Patent ID: 9154139
Filing Date: 2015-10-06
Classification: H03L

Abstract:
1. A crystal controlled oscillator, comprising: an oscillator circuit for oscillator output, being connected to a crystal unit for oscillator output; a first oscillator circuit and a second oscillator circuit, being connected to respective first crystal unit and second crystal unit for temperature detection; a heating unit, being configured to uniform an atmosphere temperature where each of the crystal units is placed; a pulse generator and a frequency difference detector, assume that an oscillation frequency of the first oscillator circuit is f1, an oscillation frequency of the first oscillator circuit at a reference temperature is f1r, an oscillation frequency of the second oscillator circuit is f2, and an oscillation frequency of the second oscillator circuit at the reference temperature is f2r, the pulse generator being configured to output a pulse at a time point where one of the f1 and the f2 latches another f1 or f2, the frequency difference detector being configured to obtain a direct current voltage corresponding to a difference value between a value corresponding to a difference between f1 and f1r and a value corresponding to a difference between f2 and f2r with phase locked loop based on a train of the pulses, as a temperature detection value; an addition unit, being configured to take out a deviation between a temperature setting value of atmosphere temperature where the first and the second crystal units are placed and the temperature detection value; a circuit unit, being configured to control heating electric power that controls electric power supplied to the heating unit based on the deviation taken out at the addition unit; a frequency measuring unit, being configured to measure a frequency in a set period at the train of pulses; a determination unit, being configured to determine whether the frequency measured by the frequency measuring unit is included in a detection range, out of the detection range at a high temperature side, or out of the detection range at a low temperature side; and a signal selector configured to: select a control signal where electric power supplied to the heating unit is smaller than supplied electric power in the detection range in a case where a frequency in a set period at the train of pulses is out of the detection range at the high temperature side; select a control signal where electric power supplied to the heating unit becomes a preset value in a case where a frequency in the set period at the train of pulses is out of the detection range at the low temperature side.