2, to which switches S4-S7 to be controlled by a decoder 4 are serially connected, are parallelly connected respectively. When only the switch S1 is turned on among the switches S1-S3 and only the resistor Rf1 is parallelly connected to the inverter 1, this circuit is oscillated by the fundamental wave of the crystal resonator 2. Then, when the switches S1 and S2 are turned on, the feedback resistance value is smaller than the resistor Rf1 and a maximum value is obtained with the frequency of high negative resistance. Thus, the oscillation can be executed as well even at a higher harmonic in addition to the fundamental wave of the crystal resonator.</p> |
