| 摘要 |
This digital transmission system can automatically detect lag time. A test audio signal having an idiosyncratic pattern is generated at a point in time synchronized to a timing pulse, a video signal and the test audio signal are compressed, generating a TS signal, after encoding, an error or a unique code is inserted at points in time synchronized to a timing pulse having a predetermined interval, the received signal is demodulated and decoded, the error or unique code inserted at the predetermined interval is detected, the received TS signal is expanded, the video signal and test audio signal are output, the idiosyncratic pattern contained in the expanded test audio signal is detected, detection time difference information of the detection time of the idiosyncratic pattern contained in the expanded test audio signal and the detection time of the error or unique code is calculated by means of Reed-Solomon decoding, and the value resulting from adding a known lag signal in the transmission path encoding and digital modulation transmission is calculated as the lag time from input to reception-side output. |
