| 摘要 |
PURPOSE:To perform temperature compensation for output frequency, by providing a storage circuit storing the reference data to set the output frequency to an objective value and correcting this reference date according to the temperature. CONSTITUTION:A storage circuit M is rewritable by closing a switch S, the switch S is opened when the output frequency from a terminal phi is coincident with an objective frequency, and frequency dividing data of variable frequency dividers D1-D3 at this time is written in the storage circuit M. Temperature detecting amount from a resistor R1 and a thermister R0 is digital-converted at an AD conversion circuit CV, the outputs A-D are applied to a decoder DE and designated outputs a-h for correction amount are obtained according to an average temperature characteristic of a quartz oscillator Q. A pulse generating circuit PG produces a correction pulse according to the outputs a-h, a counter PC makes addition/subtraction of the frequency dividing data and the correction pulse, and the frequency dividing ratio of the variable frequency dividers D1-D3 can be set from the result of operation. |
