The PVA sample was run at 55 degrees centigrade. A 90 degree (6.8us) pulse was used with a inter-pulse delay of 2.1s. Exactly 800 scans were acquired with 16k complex data points and a sweep width of +/-2000 Hz. [Pg.164]

With 2D experiments the situation is a little more complicated as the size of the overall digitised matrix depends on the number of time increments in tl as well as parameters specific to the 2D acquisition mode. Nevertheless, a digitised matrix of TD(2) X TD(1) complex data points is acquired and stored. Similar to ID the effective number o measured data points used for calculation TD(used) and the total number of data points SI to be transformed in t2 and tl may be defined prior to Fourier transformation. These parameters may be inspected and defined in the General parameter setup dialog box accessible via the Process pull-down menu. With 2D WIN-NMR the definitions for TD(2) and TD(1) are the same as for TD with ID WIN-NMR. However, unlike ID WIN-NMR, with 2D WIN-NMR SI(2) and SI(1) define the number of pairs of complex data points, instead of the sum of the number of real and imaginary data points. Therefore the 2D FT command (see below) transforms the acquired data of the current data set into a spectrum consisting of SI data points in both the real and the imaginary part. [Pg.155]

Another option is to use a multiwave technique, whereby the fundamental frequency and several other frequencies (harmonics) are added together into a single complex wave. Each one of these multiwave iterations can be deconvoluted into its components after the test is complete. Thus, each complex data point can... [Pg.1202]

For the continuous-flow measurements, the pseudo-2D spectrum was recorded with a spectral width of 9616 Hz and 64 transients with 8K complex data points, thus resulting in an acquisition time of 0.42 s/transient along the 128 t increments. A relaxation delay of 1.2 s was used and the time resolution... [Pg.239]

dilute solutions (1.5 0.4% w/w) of an equimolar mixture of the secondary references and TMS in the solvents indicated, acquisition time 4 s, spectral width 4 kHz, 32 K complex data points. 6Hexamethyldisilane, (Me3Si)2 we prefer this abbreviation as it eliminates possible ambiguity (HMDS sometimes used for this reference is also used to denote HMDSO). [Pg.228]

The actual Fourier transform is a digital calculation, so not all frequencies are tested. In fact, the number of frequencies tested is exactly equal to the number of time values sampled in the FID. If we start with 16,384 complex data points in our FID (16,384 real data points and 16,384 imaginary data points), we will end up with 16,384 data points in the real spectrum (the imaginary spectrum is discarded). Another difference from the above description is that the actual Fourier transform algorithm used by computers is much more efficient than the tedious process of multiplying test functions, one by one, and calculating the area under the curve of the product function. This fast Fourier transform (FFT) algorithm makes the whole process vastly more efficient and in fact makes Fourier transform NMR possible. [Pg.122]

The spectra were acquired with 2048 t2 complex data points and 256 ri increments in the phase sensitive mode with quadrature detection using the method described by States et al. (25). Water resonance was supressed during the 1.5s relaxation period used in the NOESY, DQF-COSY and TOCSY experiments and the mixing period of the NOESY experiments by irradiating continuously at its resonance frequency. The amide exchange experiments were carried out by... [Pg.618]

zero filling and Fourier... [Pg.134]

Complex data point. A data point consisting of both a real and an imaginary component. The real and imaginary components allowan NMR data set to be phase sensitive, insofar as there can occur a partitioning of the data depicted between the two components. An array of complex data points therefore consists of two arrays of ordinates as a function of the abscissa. [Pg.74]

virtual array transform using a window that can accommodate 2 complex data points can perform an N-point transform (N = 2 ) in the following four steps ... [Pg.80]

© 2019 chempedia.info