| 摘要 |
PURPOSE:To prevent the fluctuation of an oscillating frequency due to temperature change by providing a temperature sensor and a memory, comparing the temperature at preceding and this operation for each intermittent operation, and stopping the intermittent operation of a phase locked loop at reception when a prescribed temperature change or over is recognized. CONSTITUTION:When a PLL is locked in intermittently and a voltage controlled oscillator VCO is subject to free run at a point of time of the synchronization is obtained, if a rapid temperature change exists, the oscillating frequency of the VCO not PLL-locked is fluctuated due to temperature. Then intermittent temperature detection is applied in a temperature detection comparison block, the temperature of preceding PLL lock-in and the temperature at present are compared. When there is a prescribed difference or over in the both, the PLL loop is not interrupted but the lock-in state is kept over a period to be received continuously. Thus, the fluctuation in the oscillating frequency due to a temperature change is suppressed. |
