Northrop Grumman Systems Corporation

Trw Limited

Bert K Oyama

William Marvin Skones

Mark Kintis

Andrew Donovan Smith

Vincent C Moretti

Donald R Martin

Shimen K Claxton

Craig R Talbott

Ronald P Smith

Barry Ross Allen

David Joseph Brunone

Eric L Upton

A receiver ( ) for a wireless telecommunications system that provides relatively wideband signal processing of received signals without increased signal distortion so that multiple received signals can be simultaneously processed. The receiver ( ) includes a specialized LNA ( ), frequency down-converter ( ) and ADC ( ) to perform the wideband signal processing while maintaining receiver performance. The frequency down-converter ( ) employs a suitable mixer ( ), BPA ( ), attenuator ( ), and transformer ( ) that are tuned to provide the desired frequency down-conversion and amplitude control over the desired wideband. The down-converter devices are selected depending on the particular performance criteria of the ADC ( ). A specialized digital channelizer ( ) is included in the receiver ( ) that receives the digital signal from the ADC ( ), and separates the signals into the multiple channels. In one embodiment, the frequency down-conversion is performed in a single down-conversion process, and the ADC ( ) employs delta-sigma processing to provide digital conversion over the complete frequency band. In an alternate embodiment, the frequency down-conversion is performed in a double down-conversion process so that a less complex ADC ( ) can be used.

Wireless telecommunications multi-carrier receiver architecture

Receiver including frequency down-converter and analog-to-digital converter for a wireless telecommunication system

A receiver ( ) for a wireless telecommunications system that provides relatively wideband signal processing of received signals without increased signal distortion so that multiple received signals can be simultaneously processed. The receiver ( ) includes a specialized LNA ( ), frequency down-converter ( ) and ADC ( ) to perform the wideband signal processing while maintaining receiver performance. A specialized digital channelizer ( ) is included in the receiver ( ) that receives the digital signal from the ADC ( ), and separates the signals into the multiple channels. In one embodiment, the frequency down-conversion is performed in a single down-conversion process, and the ADC ( ) employs delta-sigma processing to provide digital conversion over the complete frequency band.

Multi-carrier receiver including an analog-to-digital converter for a wireless telecommunication system

Architecture for multi-carrier receiver

Multi-carrier receiver for a wireless telecommunication system

An analog-to-digital converter ( ) that employs delta-sigma technology, and has particular use in a receiver for a wireless telecommunications system. The converter ( ) includes a delta-sigma modulator ( ), having a summing junction ( ) that receives the analog input signal to be converted. A feedback from the output of a comparator ( ) is subtracted from the analog input signal to generate a difference signal that is then filtered, amplified and applied to the comparator ( ) for digital conversion. A sample and hold circuit ( ) receives the difference signal and holds the signal for a predetermined period of time so that the input to the comparator ( ) is stable. A differential limiting amplifier ( ) is employed to make the high data rate output of the comparator ( ) stable. The differential limiting amplifier ( ) can be within the comparator ( ) itself, or in the feedback path. In one embodiment, the differential amplifier ( ) employs a Schottky diode clamp ( ).

Continuous time delta-sigma modulator

A circuit arrangement for suppressing spurious frequency components of an analog output of a digital-to-analog converter (DAC) features a track-and-reset sampling circuit coupled between the output of the DAC and a linearized differential buffer amplifier circuit including a filter circuit for minimizing high frequency distortion normally accompanying the output of a DAC operating at high frequencies, such as on the order of 500 MHz.

Distortion suppressor for digital-to-analog converter

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Torrance, CA, United States of America

Bert K Oyama