| 摘要 |
PROBLEM TO BE SOLVED: To provide a voltage-controlled crystal oscillator that is able to adjust a variable amount characteristic at low cost and easily by means of an IC with a built-in varicap diode.SOLUTION: A voltage-controlled crystal oscillator comprises a crystal vibrator 1 and an IC including an inverter 21 connected in parallel with the crystal vibrator 1 and varicap diodes 26, 27 connected with both ends of the inverter 21, and the IC comprises: a trimming element 31 one end of which is connected with an anode side of the varicap diode 26 and the other end is grounded; and a trimming element 32 one end of which is connected with an anode side of the varicap diode 27 and the other end is grounded. By cutting off the trimming elements 31, 32, the built-in varicap diodes 26, 27 connected with them are invalidated, and by externally installing varicap diodes with a different characteristic instead, the voltage-controlled crystal oscillator is made to be able to adjust a frequency variable amount characteristic at low cost and easily. |
