US Patent 7929381 Time information obtaining apparatus and radio timepiece

A signal composing circuit 12 receives a signal including a time code from a receiving circuit 10, and detects input waveform data of a unit time length, whose value at ach sampling point is given by a value expressed in plural bits. The input waveform data is accumulated. CPU 13 calculates a minimum position on a time axis, where the minimum value of the accumulated input waveform data is given and a maximum gradient position on the time axis, where a difference between values of the accumulated input waveform data at adjacent sampling points is maximum, and further calculates a leading position of a unit time length of the signal including the time code.