Ultimate Sensitivity And Resolution Of Phosphor/Fiber/Charge-Coupled-Device Systems

Dunham, Mark E.; Sanchez, Philip G.

doi:10.1117/12.7974191

Cited by 3 publications

(2 citation statements)

References 1 publication

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“…15-20]. This process depends greatly on the correlation span in pixels of the desired feature [Dunham and Sanchez, 1987], which is many hundreds of pixels for tracelike features such as our chirp. Therefore, while more sophisticated procedures employing centroiding above a threshold, or weighting of points by amplitude above a threshold may be proposed, we have found simple binary thresholding to be an adequate method of recovering raw •o'(t) down to peak/RMS SNR of 1.5.…”

Section: At This Point It Must Be Noted That the Satellite Data Is Inmentioning

confidence: 99%

Transionospheric signal recognition by joint time‐frequency representation

Qian¹,

Dunham²,

Freeman³

1995

Radio Science

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A challenging problem in signal processing is the detection of impulsive signals which are dispersed by the ionosphere and received by RF satellite sensors. One example of this type of signal is the so‐called transionospheric pulse pair (TIPP), thought to be associated with lightning discharges. Since these dispersed events occur sporadically and typically persist for less than 100 μs, the first objective is to detect or trigger on the signal of interest, thereby reducing the amount of data relayed back to Earth. Difficulties in detecting transionospheric impulses arise from the dispersion of the original signal, which lowers the signal‐to‐noise ratio (SNR), and the need for continuous, real‐time observation. The energy content of TIPPs has been measured from 25 MHz to more than 100 MHz, requiring sampling rates of at least 150 MHz to capture the events. Although these transionospheric signals are easily recognized in the joint time‐frequency domain, the computation involved in time‐frequency transformations prohibits application to a real‐time detector with this sampling rate. Using a joint time‐frequency representation allows us to derive a robust time convolution template to fit transionospheric signals. This template can be used to design matched chirp filter banks, which are optimum with respect to SNR, for detection of transionospheric signals. We believe that a realistic matched filter bank could have a sparse spacing while maintaining good detection ability. This type of detector is also amenable to real‐time analog hardware implementation in conventional finite impulse response (FIR) filter structures. Our work shows that transionospheric signals encountered in real data are effectively detected by matched filter banks. While a specific application is treated here, the methods described are general, and applicable to many problems in signal detection and recognition which treat nonlinearly dispersed signals.

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Section: At This Point It Must Be Noted That the Satellite Data Is Inmentioning

confidence: 99%

Transionospheric signal recognition by joint time‐frequency representation

Qian¹,

Dunham²,

Freeman³

1995

Radio Science

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“…We adopt a simplification by assuming that the effective response varies only with the average signal drive level. The amplifier frequency response is often modeled as a 2-pole linear filter.20 The signal at the output of the video amplifier can be expressed r(x,y) = {q(x,y) + flb(X,y)) * ha(X, 1k) + Ia(X,y) (2) where indicates convolution, ha 5 the video amplifier impulse response,21 and is the amplifier noise source. The corresponding noise power specirum, for a uniform input signal is…”

Section: Introductionmentioning

confidence: 99%

<title>Image signal modulation and noise analysis of CRT displays</title>

Burns

1991

SPIE Proceedings

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Efficiency and resolution of a new readout system for electro-optical devices

Dunham¹

1989

Review of Scientific Instruments

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Results of a new experiment investigating fiber-coupled, astronomical CCD cameras as imaging systems for electro-optic devices are described. These results indicate that single-electron detection is achievable at 10-kV energy and that the resolution can exceed 35-μm FWHM. A system using such a camera to read a matched, high-resolution phosphor is described, and characterizations of the various component efficiencies are given. It is concluded that this system offers formidable competition to microchannel plate intensified systems with respect to dynamic range, absolute sensitivity, and cost.

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Ultimate Sensitivity And Resolution Of Phosphor/Fiber/Charge-Coupled-Device Systems

Cited by 3 publications

References 1 publication

Transionospheric signal recognition by joint time‐frequency representation

Transionospheric signal recognition by joint time‐frequency representation

<title>Image signal modulation and noise analysis of CRT displays</title>

Efficiency and resolution of a new readout system for electro-optical devices

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