Northrop Grumman Systems Corporation

Dorsal Networks, Inc.

William C Phillips

Michael V Pascale

Ronald W Minarik

Kenneth M Schmidt

Benjamin F Weigand

Walter M Dirndorfer

Robert S Prill

Arnold B Siegel

Lee Daniel Feinberg

Brent Ashley Miller

Charles L Hilterbrick

Richard H Nogay

A hybrid interface for handling different types of data streams is disclosed. Both OC192 and OC768 data streams can be transported between terrestrial and submarine systems using hybrid interfaces. Examples include processing branches that use common FEC units, multiplexers, demultiplexers, transmitters and receivers for both types of data streams. WDM channels are allocated in groups for OC768 data stream handling. Time misalignment between received channels within a group is identified and compensated.

Methods and systems for hybrid interfaces and architectures for optical communications

A system that partitions or divides the functions of a radio into channels and divides the functions of each channel into two major functions: 1) antenna interface and power amplification; and 2) hardwired mixing, modulation/demodulation and signal processing and further partitions the mixing through signal processing functions into the functions of a) programmable analog mixing and b) programmable digital modulation/demodulation and signal processing. Control and user interface functions, if needed for a particular application can also be functionally partitioned. A typical received signal pathway will encounter an antenna module, an antenna interface and power amplification module, a receiver module partitioned into an analog submodule that performs mixing and down conversion to produce a common intermediate frequency signal and a digital submodule that further down converts the intermediate frequency signal, demodulates the signal and performs the other signal processing necessary to provide a useful information signal. A typical transmitter pathway includes a transmitter module partitioned into a digital submodule that performs signal processing and modulation and an analog submodule that performs upconversion and mixing, followed by a power amplification and interface module and an antenna module. Control and user interface modules can also be provided along with modules that perform additional processing and information security functions.

Digitally programmable multifunction radio system architecture

A programmable digital radio is configured to perform navigation functions. A receiver in the programmable digital radio receives analog signals from a navigation unit and digitizes the analog signals to produce digital navigation signals. The digital navigation signals are processed digitally and valid navigation information is determined. Processing includes generation of baseband signals including in-phase signals and quadrature signals, AM demodulation, filtering, decimating, demultiplexing, discrete fourier transformation, and function processing according to a selected function. The selected functions may include Localizer, Marker Beacon and Glideslope.

Digitally programmable radio modules for navigation systems

A common transmit module of a programmable digital radio has a digital submodule which receives a bit stream and produces a modulated IF signal, and an analog submodule which receives the modulated IF signal and converts the modulated IF signal to a frequency corresponding to a specific type of radio function. The digital submodule includes (a) a sequential/parallel instruction set processor for signal processing and control, (b) a reconfigurable format unit, and (c) a modulator which receives the output signals of the reconfigurable format unit and produces the modulated oscillation signal. The analog submodule includes (a) a tunable local oscillator that produces a tunable local oscillation signal, (b) fixed local oscillators that produce fixed local oscillation signals, and (c) a mixing unit that receives the modulated IF signal, the tunable local oscillation signal and the fixed local oscillation signals, selectively mixes the fixed local oscillation signals with the modulated oscillation signal to produce non-final IF signals, and mixes a non-final IF signal with the tunable local oscillation signal to produce a final converted signal for transmission at the frequency corresponding to the specific type of radio function.

Common transmit module for a programmable digital radio

A digital submodule is included in a software programmable common receive module for receiving IF signals and producing a serial bit stream. The digital submodule is programmable based on a selected application of a plurality of radio applications and, if present, a selected function of a plurality of functions of the selected radio application. The digital submodule may include an analog to digital converter for converting IF signals received from an analog submodule into digital signals. The digital signals are supplied to a programmable signal processing unit which is configured, according to the selected radio application and, if present, the selected function, to perform control functions, processing and analysis of the digital signals and generate output signals. The output signals are then formatted by a formatting unit producing formatted digital signals. The formatted digital signals are then supplied to a system bus. The programmable signal processing unit may include a digital downconverter for selective use depending on the selected application of radio communication, for generating a base signal. Additionally, a central processing unit is included to perform further signal processing for selected radio application.

Common receive module for a programmable digital radio

A FIR interpolator which uses a zero order hold to add samples in-between original samples of a digital input stream. The use of zero order hold with a FIR interpolator reduces output harmonics as compared to the use of conventional zero fill. Moreover, a computation method has been developed to greatly reduce the amount of computation needed by combining the zero order hold and the FIR filter. The output of the FIR interpolator can then be interpolated by a Spline interpolator to further interpolate the input stream. The combination of zero order hold FIR interpolation with Spline interpolation provides an efficient, cost effective technique of interpolating a digital input stream while producing relatively small output harmonics.

Fir interpolator with zero order hold and fir-spline interpolation

A programmable digital radio is configured to perform transponder functions. A receiver in the programmable digital radio receives analog signals from an interrogator and digitizes the analog signals to produce digital interrogation signals. The digital interrogation signals are processed digitally and valid interrogations are detected. Processing includes detection of pulses, determination of each pulse's threshold, determination of intervals between pulses and whether the intervals meet mode criteria, and determination of priority of output of digital messages encoded in the pulses. At least one message is supplied to a transmit module in the programmable radio. The transmit module performs diversity processing on the received message to determine to which received signal to reply, produces reply data and modulates the reply data to produce intermediate frequency signals. The intermediate frequency signals are then converted to analog signals which are transmitted to the interrogator.

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Ellicott City, MD, United States of America

William C Phillips