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Title: Self-adaptive sampling rate data acquisition in JET's correlation reflectometer

Journal Article · · Review of Scientific Instruments
DOI:https://doi.org/10.1063/1.2965011· OSTI ID:21266652
; ; ;  [1];  [2];  [3];  [4]
  1. Grupo de Investigacion en Instrumentacion y Acustica Aplicada, Universidad Politecnica de Madrid, Ctra. Valencia Km 7, 28031 Madrid (Spain)
  2. Asociacion EURATOM/CIEMAT para Fusion, Avda. Complutense 22, 28040 Madrid (Spain)
  3. Consorzio RFX-Associazione EURATOM ENEA per la Fusione, Corso Stati Uniti 4, Padova 35127 (Italy)
  4. Associacao EURATOM/IST, Instituto de Plasmas e Fusao Nuclear, 1049-001 Lisbon (Portugal)

Data acquisition systems with self-adaptive sampling rate capabilities have been proposed as a solution to reduce the shear amount of data collected in every discharge of present fusion devices. This paper discusses the design of such a system for its use in the KG8B correlation reflectometer at JET. The system, which is based on the ITMS platform, continuously adapts the sample rate during the acquisition depending on the signal bandwidth. Data are acquired continuously at the expected maximum sample rate and transferred to a memory buffer in the host processor. Thereafter the rest of the process is based on software. Data are read from the memory buffer in blocks and for each block an intelligent decimation algorithm is applied. The decimation algorithm determines the signal bandwidth for each block in order to choose the optimum sample rate for that block, and from there the decimation factor to be used. Memory buffers are used to adapt the throughput of the three main software modules (data acquisition, processing, and storage) following a typical producer-consumer architecture. The system optimizes the amount of data collected while maintaining the same information. Design issues are discussed and results of performance evaluation are presented.

OSTI ID:
21266652
Journal Information:
Review of Scientific Instruments, Vol. 79, Issue 10; Conference: HTPD08: 17. topical conference on high-temperature plasma diagnostics, Albuquerque, NM (United States), 11-15 May 2008; Other Information: DOI: 10.1063/1.2965011; (c) 2008 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0034-6748
Country of Publication:
United States
Language:
English