Abstract: A transmit/receive radio set having a transmitter output stage, a receiver input stage, and an antenna switching device for change-over between transmission and reception by a single antenna. Two impedance transformers are provided at the output of the transmitter output stage. A switching circuit effects a change-over of the output impedance of the transmitter output stage during transmission and reception by controlling the impedance of at least one of the impedance transformers.

Abstract: A phase shifter VCO has at least first and last fundamental circuits each including an amplifier adding circuit, a control input connected to all of the other control inputs for a tuning potential varying an amplification operative ratio between the first input and the output to the second input and the output of the adding circuit, a reference input for a reference potential, symmetrical first and second non-inverting and inverting circuit input pairs, a symmetrical non-inverting and inverting circuit output pair, and a symmetrical timing element having an input connected to the first circuit input and having an output forming the first input of the adding circuit. The first non-inverting input of the first fundamental circuit is connected to the non-inverting output of the last fundamental circuit, and the first inverting input of the first fundamental circuit is connected to the inverting output of the last fundamental circuit.