Burr-brown Research Corporation

Wilfred W Olschewski

Robert M Stitt, Ii

This disclosure relates to a housing or enclosure for an electronic component such as a hybrid module to provide RF shielding therefor. The RF shield has a gap separating two parts of the housing or enclosure to provide D.C. isolation between input and output electrical grounds. In one embodiment, the gap is attained by positioning a split metal sheet or layer within dielectric material such as an inner and outer layer of plastic material. Thus, the gap between the split portions of the RF shield is fixed, set or positioned during the formation of the sandwich dielectric-metal-dielectric structure. The gap has a very narrow spacing to obtain optimum RF shielding while still providing D. C. isolation. The dielectric material in the gap between the two split metal portions of the RF shield prevents electrical arcing between the split portions. In another embodiment, a dielectric, gap forming and metal holding (and separating) member is used to separate the two metal portions of the RF shield.

RF Shield for an electronic component

This relates to a transformer coupled isolation amplifier employing multiple primary and secondary windings to separate power supply currents from signal currents. An input section includes an input amplifier, a flyback modulator and a first flyback demodulator. An output section includes an output amplifier and a second flyback demodulator. A power section alternately provides a voltage and a high impedance to the transformer, which voltage is coupled to the input and output amplifiers via first and second primary and first and second secondary windings respectively for the purpose of providing positive and negative power sources to the amplifiers. The input demodulator is coupled to the output demodulator by third primary and secondary windings.

Isolation amplifier

A semiconductor interface circuit and method of operation for transmitting and receiving information between a telephone set and a four wire switching system. The interface circuit includes DC current sources which may be modulated by a voice signal from the switching system. The current sources provide both DC power and the voice signal to the telephone set through a two wire cable. A high impedance amplifier amplifies the signal on the cable, which cable signal includes a DC voltage, a microphone signal from the telephone set, and a component due to the voice signal from the switching system, all three being dependent on the cable length. Cable termination resistors are optional. The signal from the switching system and the DC component of the output signal of the amplifier are multiplied by an inverting multiplier circuit. The output signal of the multiplier circuit is proportional to cable length and is utilized to cancel the amplifier output signal component which is related to the voice signal from the switching system. Thus, echo return is eliminated or minimized regardless of cable length. Differential optical coupling circuits are utilized to couple the signal from the switching system to the cable and to couple the cable signal to the switching system relatively independently of the efficiency of the light emitting diodes of the differential optical coupling circuits. A DC ring insertion signal is coupled from the switching system to an output of the interface circuit via one of the differential optical coupling circuits. Status signals from the telephone set are conducted via another of the differential optical coupling circuits. The semiconductor interface circuit is housed in a package having two optically isolated cavities therein.

Interface circuit and method for telephone extension lines

An optical coupling system is described incorporating a light emitting semiconductive device mounted on a substrate having an electrically conductive strip leading to and from the device. A plurality of photo detector, semiconductive devices are mounted on the substrate adjacent to and co-planar with the light emitting device. A housing is mounted over the semiconductive devices and is filled with a clear light transmitting resin; the interior surfaces of the housing are light reflecting so that light emitted by the light emitting semiconductive device is reflected and diffused therefrom impinging upon each of the photo detector, semiconductive devices.

Optical coupling system

A ceramic substrate is provided with a plurality of planar conductors formed on a surface of the substrate; conductors extend substantially radially from an imaginary point on the surface of the substrate. A layer of dielectric material is formed over the major portion of each of the conductors to form a ring of dielectric material to which a ferrite toroidal core is adhesively secured. The core is precoated with an insulating material prior to adhesively being secured to the dielectric ring. A plurality of wire conductors are wire bonded at each end thereof to the exposed ends of the metal conductors on the substrate.

Growing community of inventors

Tucson, AZ, United States of America

Wilfred W Olschewski