Terminal equipments for short-wave point-to-point radio links

In order to secure satisfactory operation from a radio link it is necessary to supply at the ends of the link terminal equipment which shall not only provide the necessary circuit arrangements, but shall also provide means for controlling its technical performance. In the present paper the arrangements necessary for speech transmission are dealt with in detail, and a brief description is given of the facilities for technical operation and control of the circuit. The various sections are concerned with (1) anti-singing and echo-suppressing devices, (2) amplifier detectors and delay networks, (3) gain control, (4) circuit arrangements, (5) voice-operated relay circuits, (6) switching of privacy equipment, (7) monitoring and control, (8) equipment.