Bidirectional amplifier

A bidirectional amplifier, comprising,

• first and second ports;
• circuitry connected between said first and second ports, said circuitry arranged to:
• in a first mode, amplify a signal applied at said first port and provide said amplified signal at said second port;
• and to:
• in a second mode, amplify a signal applied at said second port and provide said amplified signal at said first port.

A bidirectional amplifier, comprising:

• first and second ports;
• first and second nodes coupled to said first and second ports, respectively;
• first and second ac-coupling capacitors connected between said first and second nodes and third and fourth nodes, respectively;
• first and second transistors connected in a first common emitter cascode arrangement between said third node and a fifth node;
• third and fourth transistors connected in a second common emitter cascode arrangement between said fourth node and said fifth node;
• a fifth transistor connected between said fifth node and said first node;
• a sixth transistor connected between said fifth node and said second node;
• a first current source which conducts a current Ibias1 connected between said first node and a circuit common point;
• a second current source which conducts a current Ibias2 connected between said second node and said circuit common point;
• and
• first and second bias points coupled to said third and fourth nodes, respectively;
• said bidirectional amplifier arranged such that:
• in said first mode, said first and second bias points are arranged to enable said first common emitter cascode arrangement and disable said second common emitter cascode arrangement, said sixth transistor operates as an emitter follower and forms a gain stage with said first common emitter cascode arrangement and said fifth transistor operates as a feedback emitter follower, such that said bidirectional amplifier amplifies a signal applied to said first port and provides said amplified signal at said second port;
• and such that:
• in said second mode, said first and second bias points are arranged to enable said second common emitter cascode arrangement and disable said first common emitter cascode arrangement, said fifth transistor operates as an emitter follower and forms a gain stage with said second common emitter cascode arrangement and said sixth transistor operates as a feedback emitter follower, such that said bidirectional amplifier amplifies a signal applied to said second port and provides said amplified signal at said first port.