Sentel Corporation

John P Smith

Theodore L Harwood

Michael A Maiuzzo

William G Duff

Jesse David Warner

Arthur Light

Art Light

Darrel Crapps

Troy Van Liere

A bit quality evaluator receives a sequence of bits. The bit sequence is provided to a decoding device that performs soft decision convolutional decoding on the sequence of bits. An off track event detector detects an occurrence of a trellis decode path change during the convolutional decoding operation and identifies a first symbol proximate corresponding to the occurrence of the trellis decode path change. An erasure decision circuit identifies at least the first symbol for erasure. The output of the first decoder and the erasure decision circuit are received at a second decoder, which decoder decodes the output of the first decoder after erasing at least the first symbol. The erasure decision circuit may also identify additional symbols for erasure using performance measures of the trellis decode path and using quality measures of the sequence of bits.

Fault tolerant decoding method and apparatus

A bit quality evaluator receives a sequence of bits. A quality measure is assigned to each bit within the sequence. The bit sequence and the quality measures are provided to a decoding device that performs soft decision convolutional decoding on the sequence of bits using the quality measure. An off-path detector detects an occurrence of a trellis decode path change during the convolutional decoding operation and identifies a first symbol proximate corresponding to the occurrence of the trellis decode path change. An erasure decision circuit identifies at least the first symbol for erasure. The output of the first decoder and the erasure decision circuit are received at a second decoder, which decoder decodes the output of the first decoder after erasing at least the first symbol. The erasure decision circuit may also identify additional symbols for erasure based on performance measures of the trellis decode path and the quality measure of the sequence of bits.

Fault tolerant decoding method and apparatus including use of quality information

An ultra wideband (UWB) jamming system comprises a processor, a memory, a pulse generator, one or more UWB transmitters, and one or more UWB antennas. In an exemplary embodiment of the present invention, the RF signals of a threat transmission or an RF-triggered explosive device (RTED) are evaluated and a set of interference parameters defined for the RF signal of that device. The interference parameters are predetermined to interfere with the reception or transmission of the RF signal. The interference parameters are sent to a pulse generator that drives one or more UWB transmitters to generate a signal has a statistically high probability of jamming or introducing an error in the threatening transmission.

Method and apparatus for protecting personnel and material from RF-based threats using ultra-wideband (UWB) transmission

The test results found that the EMI impact depended on the UWB power that fell within the receiver passband. Specifically, EMI occurred when the average power in the receiver passband was approximately equal to the desired signal level of the receiver. One waveform, TW7, did not cause EMI because the average power was too low. Three waveforms, TW1, TW2, and TW6 only caused EMI when the receiver was tuned to the frequency of the UWB spectral component. Three waveforms, TW3, TW4, and TW5, caused EMI at all receiver frequencies. As noted, these tests were performed to determine the susceptibility of various RF receiver (radars and communications systems) devices to UWB signals. The tests were not intended to evaluate the use of UWB signals for jamming purposes.

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Millersville, MD, United States of America

John P Smith