摘要 |
PCT No. PCT/GB93/02163 Sec. 371 Date Nov. 29, 1994 Sec. 102(e) Date Nov. 29, 1994 PCT Filed Oct. 20, 1993 PCT Pub. No. WO94/09572 PCT Pub. Date Apr. 28, 1994A power transmission network which includes an input for the input of telecommunication signals having carrier frequencies greater than 1 MHz onto the network, and removing similar speech and/or data signals from the network. Preferably a network conditioning element is used which includes a low pass filter portion for filtering out a low frequency high amplitude mains power signal, and a coupling element for input and/or removal of telecommunication signals from the network. In this way both speech and data signals can be transmitted at carrier frequencies of greater than 1 MHz along a standard electricity distribution and/or transmission network which when conditioned provides a larger available spectrum per unit length of network and greater transmission capacity than previously known. The quiescent noise level of the conditioned network is also much reduced thus permitting lower signal injection levels for a given signal-to-noise ratio and a consequential reduction in spurious radiation from the network.
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