Frequency ratio measurement device

A frequency ratio measurement device that outputs a delta-sigma modulated signal corresponding to a frequency ratio of a first signal and a second signal, the frequency ratio measurement device comprising:

• a counter section;
• a time to digital converter section;
• a combiner section;
• a subtractor section;
• a quantizer section;
• and
• a feedback section, wherein
• the counter section counts a time event of the first signal and outputs a count value obtained by multiplying the time event by k0, where k0 is a rational number,
• the time to digital converter section outputs a time digital value corresponding to a phase difference between the first signal and the second signal,
• the combiner section outputs a combined value of the count value and the time digital value,
• the subtractor section outputs a difference value between a first value based on the combined value and a second value output from the feedback section,
• the quantizer section compares a third value based on the difference value with a predetermined threshold to thereby output a quantized value obtained by quantizing the third value,
• the feedback section outputs, based on a time event of the second signal, the second value based on the quantized value, and
• the delta-sigma modulated signal is a signal based on the quantized value.