| 摘要 |
A diversity receiver switches between at least two antennae (12) when the noise level of a processed receiver signal (26) exceeds a predetermined level. A diversity circuit (24) extracts the noise from the receiver signal (26) with a bandpass filter (50) and compares the level of the noise to the predetermined level. When the noise exceeds the predetermined level, the diversity circuit (24) sends a command signal (22) to switching circuitry (14) to switch from the antenna (12) currently responsible for the receiver signal (26) to another antenna (12). If the noise in the receiver signal (26) indicative of the signal (18) received by the now-coupled antenna (12) still exceeds the predetermined level, then the switching circuitry (14) continues to switch between antennae (12) until an acceptable noise level is achieved. A sync separator circuit (172) may be provided if antenna switching is desired during the vertical or horizontal blanking intervals. A plurality of antenna/receiver-circuit (210, 212) combinations may also be employed with the switching circuitry (280) to switch between the receiver circuit (210) with a dedicated antenna (212) rather than between the antennae (212) themselves.
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