United States of America As Represented by the Secretary of the Air Force

Stephen L Hary

James B Y Tsui

David M Lin

John M Emmert

Keith M Graves

Nicholas A Pequignot

A moderate cost and complexity digital radio receiver system having enhanced instantaneous dynamic range response to the receipt of simultaneous signals and also providing large single signal dynamic range. Multiple signal instantaneous dynamic range improvement is achieved through use of a suppressed zero signal amplitude representation arrangement having a selected number of signal amplitude representing digital bits rather than the larger entire array of digital output bits of the receiver system's analog to digital converter. Digital apparatus for accomplishing the selection of desired high order bits from the analog to digital converter output is also disclosed in detail. Use of a 'Monobit' and related simplified Fourier transformation radio receivers as disclosed in identified previous patents of the recited inventors and colleagues is preferred for embodying the digital radio receiver circuit included in a present system.

Digital receiver instantaneous dynamic range enhancement

A Fourier transformation arrangement usable in an electronic warfare radio receiver for analyzing spectral content of multiple transmitter-sourced brief duration incoming signals for their signal characteristics. The disclosed Fourier transformation arrangement includes approximated Kernel function values disposed in a significant plurality of locations about a real-imaginary coordinate axis origin according to disclosed locating principles. The points are displaced from the origin by magnitudes having real and imaginary component lengths of powers of two commencing with zero. Multiplication involving a power of two component length during a Kernel function utilization are preferably achieved by way of an expanded binary shift multiplication algorithm in lieu of a full fledged digital multiplication algorithm. A group of guiding principles for selecting desirable approximation Kernel function locations is included.

Kernel function approximation and receiver

A digital cueing radio receiver system embodied using digital memory in lieu of analog delay lines and thereby avoiding delay line implementation difficulties. The cueing receiver system includes a wideband receiver portion providing an output signal employed for tuning a narrowband receiver portion of the system. Signal delay enabling use of the wideband receiver portion output signals for tuning the narrow band receiver portion selection frequency is provided by a digital memory circuit operating on analog-to-digital converted samples of input signal data of the receiver system. Approximated unity value related mathematical multiplication free Kernel function values are employed in the Fourier transformation. Avoidance of analog delay line-elements in embodying the system is a significant practical advantage of the invention.

Digital cueing receiver

A global position system radio receiver achieved through use of an electronic warfare receiver, and particularly one of the electronic warfare receiver output frequency channels, as a front-end signal processor for the global position system receiver. Electronic warfare receiver channel selection for such usage is described and the attenuating effect of electronic warfare receiver channel center frequency and global position system signal frequency differences are considered. A favorable comparison of present invention and conventional global position system receiver-generated results in processing a global position system signal are included along with control of a sampling frequency characteristic within the electronic warfare receiver in order to align global position system signal frequency and electronic warfare receiver channel location to an electable better degree.

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Dayton, OH, United States of America

Stephen L Hary