Showing papers on "Decoupling (electronics) published in 1968"

Natural-abundance c13 nuclear magnetic resonance spectra of medium-molecular-weight organic compounds

Abstract: The difficulties in detection of C13 magnetic resonance signals in organic compounds which arise from the low natural abundance and the small magnetic moment of C13 are well known [1]. For complex substances of biochemical interest, further reduction in signal-to-noise ratio occurs because of extensive carbon-proton spin-spin interactions. Considerable relief from these difficulties is possible in principle with complete proton decoupling that enhances the signals by removing the proton splittings and contributing a favorable Overhauser effect [2]. The problem with proton decoupling as ordinarily practiced is the necessity for extensive variations in the decoupling frequency to locate the proper values for sharp decoupling of all of the carbon resonances. If the C13 signals are already so weak as to require enhancement by time averaging with repetitive scans [3], excessively long scanning times may be necessary to obtain satisfactory spectra. Some idea of what is involved, in a rather favorable case, may be seen from Figure 1, which shows a series of C13 spectra of a mixture of α- and β-pinenes run with four different proton decoupling frequencies with the use of the DFS spectrometer previously described [3,4]. Although the power input at the decoupling frequencies chosen was close to the maximum that could be supplied to the oscillator coil, no one frequency gave sharp proton decouplings for all the carbons. Furthermore, if the intensities of the resonances are to be maximized, quite fine adjustments of the decoupling frequencies are required; this may well lead to prohibitive scanning times. Much more general proton decoupling can be achieved with noise modulation of an average proton frequency with a random-noise generator [5], and this technique has now been found to be highly useful for C13 spectra. The hookup is shown in Figure 2, and sample noise-decoupled spectra for the same pinene sample used to obtain Figure 1 are given in Figure 3. It will be seen that spectral quality is relatively independent of the center-band frequency.

Process for making semiconductor bodies having power connections internal thereto

Abstract: A PROCESS FOR MAKING SEMICONDUCTOR BODIES, SAID BODIES HAVING POWER CONNECTIONS AND DECOUPLING MEANS INTERNAL THERETO, SAID CONNECTIONS CONPRISING DIFFUSED LOW RESISTANCE SEMICONDUCTOR REGIONS, WHEREIN SAID PROCESS COMPRISES THE STEPS OF FORMING THE LOW RESISTANCE REGIONS AND THE DECOUPLING MEANS BY A SERIES OF DIFFUSIONS INCLUDING CONTROLLED OUT-DIFFUSIONS.

General theorem on symmetry-imposed decoupling of ports of a waveguide junction

Abstract: A general theorem concerning the decoupling of ports of a waveguide junction imposed by reflection symmetry is stated and proved. Several examples are given of the use of this theorem to determine, by inspection, that certain ports of specific waveguide junctions must be decoupled because of the symmetry of the junction.

Design of a high-frequency notch filter

Abstract: Design equations for a high-frequency notch filter are presented. The filter makes use of a hybrid coil for decoupling input from output. The notch is obtained from a bridge-type balance, and can be made quite narrow.

Application of Mark III - SOC to Multivariable Control Problems. Part I. High-Gain Decoupling Control Applied to the Longitudinal Axis of the XV-4B VTOL Aircraft.

Abstract: : This document describes synthesis technique for designing a high-gain decoupling controller for direct-lift control of the longitudinal axis of the XV-4B VTOL aircraft. The technique produces a control system which reduces pilot workload during the critical hover and transition modes of flight. The control system can be modified to accommodate a variety of feedback signals, is insensitive to vehicle parameter variations, and requires measurement only of those responses which are to be decoupled. An application of the synthesis technique to a control system employing MARK III Probability State Variable (PSV) devices is described. (Author)

An analysis of the static and dynamic characteristics of a decoupled landing entry vehicle

Abstract: Analysis of static and dynamic characteristics of entry vehicle using decoupled landing concept

Transient Voltage Decoupling Elements

Abstract: Premature and inexact timing of thyratron generators may occur during parallel operation of capacitor discharge circuits. Voltage transients which enter the trigger circuits can be eliminated by decoupling spark gaps. A simple, two electrode, spark gap with corona illumination is described. The low jitter of this gap allows its insertion in the output line of a 15 kV thyratron generator without changing the output performance of the generator.