Digital temperature compensation crystal oscillator

Abstract

Abstract PURPOSE:To block a bit frequency fluctuation in a short period designated especially for a generating period of a burst signal by providing a means blocking a change in a temperature compensation signal corresponding to temperature compensation information. CONSTITUTION:A temperature sensor 1 detects an ambient temperature of a crystal vibrator of a voltage controlled crystal oscillator (VCX0)8. Data compensating the frequency temperature characteristic of the VCX08 is read from a ROM 6 and supplies it to a D/A converter 7. The output voltage of the D/A converter 7 is fed to the VCX08 to vary the capacitance of a varactor diode built in the VCX08 thereby controlling the oscillating frequency of the VCX08. When control information is inputted from a voltage holding circuit control input terminal 4, the voltage holding circuit 3 holds the output voltage of a temperature-voltage conversion circuit 2 for the period to block the change in the voltage applied to the VCX08. Thus, while the change is blocked by the means, the hit frequency fluctuation of the radio wave during transmission is prevented.

Inventors

• 👤 Koichi Sakuma
• 👤 孝一 佐久間

Bibliographic Details