High-speed Sampler Research Articles

First-Year Density and Growth as They Relate to Recruitment of White Perch to the Adult Stock in Oneida Lake, New York, 1968–2011

Recruitment of fish to the adult stock is often determined early in life, and identifying relationships between first-year abundance and subsequent recruitment has significant implications for monitoring and management. Despite the importance of White Perch Morone americana as both predator and prey in systems where they are abundant, relatively little has been published on their early life history, and their recruitment patterns are generally not well understood. We use data over a period of 44 years to investigate factors related to first-year density and growth of White Perch and their recruitment to the adult stock in Oneida Lake, New York. Simple linear regression was used to examine the relationships between select physical and biological factors and first-year density and growth of White Perch estimated from Miller high-speed sampler and trawl surveys and estimates of year-class recruitment to the adult stock determined from gill-net surveys. Akaike's information criterion corrected for small sample size was then used to compare different model structures for predicting age-0 White Perch density and growth and recruitment to the adult stock. Year-classes that were dense at the larval stage tended to have higher densities as juveniles and higher recruitment to the adult stock. Year-classes with higher first-year densities grew slower and experienced higher mortality, but mortality did not compensate for the higher initial densities. The model that best explained White Perch recruitment to the adult stock was composed of larval density and predator biomass, indicating White Perch year-class strength is at least partly determined at the larval stage or earlier in Oneida Lake, and later interactions serve largely to modify initial differences. Received July 29, 2015; accepted December 1, 2015

A high speed sampler for sub-sampling IR-UWB receiver

A high speed sampler for a sub-sampling impulse radio UWB receiver is presented. In this design, the sampler uses a time-interleaved topology with a single track and hold circuit, full custom clock generator, and offset cancelled comparator. These three main blocks are also discussed and analyzed. The circuit was fabricated in 0.13 μm CMOS technology. Measurement results indicate that the sampler achieves a maximum 3 GS/s sampling rate. The power consumption of the sampler is 27 mW under a supply voltage of 1.2 V. The total chip area including pads is 1.4 × 0.97 mm2.

Impedance of Transfer Standards Used in the Calibration of High-Speed Samplers and Pulse Generators

The impedance of the calibration artifact or transfer standard (TS; pulse generator or sampler) is often ignored in high-speed pulse metrology. Using an air line as an integral part of the TS for providing a known impedance for calibration of other instruments is described. The utility of this method is compared to that of using a TS for which its impedance is determined by some other instrument.

Abundance and Distribution Patterns of Scylla spp. Larvae in the Lawele Bay, Southeast Sulawesi, Indonesia

A study on the dynamics of the zoeae larvae of Scylla spp. was conducted in Lawele Bay, Southeast Sulawesi from November 1999 to September 2000, to determine the spatial and temporal patterns of abundance of the zoeae larvae of Scylla spp. and to examine their relationship with water parameters. Sampling was done during flood and ebb tides using a modified miller net high speed sampler with 300 µm mesh. Temperature, salinity and pH were measured at the surface and taken parallel to each plankton haul. The results showed that zoeal abundance was higher during flood tide than ebb tide. Seasonal abundance of the zoeae had three peaks belonging to the dry season (south monsoon), one in March as minor peak and the other two in June and in November as major and moderate peaks, respectively. Water salinity and pH were significantly correlated with zoeal abundance in the respective flood and ebb tides (p < 0.05). Zoeal abundance decreased toward less saline waters, and were absent at low salinity stations (0.3 – 17.3 ppt). Our results suggest that zoeal prefer seawater for development to the megalopal stage.

MARK5B 시스템을 이용한 전파천문 데이터 처리

In this paper, we describe the radio astronomical data processing system implementation using Mark5B and its development. KASI(Korea Astronomy and Space Science Institute) is constructing the KVN (Korean VLBI Network) until the end of 2007, which is the first VLBI(Very Long Baseline Interferometery) facility in Korea and dedicated for the mm-wave VLBI observation. KVN will adopt the DAS (Data Acquisition System) consisting of digital filter with various function and 1Gsps high-speed sampler to digitize the radio astronomical data for analyzing on the digital filter system. And the analyzed data will be recorded to recorder up to 1Gbps data rates. To test this, we have implemented the system which is able to process 1Gbps data rates and carried out the data recording experiment.

PC를 이용한 소규모 기가비트 VLBI 관측시스템

In this paper, we propose a small-scale Gigabit VLBI observing system for the Korean VLBI Network (KVN) under construction. The system consists of high-speed sampler, IP-VLBI board, PC-VSI board, and software correlator. Radio signal received by receiver is sampled by high-speed sample. at 1 Gsps (Gigabit sample per second) rate with 2 bits quantization. The digitized signal is recorded in PC and the software correlator does the cross correlation. IP-VLBI board will be used for the geodesy VLBI observation, while PC-VSI board is for the astronomical VLBI observation. The PC-VSI board adopts the VSI-H (VLBI Standard Interface Hardware). The proposed system is based on commercial PCs and therefore can be built inexpensively.

The role of the generally unrecognised microprey source as food for larval fish in the Irish Sea

Few studies have studied the food supply to larval fish in the Irish Sea; thus, we have assessed the full prey-field available to larval fish, ranging from protozoa to copepods. Specifically we assessed if fish larvae feed on protozoa, as suggested by others, and if densities of the protozoa and the appropriate size of metazoan prey were previously underestimated. By examining the gutcontents of fish larvae, the prey available to them, and the potential accessibility of prey to fish, we develop a simple food web, presented as a box-model. By doing so, we indicate that the lack of focus on small metazoa and protozoa has underestimated the food available to fish larvae; without these, we might have concluded that prey levels were too low to support the growth of the larval fish assemblage. Our methods were as follows. Sampling was at two sites, off the Isle of Man, with distinct physical and biological structures, soon after fish spawning: the southwest coast, where many species occur in spring-summer (23 April; 6, 19 May; 1, 22 June; 12 July) and the east coast, where only herring larvae occur in September–November (12, 28 October). Microplankton (15–200 μm), mesozooplankton, and larval fish were collected at 1, 15, and 25 m: microplankton with 1.5 L bottles and a 64 μm-mesh net; mesozooplankton and larval fish with a Gulf VII high-speed sampler (280 μm mesh). The 64 μm mesh net, mounted on the Gulf VII, provided simultaneous hauls. Fixed samples were evaluated to determine species composition, abundance, and biomass. Larval fish diet was determined from fish collected by short net hauls: fixed guts were examined and prey, including protozoa, analysed. Using physical data as a guide, plankton data were integrated through the water column to determine standing stocks. Size-based food availability to larval fish was estimated from the gut contents. The role of protozoa was examined, assuming that they are digested at the same rate as metazoan and if they are digested 2.5–10 times faster; increased digestion rates indicated that they contributed substantially to the larval fish diet.

KVN 자료획득을 위한 디지털 처리 시스템

This paper describes the digital back-end system for getting the data to analyze the user observation mode by digitalize the analog data after receiving the space radio using the radio telescope, The received analog data will be digitalized by high-speed sampler with 1 Gsps for 4 channel frequency band of millimeter wave, and the digital data will be transported through the fiber-optic digital transmission system and WDM(wavelength division multiplex) to observation building, The wideband digital FIR(Finite Impulse Response) filters analyze the data for user observation mode to record the data in high-speed recorder with 1 Gbps. In this paper, we introduce the overall system configuration and features combined by various information and communication technology in radio astronomy briefly, which will be adopted by KVN(Korean VLBI Network).

On-chip oscilloscopes for noninvasive time-domain measurement of waveforms in digital integrated circuits

High-speed digital design is becoming increasingly analog. In particular, interconnect response at high frequencies can be nonmonotonic with porch steps and ringing. Crosstalk (both capacitive and inductive) can result in glitches on wires that can produce functional failures in receiving circuits. Most of these important effects are not addressed with traditional automatic test pattern generation (ATPG) and built-in self-test (BIST) techniques, which are limited to the binary abstraction. In this work, we explore the feasibility of integrating primitive sampling oscilloscopes on-chip to provide waveforms on selective critical nets for test and diagnosis. The oscilloscopes rely on subsampling techniques to achieve 10-ps timing accuracy. High-speed samplers are combined with delay-locked loops (DLLs) and a simple 8-bit analog-to-digital converter (ADC) to convert the waveforms into digital data that can be incorporated as part of the chip scan chain. We will describe the design and measurement of a chip we have fabricated to incorporate these oscilloscopes with a high-frequency interconnect structure in a TSMC 0.25-/spl mu/m process. The layout was extracted using Cadence's Assura RCX-PL extraction engine, enabling a comparison between simulated and measured results.

Comparison of acoustic and Miller high-speed sampler estimates of larval fish abundance in Oneida Lake, New York

We compare acoustic measures of target strength (TS) (at 70 kHz) and fish abundance with fish size and abundance obtained from high-speed Miller larval fish samplers in Oneida Lake, New York, collected in June and July, 1995–1999. High-speed Miller samplers showed two peaks in size distributions on all dates, 3–15 and 15–30 mm. Corresponding acoustic TS distributions also showed two peaks, one between −76 and −64 dB and the other between −64 and −52 dB. TS of small yellow perch ( Perca flavescens) 15–30 mm followed expectations from a widely used equation by Love, but this equation overestimated the TS of smaller larvae. Depth distribution in Miller samplers and acoustics were also similar. Abundance estimates obtained with the two methods were highly correlated ( r>0.8) for both fish groups. However, acoustics gave higher abundance estimates than Miller samplers for the smaller fish larvae when densities in the samplers were low. We conclude that reliable estimates of abundance of fish as small as 15 mm are obtainable with acoustics, but that it is difficult to exclude noise or invertebrate targets in abundance estimates of smaller fish larvae.

Zooplankton Abundance and Community Structure Over a 4000 km Transect in the North-east Atlantic

Zooplankton samples were collected by a high speed sampler, the U-Tow, in the north-east Atlantic between 61.6 and 36.7°N during June and July 1996, and were used to examine the causality of spatial distributions along a 4000 km transect. Peak zooplankton abundance and biovolume estimations were associated with a frontal system at 48–52°N, which separated hydrographically distinct water masses. The zooplankton assemblage was dominated by herbivorous/omnivorous taxa in the northern regions, and by carnivorous taxa in the southern regions. Arguments are developed to suggest that the switch in both the zooplankton size structure and trophic status, centred within the frontal region, are consistent with ‘bottom-up’ control of zooplankton size structure in this region of the Atlantic.

Low-jitter trigger system for pulse calibration and intercomparison of high-speed samplers

A low-jitter (<1 ps) trigger system for pulse-waveform-based calibration and intercomparison of high-speed samplers is described. The system uses a commercially available pulse generator and pulse splitter/delay line.

Design, fabrication, and testing of a high-speed analog sampler

The authors describe the design, fabrication, and first successful operation in the gigahertz frequency range of a Josephson-junction-based sampling circuit designed to provide 6 b of resolution ( approximately 35 dB) and 10 GHz or more of bandwidth. The first experimental demonstration of a prototype circuit sampling a sine wave at up to 1 GHz is reported. This sampler has properties that make it amenable to incorporation into complex, mixed-analog/digital integrated circuits. Such a circuit can be used in the implementation of such signal processing subsystem components as a transient waveform data recorder, a programmable analog-binary correlator, and a flash analog-to-digital converter. >

Relative Selectivities of Miller High-Speed Samplers and Light Traps for Collecting Ichthyoplankton

Comparative studies on the relative selectivities of Miller high-speed samplers and light traps in Chemung Lake, Ontario, were made over 29 "site-nights" from May 13 to June 25, 1982. Yellow perch (Perca flavescens), Iowa darter (Etheostoma exile), and pumpkinseed sunfish (Lepomis gibbosus) constituted 97.2% of the 4376 specimens collected. A percent similarity index indicated a high uniformity in the size and species composition of the catch (~70% for much of the study); similarity was least on the earliest sample date (May 13, 3.5%). Smaller darters (&lt;6.0 mm total length) were excluded from the Miller sampler catch. We suggest that extrusion of prolarval and early postlarval darters through the tow nets is responsible for low percent similarity index values in early May. We propose that investigators consider a mixture of passive and active sampling techniques to alleviate existing selectivity biases.

Estimates of Larval-Fish Abundance: Diurnal Variation and Influences of Sampling Gear and Towing Speed

Abstract The influence of net-towing speed on estimates of the abundance of larval Atlantic menhaden Brevoortia tyrannus, spot Leiostomus xanthurus, pinfish Lagodon rhomboides, and Atlantic croaker Micropogonias undulatus was studied in nearshore and estuarine areas of North Carolina. A modified Miller high-speed sampler was towed at speeds ranging from 2 to 12 m/second. In one series, catch increased monotonically with increasing tow speed up to 7 m/second; in a second series, catch increased with speed up to 8 m/second but decreased at higher speeds, possibly because larvae were extruded through the net or deflected by the pressure wave. In additional studies, a slowly towed (2 m/second) 20-cm bongo net was compared to the high-speed sampler during daylight; day and night samples from the high-speed sampler also were compared. These data imply that visual avoidance by larval fish biases estimates of both their abundance and their vertical distribution. The data from all three studies suggest the need to...

CCD sampling of high-frequency broad-band signals

Several CCD signal sampling methods are discussed and a CCD input technique with excellent high-speed sampler characteristics is described. The method, a version of the diode-cutoff technique, is being used in a 200 MHz/8 bit transient digitizer system currently under development. DC based signal bandwidth (3 dB) of 600 to 800 MHz has been achieved along with random aperture uncertainty dispersion (one-sigma) of less than 2 ps. The sampler structure, operation, and experimental test results are described.

Distribution and Abundance of Larval Ciscoes, Coregonus Artedii, and Burbot, Lota Lota, in Oneida Lake

Surveys of pelagic fish larvae were made in Oneida Lake, New York, during 1965-1975 with high-speed samplers. In early May, larval ciscoes, Coregonus artedii, occurred only above 5.5 m and were actively concentrated near the surface in shallow bays. The largest larvae were found at the shallowest sites and almost half the ciscoes were taken in one small, protected bay. By late May, the larvae had moved offshore, although they remained near the surface. The largest ciscoes were then at the deepest sites. This offshore movement was not strongly related to limnological conditions - water temperature, dissolved oxygen, and food (zooplankton) were similar throughout the upper water column of Oneida Lake at this time - but may have been related to size and water currents. Successive estimates of larval cisco populations suggested that offshore recruitment exceeded total mortality during May. Densities of larval burbot, Lota lota, were homogeneous (even at depths greater than 5.5 m) during May. In June, as with ciscoes, greater densities of burbot were found near the surface of the offshore sites. In early May, the largest burbot tended to occur at intermediate depths. Few larval ciscoes or burbot were captured in late June. Populations of larval ciscoes and burbot appear to be disproportionately great in relation to the abundance of adults and may contribute to the persistence of these cold-water species in an eutrophic environment.

Influence of pore size of plankton nets and towing speed on the sampling performance of two high-speed samplers (Delfino I and II) and its consequences for the assessment of plankton populations

The sampling performance of two high-speed samplers, (Delfino I and II), fitted with a calibrated flow meter, was studied in the open Ligurian Sea using a battery comprising 6 such Delfinos linked together. Since, in plankton counts, only those organisms should be counted which are definitely retained in the nets, several techniques for the separation of the organisms which pass through the pore of a net of a given pore size and those which are safely retained were tested. Attempts to separate these two fractions by filtration of the fixed sample through nets of different pore sizes were not successful, as living organisms were able to pass through pore sizes which retained dead organisms. However, optical sizing under the dissecting microscope during counting gave reproducible results. Using this counting technique, the influence of the pore size of plankton nets on the reproducibility of sampling of natural populations was studied. The results obtained show that live plankton passes through the net pores at a size at which fixed plankton is retained. Hence, the minimum retention size for living and dead plankton is different. By comparing samples taken with nets of different pore sizes, and counting the organisms caught according to different sizes, it was possible to determine the minimum retention size of live plankton organisms for several different net pore-sizes. The minimum retention size is, therefore, the smallest pore size at which the organisms of a certain width cannot escape through the pores of the net and are, thus, quantitatively retained in the net. By applying the criterion of minimum retention size, the influence of speed towing on the number of plankton organisms caught was studied. It was shown that the number of organisms which are safely retained, i.e., do not escape through the pores, increased with speed, reaching a plateau at 5 to 7 knots.

Evaluation of the Miller High-Speed Sampler for Sampling Yellow Perch and Walleye Fry

Evaluation of avoidance of Miller samplers towed at 8 mph indicated that avoidance began when yellow perch fry were less than 8 mm long and increased as fry grew larger. Catches were increased by increasing towing speed to 11 mph, by using an electric shocking grid in front of the sampler, by using clear and translucent rather than dark, opaque samplers, and by night sampling. A sampler with an aperture 1.5 times as large as the conventional Miller sampler was not more effective. Avoidance by walleye fry occurred, but was less well defined. Application of the results to the development of sampling techniques is discussed.

A hydrodynamic study of a modified model of the Clarke Jet Net

A hydrodynamic study of a modified model of the Clarke Jet Net, a high speed plankton sampler, was made using a wind tunnel and an IBM 7040. Modifications allowed a somewhat larger amount of water filtered than in the original model. By adjusting the size of the net chamber exhaust (water control aperture), an average net chamber velocity of about 100 cm/sec could be obtained at any cruising speed. The curvature of the towing cable of the deep tow of a high speed sampler seemed to be determined mainly by the cable characteristics. The stability, vertical and horizontal, of the modified model was satisfactory.