It seems a number of NMR labs like to stick a digital oscilloscope
online (so to speak) by using a line section/plug-in element (from Bird
Electronic Corp. USA, for exmaple) sitting in the transmitter line. My
understanding is that this component picks up the reflected power from
the probe and thereby visualise the input pulses and waveforms on the
scope, giving a realtime check on what the pulse programmer is
producing. I understand the line section/plug-in element hardly affects
the RF power at all.
I have seen this in operation in a couple of laboratories - it is really
a nice thing to have to confirm that the pulse program is really doing
the right thing - but it's not a cheap thing to do if you don't have a
high frequency digital scope (eg. 500MHz or 1GHz). Can it be done less
expensively if all you want to visualise is the presence or absence of a
pulse rather than the high frequency oscillations within the pulse? What
I have in mind (and this may be the mad part) is that you could
integrate or rectify the input to a (lower frequency) scope and thereby
simply observe the pulse envelope? If so, what sort of device could be
to achieve this the integration step? I am obviously looking for an
off-the-shelf component or (very) simple homemade device design.
If this is a stupid idea, please let me know. We are hoping to get a
high frequency scope soon, but we feel we need a stop-gap solution.
Any help/advice with this idea would be appreciated. I am looking to get
more involved with issues of this kind. If there is any more general
advice which books/magazines to consult for NMR/RF/elctronics ideas
coulkd you let me know.
Cheers,
Paul
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Paul Driscoll | Office (answer)phone: (44)-171 380 7035
Dept. Biochem. & Mol. Biol. | NMR lab phone: (44)-171 391 1354
University College London | driscoll@biochem.ucl.ac.uk