| 摘要 |
PROBLEM TO BE SOLVED: To maintain a high power level and reduced signal distortion and to attain a high data transmission rate by combining a sound vector signal and preencoded data signal and transmitting the combined signal. SOLUTION: An analog sound signal is encoded by a coder 101 and a sound vector signal and a digital sound control signal are generated. A first in first out(FIFO) buffer 102 multiplexes the sound control signal and an external digital data signal and supplies the multiplexed signal to a mapper 108 or the like. A preencoder 20 receives a signal from the mapper 108 as an input to a filter 22. A quantizer 26 generates a dither vector, restricts the size of the vector, reduces signal distortion, and outputs a signal X(n) capable of attaining data transmission with a higher power level. The signal X(n) is added to the sound vector signal outputted from the coder 101 and the added signal is transmitted to a receiving side MODEM through a modulator 117. |
