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Dear Andreas and Joachim, there are high-density filter adapters (15 pins) available suitable for your purpose at: http://www.conec.com [log in to unmask] Critical point is the VGA-Signal, if you want to use a display inside the scanner room. To my personal knowledge, there are no filters in the world doing both: filtering sufficient according the industrial specification requirements for scanner shielding and leaving you signal inside strong enough to feed the display. We used 2000 pF for TTL-signals, and 830 pF for VGA-display (without loosing to much of the signal) without apparent artefacts on the images. Michael Russ --------------------------------------------------------------------- Michael O. Russ Klinischer Neuropsychologe GNP Klinikum der J.W. Goethe-Universitaet Klinik f|r Neurologie / ZNN Schleusenweg 2-16 Telefon: (069) 6301-5768 E-mail: [log in to unmask] -----Urspr|ngliche Nachricht----- Von: "Peter Erhard" <[log in to unmask]> An: "andreas joachim bartsch" <[log in to unmask]> Cc: "SPM mailbase" <[log in to unmask]> Gesendet: Freitag, 4. August 2000 11:33 Betreff: Re: cable shielding > Dear Andreas, > > the only way to run a cable into the scanner room is via a > filter plate, that usually consists of low-pass filters. > Any cable going into the scanner room on other routes, > including through the wave-guide, will introducd HF-noise > from outside. This will cause artifacts in your images or > spctra (consider the MR signal in the range of micro-volts). > Usually the scanner should have a few > spare filters. This was not the case for our scanner, where > we constructed a RF-tight insert for the wave guide, that > included an array of double-T filters. However, if you filter > your trigger signal to much, the slope might be too low to do > the trigger-job. Both, the hot line and the ground need to be > filtered. > Another way is to place an LED on the window(outside) and a > photodiode (inside). > > Hope it helps, > Peter > > > On Thu, 3 Aug 2000, andreas joachim > bartsch wrote: > > > Dear group members, > > I am bothered by a hf-artifact due to a trigger cable running into the > > scanner room. Any advice how to eliminate this, e.g. by what means of > > shielding? > > TIA- > > andreas > > > > ----------------------------------------- > > Peter Erhard, Ph.D. > Nuklearmedizinische Klinik und Poliklinik > Klinikum rechts der Isar > Technische Universitaet Muenchen > Ismaninger Strasse 22 > 81675 Muenchen > Germany > > Tel: 49-89-4140 4570 > Fax: 49-89-4140 4938 > [log in to unmask] > > Laura, Marie & Peter Erhard > Josef-Dosch-Strasse 12 > 82131 Gauting > Germany > > Tel: 49-89-8930 9424 > > > %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%