| 摘要 |
PURPOSE:To reduce the transmission time delay with simple constitution by transmitting a control code pattern instead of a specific code pattern for a certain period of digital data and substituting the control code pattern with the specific code pattern in case of reception when the control code pattern is detected. CONSTITUTION:A signal (a) obtained by subjecting an analog signal 1 to A/D conversion in an A/D converter 2 is supplied to not only an adder 41 through a shift register 40 but also a specific pattern detecting circuit 42. The circuit 42 outputs a detection signal S1 of a specific code pattern X indicating a no-sound part in digital data. A specific code sequence signal b' where M series are continuous is generated from an M- series generating circuit 45 by a pulse signal S4 from a pulse generating circuit 44, and this signal is added to the signal (a) by the adder 41 to obtain scrambled data c'. A switch 46 is operated by an AND signal S3 between a pulse S2 from the circuit 44 and the signal S1, and a synchronizing code pattern Y' is sent from a synchronizing code generating circuit 47 while it is operated, and this pattern is modulated by a signal f' added to the signal c' and is transmitted. In case of reception, when the synchronizing code pattern is detected from the demodulated signal f', this pattern is substituted with the pattern X to obtain the signal (a), and the signal is subjected to D/A conversion. |
