ENCODER/DECODER

PURPOSE:To minimize the deterioration of transmitting quality of sounds, by assigning a part of the encoded bit of a sound encoder to data signal transmission and simultaneously transmitting sounds and data. CONSTITUTION:At a transmission side, when a pattern generator 1 repeatedly outputs a specific pattern signal for a prescribed number of times, a mode switching signal C is sent to an encoder 2 and the encoder 2 encodes sound signals after the 2nd encoding rule. Then a multiplexing circuit 5 sends the encoded sound signals outputted from the encoder 2 after adding 1-bit data signals to the sound signals. On the other hand, the pattern detector 3 at a receiving side successively inputs signals at specific bit positions outputted from a separating circuit 6 and compares the signals with a previously fixed specific pattern. When coincidence of a prescribed number or more is detected, the detector 3 outputs the mode switching signal C to a decoder 4. The decoder 4 decodes the received signals into sound signals after a decoding rule designated by the signal supplied from the detector 3 and outputs the decoded sound signals after separating the 1-bit data signals.