Hughes Aircraft Company

Hughes Electronics Corporation

Wilbert B Copeland

Arnold L Berman

Robert A Brunner

Russ A Reisner

Shih-Chang Wu

Charles C Curello

Keith Williams

William L Ballhaus

Samuel A Milliken

Erik Soderburg

John Dunwoody

An analog transponder processor for use in a multibeam satellite receiving input beam signals and transmitting output beam signals has an input switch matrix, channel processors, and an output switch matrix. The input switch matrix power divides input beam signals into sets of input beam signals. The channel processors each receive at least one input beam signal from the input switch matrix. The channel processors filter the input beam signals into channel signals. Each of the channel signals corresponds to a respective channel of the input beam signals. The channel processors change the frequency of at least one channel signal such that the at least one channel signal corresponds to a different channel than the respective channel of the input beam signals. The output switch matrix combines the channel signals into output beam signals.

Reconfigurable analog channel processor for multibeam satellites

Transponder systems are disclosed for routing signals from a plurality of input frequency channels at each of a plurality of receive antennas to a plurality of output frequency channels at each of a plurality of transmit antennas. The routing is preferably processed at an intermediate frequency. A plurality of bandpass filters are coupled to each receive antenna to define input signal paths. First and second mixers are positioned in series with each bandpass filter. A mixing signal at the first mixer adjusts the frequency of a selected one of the input signals to pass it through the bandpass filter and onto the respective input signal path. A mixing signal on the second mixer translates the frequency of that input signal to have a frequency order in the intermediate frequency band that corresponds with the frequency order of a selected one of the output frequency channels at its respective transmit antenna. Each of the transmit antennas is coupled to a common signal path of an adder. The adder has a plurality of intermediate signal paths which are each connected through a plurality of switches to a selected one of the input signal paths.

Interconnective transponder systems and methods

Input RF signals to a transponder, such as a communications satellite, are down converted to a lower intermediate frequency (IF) that is common for each different channel. The channel signals are all processed at the common IF, and then up converted to different respective transmission frequencies. This allows for a down conversion/signal processing/up conversion unit design that is the same for each channel (except for frequency and gain values), and facilitates the use of inexpensive available standard components as well as low bandwidth channel filters. An improved phase noise cancellation phase lock loop (PLL) is preferably used to generate tuning signals used in the up and down conversion processes. The PLL includes two loop mixers, with the down and up conversion mixing signals taken respectively from the inputs to the first and second loop mixers. The first and second loop mixers receive mixing signals at frequencies (T-R) and (T-IF-N.multidot.CLK) respectively, where T is the channel's transmission frequency, R is its reception frequency, N is the PLL's .div.N factor, and CLK is a clock frequency; the PLL's voltage controlled oscillator provides the down conversion tuning signal and the input to the first loop mixer at a frequency (R-IF), while a (T-IF) tuning signal for the up converter is taken from a filtered output of the first loop mixer.

Multi-channel transponder with channel amplification at a common lower

A linearizer particularly valuable for millimeter wave satellite communications is disclosed. A satellite (12) divides signal into linear (20) and nonlinear (32) paths which are converted to finline. A pair of beamlead PIN diodes (48) and a pair of varactor diodes (52) extend across the finline linear path to constitute an attenuator and phase shifter. A pair of anti-parallel Schottky diodes (60) and a pair of PIN diodes (64) extend across the nonlinear path to constitute a limiter and an attenuator. A combiner (30) combines the linear and nonlinear signals for input to an amplifier.

High frequency linearizer

A predistortion linearizer (20) is operative with a microwave signal, as may be provided by signal source (62) to linearize the gain of a power amplifier, such as a traveling-wave-tube power amplifier (74), by introduction of an amplitude and/or a phase distortion to the microwave signal wherein the distortion is inverse to a distortion introduced by the power amplifier, thereby to compensate for the distortion of the power amplifier. The linearizer is constructed of two channels (22, 24) which are operated in parallel but approximately 180 degrees out of phase, with an additional phase increment provided by delay lines (46, 56) to offset one channel from the other channel by a phase difference in a range of approximately 160-200 degrees. Included within each channel is a diode circuit (40, 50) wherein the diode circuit (40) includes a set of PIN diodes operated in linear fashion in the channel (22), and the diode circuit (50) includes a set of Schottky diodes operated in nonlinear fashion in the channel (24). The limiter diode circuit (50) limits signal amplitude resulting in a gain expansion and a phase advance upon summation of signal vectors of the two channels to provide an output signal. These are adjusted to compensate for the gain compression and phase lag of the power amplifier. In each of the diode circuits, the diodes are mounted on components of a coplanar waveguide for symmetry in construction and avoidance of generation of parasitic reactances.

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Los Angeles, CA, United States of America

Wilbert B Copeland