Impedance matching using active couplers

摘要

Circuitry (100) for providing impedance compensation between a source impedance (501) and a load impedance (505) which is proportional to the source impedance comprises: a pair of directional couplers (200 and 300), each coupler including bidirectional transmitting and receiving paths and a unidirectional path coupling these paths; means (121) for cascading the transmit path of one coupler to the receive path of the other; and unidirectional amplifier (400) for interconnecting the remaining bidirectional transmission ports. The impedance match to the source is obtained by adjusting the amplifier gain in correspondence to the number of essentially identical terminations that are bridged to form the load impedance. Means (510-515) sense the number of active terminations and transmit this information to the amplifier so the appropriate gain setting may be established.