Patent ID: 6292066
Filing Date: 2001-09-18
Classification: G06G,H03B,H03L

Abstract:
A function generator comprising:a first analog signal generating circuit for generating and outputting a predetermined analog signal substantially independent of an ambient temperature;a second analog signal generating circuit for generating and outputting an analog signal dependent upon the ambient temperature;storage means for storing control information respectively corresponding to first, second, third, fourth and fifth temperature regions obtained by dividing a feasible range of the ambient temperature into five continuous parts in this order along a direction from a low temperature to a high temperature;a third analog signal generating circuit for receiving said signal from said first analog signal generating circuit and said signal from said second analog signal generating circuit and further receiving said control information from said storage means, and for generating and outputting first, second, third, fourth and fifth control signals respectively corresponding to said five temperature regions; anda control circuit for receiving said first through fifth control signals and generating to output a control signal as a function of a temperature based on each received signal,wherein said storage means stores as said control information:a first proportional value defining a relationship between a proportional coefficient between a temperature used for generating said first control signal and the output value thereof and a cubic coefficient of a temperature characteristic of an oscillation frequency of a quartz oscillator;a second proportional value defining a relationship between a constant between a temperature used for generating said second control signal and the output value thereof and said cubic coefficient;a third proportional value defining a relationship between a proportional coefficient between a temperature used for generating said third control signal and the output value thereof and said cubic coefficient;a fourth proportional value defining a relationship between a constant between a temperature used for generating said fourth control signal and the output value thereof and said cubic coefficient; anda fifth proportional value defining a relationship between a proportional coefficient between a temperature used for generating said fifth control signal and the output value thereof and said cubic coefficient, andwherein when the ambient temperature is in any of said first, second and third temperature regions, said control signal outputted from said control circuit comprises: any of said first, second and third control signals which is selected by said control circuit; and another signal generated by altering said selected signal so as to form a smooth curve in a region around a border between the temperature region to which the ambient temperature belongs and the adjacent temperature region,while when the ambient temperature is in either of said fourth and fifth temperature regions, said control signal outputted from said control circuit comprises: any of at least one of said first, second and third control signals including said third control signal, said fourth control signal and said fifth control signal which is selected by said control circuit; and another signal generated by altering said selected signal so as to form a smooth curve in a region around a border between the temperature region to which the ambient temperature belongs and the adjacent temperature region.