| 摘要 |
The portable receiver is carried by a car driver to enable operation of the anti-theft system. It comprises two antennae (10,20) orientated along different axes, each connected to a phase-shifting circuits (12,22). A multiplexing circuit (24) combines the outputs of the two phase-shifting circuits. This provides a constant amplitude output regardless of receiver orientation. The portable receiver comprises two antennae (10,20) which are designed to receive electromagnetic signals and are orientated along different axes. The receiver also includes two phase-shifting circuits (12,22), each connected to an antenna, and a multiplexing circuit (24) combining the outputs of the two phase-shifting circuits. Between at least one of the phase-shifting circuits and the corresponding antenna there is a correcting circuit (Rcor). This co-operates with the phase-shifting and multiplexing circuits to supply two outputs from the two phase-shifting circuits which are shifted by an angle pi/2 relative to each other, substantially equal in amplitude. |
