Patent attributes
A frequency measurement circuit includes a first counter that counts a pulse number of a reference clock signal and generates first count data, a second counter that counts a pulse number of a measurement target clock signal and generates second count data, a time-to-digital conversion circuit that generates first time difference data indicating a time difference between a first timing at which the first counter starts counting of the pulse number and a second timing at which the second counter starts counting of the pulse number, and second time difference data indicating a time difference between a third timing at which the first counter ends counting of the pulse number and a fourth timing at which the second counter ends counting of the pulse number, and a calculation circuit that performs calculation based on the second count data, the first time difference data, and the second time difference data and generates frequency data indicating a frequency of the measurement target clock signal.
