Abstract: A method and apparatus for providing an antenna condition signal and a feeder cable condition signal in a base station having an antenna coupled to a cabinet by an antenna feeder cable. Two directional couplers are configured to detect forward and reflected signals to and from the antenna. Power detectors are coupled to the RF couplers, and are configured to provide forward and reflected power signals. A first differential amplifier provides a detector tuning signal proportional to the difference between the forward and reflected power signals. A second differential amplifier provides a detector tuning signal proportional to the difference between the forward and a reference voltage. Each differential amplifier tunes a voltage controlled oscillator (VCO). The output of the VCOs is coupled to the feeder cable. A phase locked loop at the cabinet is coupled to the feeder cable and provides a recovery tuning signal which tracks the tuning signals to the differential amplifiers.
Abstract: A circuit for an output divider has an input port, an output port coupled to the input port at a first node, and a voltage controlled element, such as a varactor, having a first end coupled at the first node to the input port. A second end is coupled to a resistive element, such as a resistor, with the resistive element being coupled to a signal ground. The first end of the voltage controlled element is adapted to be coupled to a reference voltage of a load, the voltage controlled element having a high impedance when the reference voltage is present and having a low impedance when the reference voltage is not present. The impedance seen from the input port is substantially the impedance of the load when the reference voltage is present, and the impedance seen from the input port is substantially the impedance of the resistive element when the reference voltage is not present.
Abstract: Apparatus and an associated method for improving the receiver portion of a radio receiver, such as the receiver portion of a radio base station operable in a cellular communication system. A mast head amplifier is provided at a mast head to amplify electrical signals formed by the mast head. The amplification level of the mast head amplifier is selected to be relatively large to more than overcome the loss and sensitivity degradation of the amplified signal when conducted therethrough to other portions of the receiver. An attenuator which exhibits a selected level of attenuation is positioned in-line between the feeder cable and the remaining portions of the receiver. The attenuation level is selected to provide a constant level of gain in a signal provided to the remaining portions of the receiver.