Abstract: A short range magnetically coupled wireless communication system employs time variant modulation of a high repetition rate pulse stream and magnetic coupling between a transmission magnetic element and a receiving magnetic element. The pulse stream is modulated by an input audio frequency signal in the time domain, for example, through pulse position modulation, pulse width modulation or pulse symmetry modulation. The receiving magnetic element is coupled to a demodulator circuit which detects the transmitted pulses induced in the receiving magnetic element and reproduces the audio frequency signal. Transmission over short range is thus efficiently accomplished through magnetic coupling in a simple, low cost, low power consumption communication system.

Abstract: A short range magnetically coupled wireless communication system employs time variant modulation of a high repetition rate pulse stream and magnetic coupling between a transmission magnetic element and a receiving magnetic element. The pulse stream is modulated by an input audio frequency signal in the time domain, for example, through pulse position modulation, pulse width modulation or pulse symmetry modulation. The receiving magnetic element is coupled to a demodulator circuit which detects the transmitted pulses induced in the receiving magnetic element and reproduces the audio frequency signal. Transmission over short range is thus efficiently accomplished through magnetic coupling in a simple, low cost, low power consumption communication system.

Abstract: A pulse driver circuit for providing very high frequency pulses with fast rise time to neon or gas discharge lamps to thereby produce higher optical output than is possible using conventional drivers. Gas discharge lamps have at least two states of operation. One is the application of breakover voltage to initiate gas ionization which may be called the preionization state. The second state is known as the breakdown condition which is when the gas in the lamp has ionized and is producing the optical output. The pulse driver, starts the ionization at a relatively low breakover voltage because of its fast rise time. The pulse driver comprises an astable oscillator, the output of which passes through a pulse width capacitor. The generated pulse train drives a power driver transistor which causes current to flow through a transformer causing a voltage to be applied to a lamp.

Abstract: Apparatus for multiplexing or demultiplexing multiple laser beams of different wavelength. In multiplexing, the outputs from multiple diode lasers are combined in such a manner as to produce a practically parallel set of beams for direction onto a diffraction grating. The latter component deflects each beam from its normal path by an angular amount determined from the wavelength of the incident light. The angles of incidence of the multiple beams are chosen to provide angles of diffraction that are practically identical for all wavelengths under consideration. In demultiplexing, similar apparatus includes a diffraction grating to provide angular dispersion of the multiple wavelengths, at least one lens to magnify the angular differences, and a set of detectors positioned in the paths of the dispersed beams of different wavelengths.

Abstract: An optical temperature gauge using a semiconductor crystal (12) having a band-edge shift property which is temperature dependent. An external narrow band light source (10) provides optical excitation through an optical fiber (11) and light energy thus passed through the crystal (12) is conveyed by a second optical fiber (13) to a light-to-electric transducer (14) at an external location, the crystal (12) thereby being locatable in cryogenic or other systems, to provide remote read-out. The light wavelength is varied (scanned) in a repetitive pattern in source (10), the instantaneous wavelength passing over the band-edge wavelength during each cycle of the scan. The timing of the crossover is related to the temperature of the crystal by electronic means (15 and 17). Several alternative elements of instrumentation are disclosed.