| 摘要 |
PCT No. PCT/GB87/00860 Sec. 371 Date May 31, 1989 Sec. 102(e) Date May 31, 1989 PCT Filed Dec. 1, 1987 PCT Pub. No. WO88/04498 PCT Pub. Date Jun. 16, 1988.A duplex data transmission system in which a station can vary its transmission power to keep the signal-to-noise ratio the same in each direction or, in a system employing a different data rate in each direction, to keep the two ratios in a fixed relation to one another. In an initial training sequence, each station measures "talker echo" from its own transmission, and subsequently measures noise from the other station's transmission. The other station then makes the same measurements. The noise data thus collected is sent by both to a control circuit in one or other station which calculates from both sets of data an adjustment (e.g. a reduction) of the power to be transmitted. One or other stations then accordingly reduces power. |
