| 摘要 |
PURPOSE:To minimize a frequency change at the time of compensation by selecting the up-and-down counting and counting stopping condition of a counter by a size relation of the compensating data and the output of the counter in a detected temperature. CONSTITUTION:When a temperature detecting circuit 1 detects a temperature T1, an address 6 corresponding to T1 is outputted and compensating data DT1 in the T1 are outputted by a memory 2. When the temperature detected previously is T0, the compensating data in the T0 are DT0 and DT0<DT1 is obtained, an up-down control signal 17 comes to be the signal of the up-counting mode. When the number of the bits of the output of the memory 2 is M, the number of the bits of a counter 4 is L, M=L-2, DT0=DT1-1 is obtained and four clocks are inputted for the counter 4, an output comes to be equal to the compensating data DT1 and the signal 18 makes a counter action into a stopping mode. Even at the time of DT0>LT1, LT0=UT1, in the same way as the above- mentioned, signals 17 and 18 are set to a prescribed mode. Thus, the frequency change at the time of the compensation can be minimized.
|
