Dynamic Range Enhancement of Photodiode Array Spectra

1987 ◽  
Vol 41 (8) ◽  
pp. 1383-1387 ◽  
Author(s):  
Douglas F. Wirsz ◽  
R. J. Browne ◽  
M. W. Blades
Keyword(s):  
Data Acquisition ◽  
Dynamic Range ◽  
Computer Control ◽  
Photomultiplier Tube ◽  
Integration Time ◽  
Single Spectrum ◽  
Noise Floor ◽  
Photodiode Array

The dynamic range of the photodiode array is typically 30 dB. In situations requiring a dynamic range greater than 30 dB, the photomultiplier tube is a popular alternative, but the advantage of multiwavelength simultaneous data acquisition—possible with a photodioide array—is lost. A method has been developed to enhance the dynamic range of spectra taken with the use of a photodiode array. A set of spectra is collected under computer control at varied integration times, and the optimum integration time is chosen individually for each detecting element. As a result, an improvement in the suppression of the noise floor is achieved, leading to a single spectrum with an enhanced dynamic range of 50 dB.

scholarly journals Small All-Range Lidar for Asteroid and Comet Core Missions

Sensors ◽  
2021 ◽  
Vol 21 (9) ◽  
pp. 3081
Author(s):  
Xiaoli Sun ◽  
Daniel R. Cremons ◽  
Erwan Mazarico ◽  
Guangning Yang ◽  
James B. Abshire ◽  
...  
Keyword(s):  
Fiber Lasers ◽  
Dynamic Range ◽  
Photon Counting ◽  
Avalanche Photodiode ◽  
Integration Time ◽  
Sample Collection ◽  
Long Distance ◽  
Linear Mode ◽  
Internal Gain ◽  
Pseudo Noise

We report the development of a new type of space lidar specifically designed for missions to small planetary bodies for both topographic mapping and support of sample collection or landing. The instrument is designed to have a wide dynamic range with several operation modes for different mission phases. The laser transmitter consists of a fiber laser that is intensity modulated with a return-to-zero pseudo-noise (RZPN) code. The receiver detects the coded pulse-train by correlating the detected signal with the RZPN kernel. Unlike regular pseudo noise (PN) lidars, the RZPN kernel is set to zero outside laser firing windows, which removes most of the background noise over the receiver integration time. This technique enables the use of low peak-power but high pulse-rate lasers, such as fiber lasers, for long-distance ranging without aliasing. The laser power and the internal gain of the detector can both be adjusted to give a wide measurement dynamic range. The laser modulation code pattern can also be reconfigured in orbit to optimize measurements to different measurement environments. The receiver uses a multi-pixel linear mode photon-counting HgCdTe avalanche photodiode (APD) array with near quantum limited sensitivity at near to mid infrared wavelengths where many fiber lasers and diode lasers operate. The instrument is modular and versatile and can be built mostly with components developed by the optical communication industry.

Computer control and data acquisition of the heavy ion beam probe (abstract)

1995 ◽  
Vol 66 (1) ◽  
pp. 315-315
Author(s):  
D. R. Demers ◽  
P. M. Schoch ◽  
T. P. Crowley ◽  
A. Ouroua
Keyword(s):  
Data Acquisition ◽  
Ion Beam ◽  
Computer Control ◽  
Heavy Ion ◽  
Heavy Ion Beam ◽  
Heavy Ion Beam Probe

Snapshot Imaging with the Australia Telescope Compact Array

1995 ◽  
Vol 12 (2) ◽  
pp. 227-238 ◽  
Author(s):  
A. M. Burgess ◽  
R. W. Hunstead
Keyword(s):  
Dynamic Range ◽  
Angular Size ◽  
Integration Time ◽  
More Care ◽  
Snapshot Imaging ◽  
The One ◽  
5 Ghz ◽  
Total Integration ◽  
Deconvolution Techniques ◽  
Compact Array

AbstractRadio snapshot imaging is an efficient observing method which allows several sources to be observed in the one session. Snapshot observing with the Australia Telescope Compact Array (ATCA) involves special difficulties, as the small number of antennas combined with the short total integration time leads to high sidelobe levels in the raw images. The images can be improved markedly by standard deconvolution techniques, but more care is required in their use because of the difficulty in distinguishing real emission from artefacts. This study, based on a set of snapshot observations of strong sources at 5 GHz, gives guidance on both the planning of observations and the data reduction. We show that snapshot imaging with the 6 km ATCA can achieve a dynamic range of 100–200:1 provided certain conditions are met, namely a peak flux density > 100 mJy, an angular size ≤ 30″ and an hour-angle coverage spanning at least six well-separated 5-minute cuts. When observing weak sources it is essential for calibration sources to be selected carefully and observed frequently.

Modelling of Io’s Atmosphere for the IVO Mission

2021 ◽  
Author(s):  
Peter Wurz ◽  
Audrey Vorburger ◽  
Alfred McEwen ◽  
Kathy Mandt ◽  
Ashley Davies ◽  
...  
Keyword(s):  
Mass Loss ◽  
Dynamic Range ◽  
Detection Threshold ◽  
Mass Range ◽  
Mission Design ◽  
Integration Time ◽  
Many Worlds ◽  
Initial State ◽  
Atmospheric Escape ◽  
Tidal Heating

<p>The Io Volcano Observer (IVO) is a proposed NASA Discovery-class mission (currently in Phase A), that would launch<span> in early 2029, arrive at </span> Jupiter in the early 2033, and perform ten flybys of Io while in Jupiter's orbit. IVO's mission motto is to 'follow the heat', shedding light onto tidal heating as a fundamental planetary process. Specifically, IVO will determine (i) how and where heat is generated in Io's interior, (ii) how heat is transported to the surface, and (iii) how Io has evolved with time. The answers to these questions will fill fundamental gaps in the current understanding of the evolution and habitability of many worlds across our Solar System and beyond where tidal heating plays a key role, and will give us insight into how early Earth, Moon, and Mars may have worked.</p><p>One of the five key science questions IVO will be addressing is determining Io's mass loss via atmospheric escape. Understanding Io's mass loss today will offer information on how the chemistry of Io has been altered from its initial state and would provide useful clues on how atmospheres on other bodies have evolved over time. IVO plans on measuring Io's mass loss in situ with the Ion and Neutral Mass Spectrometer (INMS), a successor to the instrument currently being built for the JUpiter Icy moons Explorer (JUICE). INMS will measure neutrals and ions in the mass range 1 – 300 u, with a mass resolution (M/ΔM) of 500, a dynamic range of > 10<sup>5</sup>, a detection threshold of 100 cm<sup>–3</sup> for an integration time of 5 s, and a cadence of 0.5 – 300 s per spectrum.</p><p>In preparation for IVO, we model atmospheric density profiles of species known and expected to be present on Io's surface from both measurements and previous modelling efforts. Based on the IVO mission design, we present three different measurement scenarios for INMS we expect to encounter at Io based on the planned flybys: (i) a purely sublimated atmosphere, (ii) the 'hot' atmosphere generated by lava fields, and (iii) the plume gases resulting from volcanic activity. We calculate the expected mass spectra to be recorded by INMS during these flybys for these atmospheric scenarios.</p>

scholarly journals COMPUTER CONTROL AND DATA ACQUISITION OF A TIDAL MODEL

1972 ◽  
Vol 1 (13) ◽  
pp. 133
Author(s):  
E.R. Funke
Keyword(s):  
Data Acquisition ◽  
Mechanical Engineering ◽  
Computer Control ◽  
Feedback Controller ◽  
Adaptive Feedback ◽  
Tidal Model ◽  
Computer Based ◽  
And Control ◽  
St Lawrence River ◽  
Diurnal Tides

A large tidal model of the St. Lawrence River covering the region from Montreal to lie du Bic is connected directly to a mini computer for data acquisition and control of the tidal boundary. Some of the more important concepts for the design and operation of a computer based system for this application are described. Details of an adaptive feedback controller for diurnal tides are given. A 16 mm film (N.R.C.-Division of Mechanical Engineering, film no. HYP 620, same title) describes the instrumentation and operation of the model. A report (N.R.C.-Division of Mechanical Engineering, Report No. MH-110, same title) provides further details of this system.

scholarly journals High Dynamic Range Imaging with TDC-Based CMOS SPAD Arrays

Instruments ◽  
2019 ◽  
Vol 3 (3) ◽  
pp. 38 ◽  
Author(s):  
Majid Zarghami ◽  
Leonardo Gasparini ◽  
Matteo Perenzoni ◽  
Lucio Pancheri
Keyword(s):  
Dynamic Range ◽  
Single Photon ◽  
Photon Counting ◽  
Complementary Metal Oxide Semiconductor ◽  
High Dynamic Range ◽  
Oxide Semiconductor ◽  
Photon Flux ◽  
Integration Time ◽  
Rate Dependent ◽  
High Dynamic

This paper investigates the use of image sensors based on complementary metal–oxide–semiconductor (CMOS) single-photon avalanche diodes (SPADs) in high dynamic range (HDR) imaging by combining photon counts and timestamps. The proposed method is validated experimentally with an SPAD detector based on a per-pixel time-to-digital converter (TDC) architecture. The detector, featuring 32 × 32 pixels with 44.64-µm pitch, 19.48% fill factor, and time-resolving capability of ~295-ps, was fabricated in a 150-nm CMOS standard technology. At high photon flux densities, the pixel output is saturated when operating in photon-counting mode, thus limiting the DR of this imager. This limitation can be overcome by exploiting the distribution of photon arrival times in each pixel, which shows an exponential behavior with a decay rate dependent on the photon flux level. By fitting the histogram curve with the exponential decay function, the extracted time constant is used to estimate the photon count. This approach achieves 138.7-dB dynamic range within 30-ms of integration time, and can be further extended by using a timestamping mechanism with a higher resolution.

scholarly journals Computer simulation of low‐frequency electromagnetic data acquisition

Geophysics ◽  
1983 ◽  
Vol 48 (9) ◽  
pp. 1219-1232 ◽  
Author(s):  
William A. San Filipo ◽  
Gerald W. Hohmann
Keyword(s):  
Computer Simulation ◽  
Data Acquisition ◽  
Dynamic Range ◽  
Low Frequency ◽  
Noise Removal ◽  
Digital Data ◽  
Low Frequencies ◽  
Pass Filter ◽  
Natural Field ◽  
Field Noise

Computer simulation of low‐frequency electromagnetic (EM) digital data acquisition in the presence of natural field noise demonstrates several important limitations and considerations. Without a remote reference noise removal scheme, it is difficult to obtain an adequate ratio of signal to noise below 0.1 Hz for frequency‐domain processing and below 0.3 Hz base frequency for time‐domain processing for a typical source‐receiver configuration. A digital high‐pass filter substantially facilitates rejection of natural field noise above these frequencies; however, at lower frequencies where much longer stacking times are required, it becomes ineffective. Use of a remote reference to subtract natural field noise extends these low‐frequency limits by one decade, but the remote reference technique is limited by the resolution and dynamic range of the instrumentation. Gathering data in short segments so that natural field drift can be offset for each segment allows a higher gain setting to minimize dynamic range problems. The analysis is also applicable to the induced polarization technique in which similar problems arise at low frequencies in the presence of telluric noise.

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