| 摘要 |
An antenna alignment meter comprises a signal detector circuit 1 for detecting a signal with certain characteristics, e.g. frequency, polarisation, or error or data rate, a connector for connecting the detector circuit to the antenna 4, and a indicator 11 for indicating that a signal with the required characteristics has been received by the antenna. Preferably the apparatus is hand held and user operated 14 by adjusting the antenna orientation until the received signal has either maximum strength, optimum quality or horizontal and vertical polarization components with equal strength, and then the antenna is locked into position. Preferably the meter has a memory 12 which stores data concerning the required signal characteristics which may be loaded into the memory via a communications port 13. The meter may also have a signal amplifier with automatic gain control and a display for displaying information about received signal, e.g. the signal strength. The meter's power supply 15 may have an automatic switch off facility which places the meter into standby mode after a preset time. When the received signals are encoded television signals the meter may be provided with a decoder 10 so that the signals may be displayed. |
