| 摘要 |
<p>A circuit for selecting an input to a signal processing network from among several switchable antenna units. Each antenna unit (26) includes a winding (30) which is connected to a common signal bus. The switchable antenna units (12) may be placed in "on" or "off" states in response to a controller, such as a microprocessor (46). One terminal (36,40) of each winding (30,32) is connected to a transistor (42,48) which causes the terminal to be in an open condition when the unit is unselected, attenuating any signal which might otherwise be transmitted to the signal bus. A second winding (32) is inductively coupled to the first winding (32) and is used to improve attenuation of unselected signals.</p> |
