Telecommunications – Receiver or analog modulated signal frequency converter – With wave collector
Patent
1996-06-12
1998-11-10
Eisenzopf, Reinhard J.
Telecommunications
Receiver or analog modulated signal frequency converter
With wave collector
455133, H04B 106, H04B 1702
Patent
active
058358552
ABSTRACT:
An antenna system for a communication device which receives and/or transmits packets of data having a characteristic reception interval comprises first and second antennas which are spatially diverse. A feed circuit is coupled to the first and second antennas to connect the first and second antennas to the communication device. The feed circuit includes a switching circuit and an oscillating switch driver which periodically select the first antenna and the second antenna, with a period which is normally substantially greater than the characteristic reception interval for the communication system. For example, if the period of the switching circuit is about one hundred milliseconds, and the data packet length is only 1.22 milliseconds as in the case of Ethernet, then many packets can be transmitted during each antenna configuration state. If both states are such that neither antenna is in a multipath null then no packets are dropped. If one antenna position is in a null, then the probability of the other position being in a null is vanishingly small. With a period of about 100 milliseconds, if one position is in a null there will be an interruption in the link. However, the user will not perceive the delay due to the fact that one tenth of a second is very short in terms of human reaction times. Another important point is that the switching on and off of each antenna is done relatively gradually. This is done so that the receiving station sees no switching impulses and so that the antenna environment changes gradually with respect to packet length.
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3Com Corporation
Bhattacharya Sam
Eisenzopf Reinhard J.
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