Abstract: An antenna feed horn assembly includes a circular feed horn having an electrically conductive wall with an edge defining a circular aperture. The antenna feed horn assembly further includes a circular waveguide mounted to the base of the circular feed horn and including an endplate. An cylindrical rod extends from the center of the endplate towards the center of the feed horn aperture along a longitudinal axis of the antenna feed horn assembly to minimize undesired reflections produced by transitions between electrically conductive material and non-electrically conductive material or dielectric within the antenna feed horn assembly. An antenna feed horn assembly can also include a splash plate opposite the endplate, the center from which another cylindrical rod extends towards the center of the endplate along the longitudinal axis of the antenna feed horn assembly to further minimize undesired reflections.

Abstract: A CMOS Class F amplifier uses a differential input to eliminate even-order harmonics, thereby avoiding the need for circuits that are tuned to the second harmonic. This also minimizes the sensitivity of the design to changes in the second harmonic frequency and/or the particular component values selected for the tuned circuit. Third-order harmonics are reduced by controlling the phase relationship between the differential inputs. Additional efficiency is achieved by dynamically controlling the impedance of the amplifier as a function of output power level.

Abstract: A C-Band or Ku-Band satellite communication system uses a relatively small receiving antenna while operating within current FCC designated bandwidth and using existing satellite configurations. Aperture synthesis techniques create nulls in orbit locations from which potential interference is expected. Bandwidth inefficient modulation techniques reduce transmission power flux density. Video compression reduces the power necessary to transmit video information. These three features make possible a receiving antenna with a receiving area equivalent to that of a three foot diameter dish, at C-Band frequencies. Comparable reductions are possible for Ku-, Ka-, S- and L-Band systems. Compressing the data reduces the required transmitted power by a factor of ten. Spreading the bandwidth reduces the power density below the FCC limitation.

Abstract: A receiving antenna includes a parabolic reflector and a feed horn. The feed horn includes an electrically conductive wall with an edge forming an aperture. The feed horn further includes a plurality of electrical conductors that extend from the edge to the center of the feed horn in a substantially coplanar relationship with the aperture. Each of the electrical conductors differentially affect a first polarized electrical field perpendicular to the edge adjacent the electrical conductor and a second polarized electrical field parallel to the edge adjacent the electrical conductor. In this manner, the electrical conductors can be configured to reduce the effective aperture of the feed horn in a plane, so that a first polarized horn radiation pattern produced by the feed horn can be circularized.

Abstract: A C-Band or Ku-Band satellite communication system uses a relatively small receiving antenna while operating within current FCC designated bandwidth and using existing satellite configurations. Aperture synthesis techniques create nulls in orbit locations from which potential interference is expected. Bandwidth inefficient modulation techniques reduce transmission power flux density. Video compression reduces the power necessary to transmit video information. These three features make possible a receiving antenna with a receiving area equivalent to that of a three foot diameter dish, at C-Band frequencies. Comparable reductions are possible for Ku-, Ka-, Sand L-Band systems. Compressing the data reduces the required transmitted power by a factor of ten. Spreading the bandwidth reduces the power density below the FCC limitation.

Abstract: A C-Band or Ku-Band satellite communication system uses a relatively small receiving antenna while operating within current FCC designated bandwidth and using existing satellite configurations. Aperture synthesis techniques create nulls in orbit locations from which potential interference is expected. Bandwidth inefficient modulation techniques reduce transmission power flux density. Video compression reduces the power necessary to transmit video information. These three features make possible a receiving antenna with a receiving area equivalent to that of a three foot diameter dish, at C-Band frequencies. Comparable reductions are possible for Ku-, Ka-, S- and L-Band systems. Compressing the data reduces the required transmitted power by a factor of ten. Spreading the bandwidth reduces the power density below the FCC limitation.

Abstract: A C-Band or Ku-Band satellite communication system uses a relatively small receiving antenna while operating within current FCC designated bandwidth and using existing satellite configurations. Aperture synthesis techniques create nulls in orbit locations from which potential interference is expected. Bandwidth inefficient modulation techniques reduce transmission power flux density. Video compression reduces the power necessary to transmit video information. These three features make possible a receiving antenna with a receiving area equivalent to that of a three foot diameter dish, at C-Band frequencies. Comparable reductions are possible for Ku-, Ka-, S- and L-Band systems. Compressing the data reduces the required transmitted power by a factor of ten. Spreading the bandwidth reduces the power density below the FCC limitation.

Abstract: A data transmitting/receiving satellite terminal for transmitting to and receiving from a geosynchronous satellite employs an antenna having nulls in its antenna receiving pattern at a first frequency corresponding to satellites spaced at regular intervals from the satellite. In addition, a phase and amplitude compensation network adjusts a phase and amplitude of the transmitted signal to compensate for transmitting at a different frequency than for which the antenna is optimally designed. The antenna includes a main parabolic reflector, and two side parabolic reflectors offset from a plane parallel to the main parabolic reflector. Each of the reflectors uses a dual frequency feed horn to couple energy to and from the reflector to a dipole exciter to which the receiving electronics is coupled. The above terminal is particularly useful in C-Band applications.

Abstract: An adapter for a direct broadcast television system enables owners of existing dish antennas to receive both current analog television broadcasts and new digital television broadcasts via C-Band satellites. The adapter includes a coaxial switch for switching between analog and digital television, a tuneable demodulator for selectively switching between transponders on the C-Band satellites, a channel selector unit for selecting the channel specified by the user from the bit stream output by the demodulator, a channel expander for decompressing the video signal, and a control unit for accepting user commands and controlling the polarization of the received signals, the steering of the TVRO antenna, the demodulated transponder frequency and the demultiplexed channel. The ability to select the user's channel from multiple channels available on different transponders and different satellites allows the dynamic reassignment of television channels based on system efficiency considerations.

Abstract: An RF communications receiver permits greater integration on standard silicon chips and consumes less power than previous receivers. Sub-sampling and discrete-time signal processing techniques are used to frequency down-convert, filter, amplify, and select a desired analog RF channel. A sample-and-hold circuit sub-samples the desired analog RF channel of carrier frequency f.sub.c, thereby down-converting it to a discrete-time image signal of frequency f.sub.i. Successive down-sampling, anti-alias filtering, and amplification of the discrete-time image signal yield a low-frequency discrete-time signal containing a down-converted channel of frequency f.sub.k. The low-frequency discrete-time signal is then digitized, filtered, and demodulated to reveal its baseband information content.

Abstract: A digital solid state electric power usage meter for determining power usage by a load attached to an electric power network. The meter has a current sensor coupled to each phase of the electric power network for sensing current in each phase, a voltage divider coupled to each phase of the power network for detecting the voltage level on each phase, an analog to digital (A/D) converter coupled to the current sensors and voltage dividers receiving signals from the current sensors related to the current in each phase and signals from the voltage dividers related to the voltage on each phase.

Abstract: A digital solid state electric power usage meter for determining power usage by a load attached to an electric power network. The meter has a current sensor coupled to each phase of the electric power network for sensing current in each phase, a voltage divider coupled to each phase of the power network for detecting the voltage level on each phase, an analog to digital (A/D) converter coupled to the current sensors and voltage dividers receiving signals from the current sensors related to the current in each phase and signals from the voltage dividers related to the voltage on each phase.

Abstract: An electrical transmission line has improved signal transmission characteristics, low attenuation, constant phase and group velocity and constant and nearly ohmic characteristic impedance over a wide frequency band by providing low magnetic loss inductance along with the shunt capacitance of the insulation surrounding the conductors. The low loss inductance can be provided by particulate magnetic material, such as ferrites, homogeneously distributed in the insulating material or alternatively the inductance can be provided by ring(s) of magnetic material concentric with the conductor or by layer(s) of magnetic material when the conductor(s) are flat. A variety of radial or longitudinal profiles of the doping level is possible and can be used in combination with any of these basic loading designs. These concepts can be applied in twisted pair, coaxial or high voltage power transmission and distribution single or three phase cables or strip lines and other breadboard applications.

Abstract: An analog function generator useful in providing a variety of functions for analog signal processing applications includes a pulse width modulator and a switched capacitor operational amplifier. Capacitors in the input of the operational amplifier and in the feedback loop of the operational amplifier are selectively switched by the output of the modulator to create output voltages of the amplifier that are polynomial, logarithmic or exponential functions of the input voltages to the amplifier and pulse width modulator.

Abstract: A tone generator is disclosed comprising an LSI controller and read only memory to provide any one of a pre-established set of audio signals to a standard pulse code modulated data stream. This is accomplished utilizing the origination address and destination address that appear on the origination and destination buses in every cycle of data. The origination address designates any one of the pre-established signal patterns stored in the ROM. The designated signal is read onto the data bus by the disclosed signal generating system by reading out the elements of the signal tone stored in the ROM. The predefined tones are stored continuously and regenerated continuously by the controller; thus, each tone is available during each frame cycle to be read out when the origination address calls for the tone. The samples of the tones and signals are stored in the ROM in the digital form they will have on the PCM data bus.

Abstract: A telephone line interface which performs the BORSHT functions employs pulse width modulation and eliminates dc in the transformer to reduce the size of the coupling transformer thereby reducing space and costs. The ring function is provided to the subscriber without use of mechanical relays. An automatic, dynamically adjusted hybrid network is provided for removing echo signals thereby providing major improvement in two-to-four wire conversion performance. The circuitry lends itself to large scale integration thereby reducing space and cost and improving reliability.