FREQUENCY CORRECTION METHOD FOR DIGITAL CONTROL TYPE OSCILLATION CIRCUIT

• Main Authors: NONAKA YOJI, HIRAMOTO JUICHI, ISHIDA YUJI, SUWA YOJI
• Format: Patent
• Language: English
• Published: 07.06.1996
• Edition: 6
• Subjects: BASIC ELECTRONIC CIRCUITRY; ELECTRICITY; GENERATION OF NOISE BY SUCH CIRCUITS; GENERATION OF OSCILLATIONS, DIRECTLY OR BY FREQUENCY-CHANGING,BY CIRCUITS EMPLOYING ACTIVE ELEMENTS WHICH OPERATE IN ANON-SWITCHING MANNER

PURPOSE: To provide the frequency correction method of a digital control type oscillation circuit for improving frequency accuracy by dividing the control voltage of a varactor diode used for temperature compensation into plural sections and controlling it. CONSTITUTION: In this frequency correction method of the digital control type oscillation circuit 60 for correcting the change of the resonance frequency of a crystal oscillator due to temperature change by adjusting the control voltage of the varactor diode and outputting a fixed frequency, frequency deviation characteristics for the control voltage of the varactor diode are divided into appropriate plural control sections beforehand, the frequency deviations of the respective control sections are expressed by the linear expression of the control voltage and respective linear coefficients and the temperature characteristics of the crystal oscillator are stored in a memory 67. The frequency deviation is calculated from the temperature characteristics of the crystal oscillator corresponding to a temperature detected by a temperature sensor 62, the control voltage of the varactor diode is obtained and outputted by using the linear coefficient of the corresponding control section and thus, an output frequency is controlled to a prescribed fixed frequency.