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Many radar and communications applications require detection and estimation of signal information across an extremely wide radio frequency (RF) bandwidth. In practice, however, direct digitization of this broadband RF environment is problematic. Physical limitations in analog-to-digital converter (ADC) technology restrict the total bandwidth that can be(More)
In a 3-year survey, respiratory symptoms, spirometry, and methacholine reactivity were measured annually in welders (n = 51) and non-welder controls subjects (n = 54) to determine whether welding-related symptoms are associated with accelerated decline in lung function or changes in airway reactivity. In the cross-workshift study, maximal midexpiratory flow(More)
Repeated methacholine challenge in normal nonasthmatic subjects (who require higher doses of methacholine than do asthmatic subjects to produce a 20 percent decrease in FEV1) can produce progressively diminishing methacholine responsiveness (or tolerance) with serial challenges. To determine whether tolerance to methacholine occurs in asthmatic subjects as(More)
Often used in low probability of intercept continuous waveform (CW) emitters, polyphase modulations can have extremely long code lengths (large processing gain), good sidelobe performance and robust Doppler tolerance. This paper presents an efficient algorithm to autonomously extract the polyphase radar modulation parameters from an intercepted waveform(More)
Abstruct-High performance analog-to-digital converters (ADC's) employ a parallel configuration of analog folding circuits to symmetrically fold the input signal prior to quantization by high speed comparators (analog preprocessing). This paper identifies a new preprocessing approach that can be easily incorporated into the established techniques to provide(More)
In response to the fast improvements in anti-radiation systems and electronic attack systems, radar systems began exploiting low power, wide-band, frequency agility techniques to decrease their intercept probability. This increase in the use of low probability of intercept (LPI) waveforms in current radar systems enforces the intercept receiver to use(More)