A radio transceiver amplifier with closed loop gain control feedback for a trunked mode and open loop bias feedback for a direct mode

A remote radio for a radio system is described. The remote radio includes transmitting means (12), receiving means (11) and control means 13 coupled to the transmitting means and the receiving means for control thereof, the control means being arranged to control the radio in first and second modes, where, in the first mode, the receiving means is controlled to receive channel control commands from a base station and in the second mode the transmitting means and receiving means are controlled for direct communication with another remote radio (30). The transmitting means includes a power amplifier 50 measuring means 70 for measuring the output from the power amplifier, first 60 and second 80, 81, 85, 86, 87, 89, 52, 51 feedback means for controlling the power amplifier in response to the measuring means, and switching means 74 for selectively switching between the first and second feedback means. The first feedback means 60 is arranged for closed-loop adjustment of the power amplifier, and the second feedback means is arranged for open-loop adjustment of the power amplifier. The switching means 74 is controlled by the control means 13 to select the first feedback means for operation in the first mode and the second feedback means for operation in the second mode. The arrangement is particularly suitable for use in a radio system where the radio is arranged to operate in a first mode under the control of the base station (e.g. trunked mode) and a second, direct radio-to-radio, mode of operation.