| 摘要 |
<p>A remote control system utilizing spread-spectrum techniques. The system is particularly suitable for control of electrical wiring devices in a building and/or appliances. A spread-spectrum radio transmitter may be arranged to provide digital address and command information encoded according to a predetermined information code, to provide a preamble preceding this information encoded according to a preamble code different from the information code and to impress the encoded preamble and information on a radio-frequency signal by modulating a parameter of the signal. The receiver may decode the incoming signal according to the information code, to recover a series of bits corresponding to the address and command. The receiver may initialize a bit sequence index when the first bit is decoded. The preamble code may be a DC-free code, and the receiver may take the average as a reference value for decoding the information. In an alternate arrangement, the information may be encoded according to plural DC-free codes, so that the plural codes are applied to successive bits in the message according to a predetermined overlay code. Decoding devices employing analog domain operations are also disclosed.</p> |
