Phillip E. Pace

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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 analogto-digital converter (ADC) technology restrict the total bandwidth that can be(More)
In a previous cross-sectional survey, up to 15% of shipyard painters were found to have mild anemia or granulocytopenia, mostly acquired since employment. Environmental studies had suggested a possible etiologic role for ethylene glycol ethers, solvents to which the men were heavily exposed and which have established myelotoxic potential. To exclude(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)
The relationship between the discrete Fourier transform (DFT) and the symmetrical number system (SNS) is examined as a means of resolving single-frequency undersampling aliases (f > fs=2). It is shown that the DFT naturally encodes the frequency information of a signal in a format that is in the same form as the SNS. Consequently, aliases that result from(More)
AbstructHigh 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)
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)