7,107 research outputs found
MicroTCA implementation of synchronous Ethernet-Based DAQ systems for large scale experiments
Large LAr TPCs are among the most powerful detectors to address open problems
in particle and astro-particle physics, such as CP violation in leptonic
sector, neutrino properties and their astrophysical implications, proton decay
search etc. The scale of such detector implies severe constraints on their
readout and DAQ system. In this article we describe a data acquisition scheme
for this new generation of large detectors. The main challenge is to propose a
scalable and easy to use solution able to manage a large number of channels at
the lowest cost. It is interesting to note that these constraints are very
similar to those existing in Network Telecommunication Industry. We propose to
study how emerging technologies like ATCA and TCA could be used in
neutrino experiments. We describe the design of an Advanced Mezzanine Board
(AMC) including 32 ADC channels. This board receives 32 analogical channels at
the front panel and sends the formatted data through the TCA backplane
using a Gigabit Ethernet link. The gigabit switch of the MCH is used to
centralize and to send the data to the event building computer. The core of
this card is a FPGA (ARIA-GX from ALTERA) including the whole system except the
memories. A hardware accelerator has been implemented using a NIOS II P
and a Gigabit MAC IP. Obviously, in order to be able to reconstruct the tracks
from the events a time synchronisation system is mandatory. We decided to
implement the IEEE1588 standard also called Precision Timing Protocol, another
emerging and promising technology in Telecommunication Industry. In this
article we describe a Gigabit PTP implementation using the recovered clock of
the gigabit link. By doing so the drift is directly cancelled and the PTP will
be used only to evaluate and to correct the offset.Comment: Talk presented at the 2009 Real Time Conference, Beijing, May '09,
submitted to the proceeding
FPGA based data acquisition system for COMPASS experiment
This paper discusses the present data acquisition system (DAQ) of the COMPASS
experiment at CERN and presents development of a new DAQ. The new DAQ must
preserve present data format and be able to communicate with FPGA cards. Parts
of the new DAQ are based on state machines and they are implemented in C++ with
usage of the QT framework, the DIM library, and the IPBus technology. Prototype
of the system is prepared and communication through DIM between parts was
tested. An implementation of the IPBus technology was prepared and tested. The
new DAQ proved to be able to fulfill requirements.Comment: 8 pages, CHEP 201
Satellite range delay simulator for a matrix-switched time division multiple-access network simulator
The Systems Integration, Test, and Evaluation (SITE) facility at NASA Lewis Research Center is presently configured as a satellite-switched time division multiple access (SS-TDMA) network simulator. The purpose of SITE is to demonstrate and evaluate advanced communication satellite technologies, presently embodied by POC components developed under NASA contracts in addition to other hardware, such as ground terminals, designed and built in-house at NASA Lewis. Each ground terminal in a satellite communications system will experience a different aspect of the satellite's motion due mainly to daily tidal effects and station keeping, hence a different duration and rate of variation in the range delay. As a result of this and other effects such as local oscillator instability, each ground terminal must constantly adjust its transmit burst timing so that data bursts from separate ground terminals arrive at the satellite in their assigned time slots, preventing overlap and keeping the system in synchronism. On the receiving end, ground terminals must synchronize their local clocks using reference transmissions received through the satellite link. A feature of the SITE facility is its capability to simulate the varying propagation delays and associated Doppler frequency shifts that the ground terminals in the network have to cope with. Delay is achieved by means of two NASA Lewis designed and built range delay simulator (RDS) systems, each independently controlled locally with front panel switches or remotely by an experiment control and monitor (EC/M) computer
Digitally modulated bit error rate measurement system for microwave component evaluation
The NASA Lewis Research Center has developed a unique capability for evaluation of the microwave components of a digital communication system. This digitally modulated bit-error-rate (BER) measurement system (DMBERMS) features a continuous data digital BER test set, a data processor, a serial minimum shift keying (SMSK) modem, noise generation, and computer automation. Application of the DMBERMS has provided useful information for the evaluation of existing microwave components and of design goals for future components. The design and applications of this system for digitally modulated BER measurements are discussed
The S2 VLBI Correlator: A Correlator for Space VLBI and Geodetic Signal Processing
We describe the design of a correlator system for ground and space-based
VLBI. The correlator contains unique signal processing functions: flexible LO
frequency switching for bandwidth synthesis; 1 ms dump intervals, multi-rate
digital signal-processing techniques to allow correlation of signals at
different sample rates; and a digital filter for very high resolution
cross-power spectra. It also includes autocorrelation, tone extraction, pulsar
gating, signal-statistics accumulation.Comment: 44 pages, 13 figure
- …