To improve reproduction quality of audio or music contained in digital audio data without causing excessive data or data loss in a data receiving circuit when the data receiving circuit is out of synchronization with a data transmitting circuit.

A period measurement unit 1 uses a high-speed sampling clock fsr in synchronization with a reception LR clock LRr and having a prescribed frequency higher than a frequency of the reception LR clock LRr to measure a period of a transmission LR clock LRs at prescribed time intervals. A data interpolation unit 2 calculates a period difference between the measured period of the transmission LR clock LRs and a period of the reception LR clock LRr. Then, at each of output timings of the reception LR clock LRr, the data interpolation unit 2 calculates a phase of the transmission LR clock LRs at each of the output timings based on the calculated period difference and linearly interpolates audio data Da before and after each of the output timings based on the calculated phase, to generate interpolated audio data Dinsr.