| 摘要 |
<P>PROBLEM TO BE SOLVED: To solve the problems wherein deviation is generated in an output frequency of DPLL by a temperature characteristic of TCXO3 for supplying a reference signal of the DPLL at the application time of power of a receiving device in SS demodulation of a GPS received signal, and when searching for a synchronous point by tracking the frequency of an SS modulated wave fluctuating by a Doppler shift, capture of the synchronous point requires a long time because of generation of out-of-synchronism or the like. <P>SOLUTION: Data of a center frequency of the TCXO3, a frequency offset quantity at a reference temperature, and the maximum frequency changing rate of the TCXO3 when the temperature is changed at the rate of 1°C per second are stored in a memory 31 of the TCXO3. At the operation start time of the receiving device, the data stored in the memory 31 of the TCXO3 are read and stored in a memory 7 by a CPU 6. The center frequency and the frequency offset quantity from inside the data are set in a fractional synthesizer 42, and the maximum frequency changing rate is set as clock synchronous pulling-in speed of the DPLL 54. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
