rf filters for triple resonance

Robert D Scott (scott@iastate.edu)
Tue, 03 Oct 1995 12:56:45 CDT

We are just starting down the triple-resonance path and wonder
whether it is better to use notch filters or a combination
of low and high pass filters to keep the channels from talking
to each other? The low/high option seems to offer less attenuation
of the pass band (0.25 dB x 2) to the notch filters 0.8 dB, but you
need to buy twice as many of them and the amps have plenty of power.
The pass band filters would be more selective. Any advice would
be appreciated.

I feel a little guilty about offering our undergrad's 60MHz cw
instruments (em-360's) for their NMR experience. I think that
they like seeing the spectrum of the 'stuff they made' but would
like to introduce them to pulsed nmr, computer processing, and
2d techniques. Our options seem to include either upgrading
the 60's to pulse operation, or putting a large capacity (>100)
auto-sampler on a supercon. The first option would give them real
'hands on' experience with a low maintenance ("green?") magnet.
The second would offer more sophisticated pulse sequences and
allow more time for sample preparation. We're going to demo
an Anasazi upgrade this month to see if it likes hundreds
of students. I think that "hands on" experiences are a good
way to teach (enhances learning) but that the whole point is
to interpret data collected on their sample so could be happy
either way. Unfortunally, both ways cost $$$.

& just to really confuse anyone following threads
While moving machines and offices, we found a box (~10 rolls) of
silent-700 paper which I'll send free to anyone who is still
trying to live with one of those.

dave scott
iowa state university
515-294-4057