Abstract: A multi-phase coupler including a noise reduction circuit which provides two output signals which are separately shifted in phase with respect to an input radio frequency (RF) signal. The input RF signal is capacitively phase-shifted to lead the phase of an input RF signal to provide one output signal and is inductively phase-shifted to lag the phase of an input RF signal to provide a second output signal. The two phase-shifted outputs are impedance matched to the dual input ports of a balanced radiating structure that acts as a point source when the input ports are driven in phase quadrature.

Abstract: A power supply which automatically produces approximately the same output voltage from two or more input voltages where the input voltages have substantially different magnitudes.

Abstract: A terminal unit having a digital autostart circuit for energizing an output device such as a teleprinter. The autostart circuit responds only to the space character which is transmitted between every word in the commonly used Murray and ASCII codes. A method for detecting the presence of information signals encoded in the Murray and ASCII codes wherein a predetermined bit of each incoming signal is inverted and the binary states of each bit of incoming character are sensed to determine the presence of the space character.

Abstract: An indicator for displaying RTTY signals in a terminal unit. The terminal unit converts mark and space signals from a radio receiver at audio frequencies to digital pulses for a readout device. Proper tuning of the radio receiver is facilitated by viewing the displayed signals. The readout device converts the digital pulses to alphanumeric characters.

Abstract: A converter for converting radio teleprinter audio frequency signals from a radio receiver into teleprinter signals which are bipolar pulses for operating an output device. The converter includes a binary pulse decoder, which may be used independently in other applications, and a pair of substantially identical demodulator channels.In radio teleprinter applications the novel decoder is coupled to two substantially identical demodulator chanels which demodulate pulses from incoming information signals at audio frequencies. In the demodulator channels the frequencies of the information signals, which commonly are received by the demodulator channels on different audio frequencies, are shifted to the same audio frequency by mixing them with a signal from a respective local oscillator in each demodulator channel. The demodulator channels each detect a series of DC pulses from the audio signals and apply the DC pulses to the decoder.