TRANSCEIVER_T_R_SWITCH

Published:2009/6/24 3:17:00 Author:Jessie | From:SeekIC

This transceiver's transmit/receive switch uses PIN-diode instead of a relay. On receive, D1 is cut off, D2 is cut off and the antenna connects to the receiver. During transmit, D1 is forward-biased, as is D2. This connects the receiver input. This causes the input impedance of the transmission line to be high, so little transmitter power reaches the receiver. Although not shown in the schematic, the 12-V supply should have a series resistor of 100Ω to 2.2kΩ, depending on diode current, to limit diode current to a safe value.



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