tag:blogger.com,1999:blog-3300702123878659843.post7858228626862891140..comments2024-03-26T05:25:50.831-04:00Comments on University of Ottawa NMR Facility Blog: What Does an RF Pulse Actually Look Like?Glenn Faceyhttp://www.blogger.com/profile/05146575170575279335noreply@blogger.comBlogger6125tag:blogger.com,1999:blog-3300702123878659843.post-22607140666046958222010-04-16T10:36:27.681-04:002010-04-16T10:36:27.681-04:00Anonymous,
Thank you for your comment. To answer...Anonymous,<br /><br />Thank you for your comment. To answer your questions....<br /><br />1. Radio frequency pulses are monochromatic but since they have finite width, a Fourier analysis of the pulse contains many frequencies. In very simplistic terms, the Fourier transform of the pulse determines its excitation profile.<br /><br />2. and 3. See this post:<br />http://u-of-o-nmr-facility.blogspot.com/2009/12/defining-excitation-profile.html<br /><br />GlennGlenn Faceyhttps://www.blogger.com/profile/05146575170575279335noreply@blogger.comtag:blogger.com,1999:blog-3300702123878659843.post-88454831414752548572010-04-16T05:10:07.117-04:002010-04-16T05:10:07.117-04:00Thank you very much Glenn.
But now I've more d...Thank you very much Glenn.<br />But now I've more doubts. Please help me if time permits.<br />1. How many radio-frequencies are there in a pulse? (is a pulse monochromatic?)<br />2. If the pulse is monochromatic, how is it able to (quantitatively) excite nuclei of different chemical equivalence?<br />3. If the pulse contains many radio-frequencies, what is the range over which it does quantitative excitation?<br /><br />Thanks and regards<br />VinodAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-3300702123878659843.post-9945256797922676662010-03-15T09:21:57.627-04:002010-03-15T09:21:57.627-04:00Dear Anonymous,
1. The phase of the pulse is def...Dear Anonymous,<br /><br />1. The phase of the pulse is defined in the pulse program, usually in a phase list. In the case of Bruker pulse programs; 0=x, 1=y, 2=-x and 3=-y.<br /><br />2. I am not sure what coil shape you refer to. The pulses are delivered to the sample via the coil in which the sample sits. The simplest configuration is a horizontal solenoid coil in a vertical superconducting magnet. During the application of the pulse, the sample experiences an oscillating transverse magnetic field. This is also true for a vertically oriented Helmholtz coil. See the BLOG entry for March 17, 2008. http://u-of-o-nmr-facility.blogspot.com/2008/03/probe-coil-geometry.html.<br /><br />GlennGlenn Faceyhttps://www.blogger.com/profile/05146575170575279335noreply@blogger.comtag:blogger.com,1999:blog-3300702123878659843.post-30910393083363357422010-03-12T08:04:28.061-05:002010-03-12T08:04:28.061-05:00Hi Glenn,
Thank you very much for this wonderful b...Hi Glenn,<br />Thank you very much for this wonderful blog.<br />I have two doubts. Please help me if you find some time.<br />1. How is the phase of a RF pulse defined?<br />2. How is it applied in RF to the sample, from this coil-shape?<br />Thanks and Regards<br />VinodAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-3300702123878659843.post-23721716568674551992010-01-14T15:50:46.594-05:002010-01-14T15:50:46.594-05:00Magdalena,
I have never observed that , so cannot...Magdalena,<br /><br />I have never observed that , so cannot say.<br /><br />GlennGlenn Faceyhttps://www.blogger.com/profile/05146575170575279335noreply@blogger.comtag:blogger.com,1999:blog-3300702123878659843.post-35145318822055066412010-01-14T12:17:45.166-05:002010-01-14T12:17:45.166-05:00Hi,
How does coil affect the RF pulse shape?
Whe...Hi,<br /><br />How does coil affect the RF pulse shape?<br /><br />When measuring the reflected signal of the sample with an oscilloscope, why are there high spikes on edges? <br /><br />Your blog is very helpful.<br /><br />MagdalenaMagdalenanoreply@blogger.com