Publication

A simple approach to single-channel quadrature detection

Geoffrey Bodenhausen
1977
Journal Articles

Abstract

The modification described by A. G. Redfield and S. D. Kunz (1975) for a dual-channel NMR quadrature detection scheme is used in a single-channel spectrometer by stepping the actual ref. phase of the receiver by 90 Deg between adjacent sample points according to an analogous 4-step cycle. The resulting free induction signal is transformed and phase-cor. by the std. software of a conventional single-channel spectrometer. The modification provides 4 selectable phases of 0, 45, 90, and 135 Deg at a frequency of 1.125 MHz by division of the 4.5-MHz master clock frequency with bistable multivibrators. Applications of this scheme are described: (1) the proton-decoupled 13C spectrum of mesitylene; and (2) a 2-dimensional J spectrum of 13C in enriched MeI obtained in the F2 frequency dimension. [on SciFinder (R)]

Official source

https://infoscience.epfl.ch/entities/publication/294d3a43-8894-46a9-bfa2-90ba632d144b

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Geoffrey Bodenhausen
1977
Journal Articles

Abstract

Official source

https://infoscience.epfl.ch/entities/publication/294d3a43-8894-46a9-bfa2-90ba632d144b

About this result

Related concepts (32)

Phase-shift keying

Phase-shift keying (PSK) is a digital modulation process which conveys data by changing (modulating) the phase of a constant frequency carrier wave. The modulation is accomplished by varying the sine and cosine inputs at a precise time. It is widely used for wireless LANs, RFID and Bluetooth communication. Any digital modulation scheme uses a finite number of distinct signals to represent digital data. PSK uses a finite number of phases, each assigned a unique pattern of binary digits.

Multivibrator

A multivibrator is an electronic circuit used to implement a variety of simple two-state devices such as relaxation oscillators, timers, latches and flip-flops. The first multivibrator circuit, the astable multivibrator oscillator, was invented by Henri Abraham and Eugene Bloch during World War I. It consisted of two vacuum tube amplifiers cross-coupled by a resistor-capacitor network. They called their circuit a "multivibrator" because its output waveform was rich in harmonics.

Two-dimensional nuclear magnetic resonance spectroscopy

Two-dimensional nuclear magnetic resonance spectroscopy (2D NMR) is a set of nuclear magnetic resonance spectroscopy (NMR) methods which give data plotted in a space defined by two frequency axes rather than one. Types of 2D NMR include correlation spectroscopy (COSY), J-spectroscopy, exchange spectroscopy (EXSY), and nuclear Overhauser effect spectroscopy (NOESY). Two-dimensional NMR spectra provide more information about a molecule than one-dimensional NMR spectra and are especially useful in determining the structure of a molecule, particularly for molecules that are too complicated to work with using one-dimensional NMR.

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A simple approach to single-channel quadrature detection

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