Digital temperature compensation crystal oscillator

Abstract

Abstract PURPOSE:To improve the C/N and to make the titled oscillator suitable for large scale circuit integration by allowing each charge/discharge circuit to output an analog signal while the impedance of each transistor (TR) switch element is changed timewise consecutively. CONSTITUTION:Charge/discharge circuits 28-31 each consist of a capacitor 40 and a resistor 41, a terminal 38 is connected to a serial/parallel converter 19 and a terminal 39 is connected to a gate of switch elements 24-27. Since only a gate of a MOS TR switch element is connected to the terminal 39 and the impedance of the gate is very high, it is regarded that a nearly infinite impedance is connected. That is, the charge/discharge circuits 28-31 constituting LPFs are inserted between the serial/parallel converter 19 and the switch elements 24-27 to suppress the sudden change in the oscillated frequency. Thus, the deterioration of the C/N is prevented, the oscillator is suitable for large scale circuit integration and an oscillation output with high purity is obtained.

Inventors

• 👤 Toshiyuki Nishihara
• 👤 壽之 西原

Bibliographic Details