Teledynamic Control by Selective Ionization with Application to Radio Receivers

This paper concerns a new and improved method of remote control which may be applied to electrical devices of any sort. Special attention is given to the exposition of the basic principles of the system as applied to the remote control of radio receivers. The new control arrangement utilizes the alternating-current power line as a medium for transmission of control signals from a remote unit to the controlled device, and is therefore free of the limitations imposed by control cables. The system utilizes a small oscillator, located at the remote point, operating at a frequency between 200 and 400 kilocycles. Use of the 60-cycle line voltage as plate supply causes the radio-frequency output voltage of the remote unit to be modulated in intensity. Control signals are transmitted through the alternating-current power line to the controlled point, where the phase of the 60-cycle line voltage is compared with the phase of the envelope of the radio-frequency control signals in any one of several phase detectors which may be employed for selective purposes. Relays in the detector output circuits are energized and may be made to close power circuits to any desired electrical device. Remote control of the start of operation of an electric appliance may be had without the expenditure of stand-by power in receptive circuits at the controlled point.