| 摘要 |
#CMT# #/CMT# The device has a flat dish (20) mounted in a case (10) and electronically connected to an outer coaxial cable (30) which is adapted for being connected to a digital television. A coaxial cable connector (11) mounted across the case projects within and outside of the case and is connected to the cable. A coaxial transmission line (23) is mounted within the case and is connected between a feed point (21) of the dish and the cable. The line has a fixed capacitance irrespective of the distance between the feed point and the connector. #CMT#USE : #/CMT# Used for a portable digital television to receive digital program signals so that the television displays video and plays sound. #CMT#ADVANTAGE : #/CMT# The coaxial transmission line has fixed capacitance irrespective of the distance between the feed point of the flat dish and the coaxial cable connector so that the impedance of the flat dish is adapted to an antenna signal processing circuit, thus permitting the antenna devices of different sizes to utilize the same signal processing circuit, and hence reducing the fabrication cost of the antenna devices. #CMT#DESCRIPTION OF DRAWINGS : #/CMT# The drawing shows a perspective view of a digital receiving antenna device. 10 : Case 11 : Coaxial cable connector 20 : Flat dish 21 : Feed point 22 : Earthing point 23 : Coaxial transmission line 30 : Outer coaxial cable 111 : Inner conductor 112 : Outer conductors 231 : Core conductor 232 : Braided layer. |
