Implementation of a multi-channel biomagnetic measurement system using DSP technology

McKay, Jim; Vrba, Jan; Betts, K.; Burbank, M. B.; Lee, S.; Mori, Keiichiro; Nonis, D.; Spear, Peter D.; Uriel, Y.

doi:10.1109/ccece.1993.332268

Cited by 8 publications

(5 citation statements)

References 2 publications

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“…If magnetometers are used and/or magnetic shielding is poor at low frequency, or a true dc bandwidth is required, a higher dynamic range is desirable. For instance the neuromagnetometer developed by CTF (McKay et al 1993) is designed to be operated also in an unshielded environment. To achieve the required dynamic range, the ADC is carried out with 32-bit resolution, thus resulting in a dynamic range larger than 190 dB.…”

Section: Analogue-to-digital Conversionmentioning

confidence: 99%

Magnetoencephalography - a noninvasive brain imaging method with 1 ms time resolution

Gratta

Pizzella

Tecchio³

et al. 2001

Rep. Prog. Phys.

110

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The basics of magnetoencephalography (MEG), i.e. the measurement and the analysis of the tiny magnetic fields generated outside the scalp by the working human brain, are reviewed. Three main topics are discussed: (1) the relationship between the magnetic field and its generators, including on one hand the neurophysiological basis and the physical theory of magnetic field generation, and on the other hand the techniques for the estimation of the sources from the magnetic field measurements; (2) the instrumental techniques and the laboratory practice of neuromagnetic field measurement and (3) the main applications of MEG in basic neurophysiology as well as in clinical neurology.

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Section: Analogue-to-digital Conversionmentioning

confidence: 99%

Magnetoencephalography - a noninvasive brain imaging method with 1 ms time resolution

Gratta

Pizzella

Tecchio³

et al. 2001

Rep. Prog. Phys.

110

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“…The main advantages of this technique are a large dynamic range, simple and modular electronics, and uniform performances across channels. Figure 15 shows how this method works: the FLL consists of a preamplifier coupled to the SQUID output, an A/D converter, a digital signal processor (DSP) acting as the integrator, a flux quantum counter and a D/A converter in the feedback loop [75]. The flux quantum count is based on the periodic flux-to-voltage characteristics of the SQUID.…”

Section: Digital Feedbackmentioning

confidence: 99%

“…The dewar can be tilted by up to 90 • , in order to perform measurements both seated and in a supine position. The readout electronics are based on FLL with digital feedback and flux quantum count [75], as described in section 5.3.5; the A/D conversion dynamic range is 32 bits, 20 of which are used for a flux quantum, meaning a dynamic range larger than 190 dB. The small number of R97 analogue components used in the SQUID electronics allows us to obtain homogeneous performance among channels, which is necessary for a reliable software noise reduction.…”

Section: Multichannel Systems For Megmentioning

confidence: 99%

SQUID systems for biomagnetic imaging

Pizzella

Penna

Gratta

et al. 2001

Supercond. Sci. Technol.

109

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This review paper illustrates the different SQUID based systems used for biomagnetic imaging. The review is divided into nine sections. The first three sections are introductory: section 1 is a short overview of the topic; section 2 summarizes how the biomagnetic fields are generated and what are the basic mathematical models for the field sources; section 3 illustrates the principles of operation of the SQUID device. Sections 4-8 are specifically devoted to the description of the different systems used for biomagnetic measurements: section 4 discusses the different types of detection coils; section 5 illustrates the SQUID sensors specifically designed for biomagnetic applications together with the necessary driving electronics, with special emphasis on high-temperature superconductivity (HTS) SQUIDs, since HTS devices are still in a developing stage; section 6 illustrates the different noise reduction techniques; section 7 describes the different multichannel sensors presently operating; and, finally, section 8 gives a hint of what kind of physiological and/or clinical information may be gathered by the biomagnetic technique. Section 9 suggests some future trends for the biomagnetic technique.

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“…Further details are given in [3]. The extension of the system's dynamic range is possible by the use of digital SQUID drive electronics [6]. Using the SQUID as part of the analog to digital converter (ADC), it is possible to achieve 32 bit ADC.…”

Section: Dynamic Rangementioning

confidence: 99%

Issues relating to airborne applications of HTS SQUIDs

Foley

Leslie

Binks

et al. 2002

Supercond. Sci. Technol.

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Airborne application of HTS SQUIDs is the most difficult environment for their successful deployment. In order to operate with the sensitivity required for a particular application, there are many issues to be addressed such as the need for very wide dynamic range electronics, motion noise elimination, immunity to large changing magnetic fields and cultural noise sources. This paper reviews what is necessary to achieve an airborne system giving examples in geophysical mineral exploration. It will consider issues relating to device design and fabrication, electronics, dewar design, suspension system requirements and noise elimination methods.

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Implementation of a multi-channel biomagnetic measurement system using DSP technology

Cited by 8 publications

References 2 publications

Magnetoencephalography - a noninvasive brain imaging method with 1 ms time resolution

Magnetoencephalography - a noninvasive brain imaging method with 1 ms time resolution

SQUID systems for biomagnetic imaging

Issues relating to airborne applications of HTS SQUIDs

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