A linearizer circuit comprises a frequency mixer which mixes a first frequency varying in accordance with a change in a parameter and a second frequency from a reference oscillator which has no dependence upon any parameter at a given proportion, and a derivation circuit for producing an output pulse corresponding to the average period of an output from the mixer, thus providing a linearized output for the parameter. The linearizer circuit may be assembled into a watch as means to detect the environmental temperature of the watch. By detecting temperature information with this means, a temperature compensation of a clock signal may be achieved in accordance with a temperature offset from a reference temperature.