Hughes Electronics Corporation

Hughes Aircraft Company

The Boeing Company

Hughes Electrical Corporation

Arnold L Berman

Michael I Mandell

Marvin R Wachs

Wei-Chun Wang

Harold A Rosen

James D Thompson

David L Crampton

Tong-Jyh Lee

Steven O Lane

Robert E Vaughan

Chak M Chie

Carl J Hahn, Iii

Wilbert B Copeland

John R Grebliunas

Charles C Curello

Todd K Citron

Howard T Ozaki

Victor S Reinhardt

William W Mayfield

Robert A Brunner

Russ A Reisner

Mark D Heal

Joseph E Davis

I Mark Shahriary

William L Ballhaus

Samuel A Milliken

Gilles G Du Bellay

A design tool and method characterizes a circuit at a hardware level description. A behavioral level description of the circuit is created. Symbolic equations for components of the behavioral level description are created. The behavioral level description is partitioned by inserting a marker component into the behavioral level description of the circuit to simplify subsequent processing used to prove equivalence between the behavioral and hardware level descriptions. The symbolic equations are back-substituted until output variables are expressed in terms of input variables that determine the output variables. The marker component is defined using a unique symbolic name. Current time counts of each clock cycle are used to compute an index for the marker component. The behavioral level description is transformed to produce symbolic and numeric files for compilation to gates and proof of functionality.

Marker argumentation for an integrated circuit design tool and file structure

An improved method is provided for seamlessly combining adjacent subchannels in a signal processing system. Each adjacent subchannel is defined to include a first and a second linear phase digital filter, where the filters are implemented using digital circuitry having a plurality of registers. Prior to summing the two adjacent channels, a delay is introduced into one of the two filters in each of the subchannels, such that the delay is equal to the delay associated with one register in the digital circuitry. The two adjacent subchannels are then combined to form a composite channel that exhibits linear phase.

Method for seamlessly combining adjacent filters in a frequency channelizer

A system and method for adjusting satellite communication signal transmit power for signals transmitted to a localized region within a satellite coverage area utilize real-time information on weather conditions ( ) and/or actual path losses ( ) within the localized regions to adjust the effective isotropic radiated power (EIRP) of the satellite beams ( ) to minimize the total radio frequency (RF) power required for transmission. The transmission system may be realized using a variety of antenna types for transmitting spot beams and/or area coverage beams. Representative antenna implementations include multi-beam antennas having a low-level beamforming network and hybrid matrix amplifier system, phased-array with independent input amplitude control and beamsteering for each beam, and a phased-array feeding a confocal imaging system for single broadcast beam per polarization. The present invention allows for the reduction of RF transmit power to achieve the same communications performance enabling either increases in satellite functionality and/or an increase in total capacity of the satellite communication system.

Satellite transmission system with adaptive transmission loss compensation

A design tool and method for characterizing a circuit at a hardware level includes the steps of generating a behavioral level description of the circuit and generating a netlist from the behavioral level description. Reference equations are generated from the netlist and are translated into numeric and symbolic C-code. The symbolic C-code is compared to the numeric C-code for validation. The reference equations are translated into numeric and symbolic HDL-code. The symbolic HDL-code is compared to the numeric HDL-code for validation. The symbolic C-code is compiled and simulated. A C-code equation file is generated. The symbolic HDL-code is compiled and simulated. A HDL-code equation file is generated. A symbolic manipulation program is used to solve for a difference between the C-code equation file and the HDL-code equation file. If there are no unexpected differences, equivalence is established.

Application specific integrated circuit design tool and file structure

A TDMA beacon for satellite system synchronization includes a beacon signal generator and a time division multiplexed switch. The beacon signal generator generates a beacon signal. The TDM switch is coupled to the beacon signal generator and receives the beacon signal. The TDM switch embeds the beacon signal with a data signal into a TDMA signal. The TDMA signal is then broadcast to a ground station where the beacon signal may be extracted from the TDMA signal and used to synchronize a terminal with the satellite system.

TDMA beacon for satellite system synchronization

A computer-implemented design tool architecture provides a mechanism for characterizing a circuit at a hardware level. The tool architecture has a medium for storing a description of an application specific integrated circuit (ASIC), where the description describes the ASIC at a behavioral level of a hierarchy. A library of foundry primitives map known ASIC components to code sets for a hardware description language (HDL). The tool architecture further includes a command interpreter for generating an electronic file based on a set of predefined computer-based commands such that the electronic file characterizes the circuit at the hardware level. The hardware level is at a lower level in the hierarchy than the behavioral level.

Architectural structure of a process netlist design tool

A unique transistor model and methods for analyzing the model are disclosed. The transistor model of the present invention is simple and requires specification of a minimal number of parameters to simulate transistor operation. Three analysis methods are disclosed, each having unique circumstances for application A first method is premised on sampling all waveforms in the circuit and determining the operating point of the transistor. The first method assumes an input of an arbitrary periodic waveform. The first method is very flexible and may be used with a wide range of models other than the disclosed model. A second and a third method are premised on input and output waveform clipping. The second method assumes a single tone input into the transistor. The third method is a combination of features from the first and second methods. The third method is computationally efficient and assumes an arbitrary periodic input waveform.

Transistor amplifier model and circuit analysis methods

A system and method for determining dispersion of intermodulation power in a satellite communication system or any other system which can be mathematically modeled as a matrix multiplication followed by an instantaneous nonlinearity and another matrix multiplication include determining a matrix (V) representing amplitudes and frequencies of signals generated by a digital processor and input to a plurality of amplifiers. A matrix (M) representing signal propagation from the amplifiers to a destination is used to determine the intermodulation power at the destination within each transmitted beam at each intermodulation distortion frequency. The intermodulation distortion frequencies are determined based on sums and differences of component frequencies corresponding to the user signals. By considering only third-order intermodulation effects and performing a frequency domain analysis, the present invention is computationally efficient enough to analyze cellular communications systems containing a large number of individual users, a large number of amplifiers, and a complex multi-beam antenna. The improvement of signal to intermodulation power ratio when going from the amplifiers on a satellite to the received signals on the ground.

System and method for analysis of intermodulation dispersion

A system and method for restricting access to a satellite repeater transponder (,) utilizes a pseudo-random noise generator (,) to automatically modulate a local oscillator (,) about a nominal frequency during frequency translation within the satellite transponder. The carrier signals of authorized user terminals (,) will be modulated with a matching or inverse noise waveform produced by a pseudo-random noise generator (,), so that the noise signal modulated onto the carrier signal will only be cancelled out in authorized transmissions. Thus, an unauthorized user terminal will be unable to recover the baseband signal due to insufficient carrier to noise ratio in the expanded bandwidth created by the pseudo-random frequency modulation in the satellite repeater.

Access control for multi-access satellite communication system

The new signal amplifiers dynamically adjust based on the signal's power level. When used on multi-beam satellites, increased signal power indicates an increase in traffic on the channel. The power level of the input signal is sensed and converted to a DC signal, which is applied to a control terminal of a power supply that regulates DC power supplied to the amplifier. During periods of increased traffic, an increase in system power is allocated to the channel. By monitoring traffic on a plurality of channels, available onboard power is allocated based upon the relative channel requirements. The sensed power of multiple channels is summed and scaled to determine the power requirement of the channel relative to the other channels. A command voltage received from a ground station may be switched in place of the summed voltage to allow amplification levels to be controlled from the ground station.

Dynamic power allocation system and method for multi-beam satellite

An algorithm (20) or method (20) for verifying that a system hierarchically built from smaller components implements a desired equation that represents the system. Symbolic data is clocked (24) through the system by processing a symbolic test vector using linked equations (22) written (21) for each component of the system. A resulting symbolic equation generated at the output of the system is recorded (25). The symbolic equation is then compared (26) with the desired equation for the system using a symbolic manipulation tool. If the comparison generates a zero difference, the system correctly implements the desired equation representative of the system, and vice-versa.

Architectural equation generating algorithm

An automatic and iterative simulation method for adjusting linearizer parameters to achieve desired AM/AM and AM/PM characteristics is disclosed. The disclosed method includes the steps of choosing a set of linearizer parameters, modeling the performance of the linearizer circuit and the power amplifier to calculate a performance index. The performance index is compared to a threshold. The method continues to iterate until the performance index is acceptable in comparison to the threshold. When the process is completed, the linearizer parameters are output for use by the designer. The disclosed method eliminates the need to engage in trial and error methods in a laboratory when combining a linearizer and a power amplifier to produce linear output characteristics.

Linearizer method and apparatus

The output impedance matching network of a power amplifier module is improved by the addition of an intermediate set of bonding pads in close proximity to a power transistor in the power amplifier module. A tunable set of bond wires extend from the intermediate bonding pads to a transmission line that is coupled to the output of the power amplifier module. The tunable bond wires allow the inductance of the impedance matching network to be tuned and optimized.

Tunable impedance matching network for a mic power amplifier module

Apparatus and methods that compensate for the effects of gain and phase variations of a high power amplifier in the presence of multicarrier traffic. The calibration system and method impose negligible degradation to the multicarrier traffic processed by the high power amplifier. A calibration signal generator is used to generate a plurality of nondisrupting calibration signals, such as pseudorandom numbers, which are also summed and combined with the multicarrier traffic signals. The plurality of nondisrupting calibration signals are also combined to produce a combined nondisrupting calibration signal. Each of the nondisrupting calibration signals is selectively output and is combined with sampled versions of the amplified multicarrier traffic signals produced by the high power amplifier to despread them. The despread multicarrier traffic signals are then processed in a processor to generate signals indicative of total signal power, intermodulation power, and phase shift of the despread multicarrier traffic signals to determine a current operating point of the high power amplifier on its gain transfer curve. Gain and phase control signals are generated by a processor that are coupled to the gain control and phase control circuits to set the amplifier at its most desirable operating point.

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Los Angeles, CA, United States of America

Arnold L Berman