NM20216A-F
21
Technical data
1
• The units can be operated either in a mirroring mode duplicating the
input/output at two physically separate places (16 lines total, default
mode) or independently (32 lines total, optional)
• Each channel individually selectable as input or output
• Internal trigger line generation to 16 lines
• The trigger lines are optically isolated and synchronized to the MEG/
EEG sampling
Stimulus input:
• Input pulse level: TTL (+ 5 V high, 0 V low), trigger on rising or falling
edge (each channel individually user-configurable).
• Each input has a user-selectable pull-up for connection of passive
switches
• Minimum input pulse width: 10
µ
s
• Absolute maximum ratings for input voltage: –0.5 V…+5.5 V
• Input impedance: 1 M
Ω
(without pull-up)
• Pull-up loop current 500
µ
A
• Input mode: single-ended. Optically isolated from main electronics.
• Delay from interface unit to trigger acquisition less than 50
µ
s
• Minimum detectable pulse length 50
µ
s
Stimulus output:
• Pulse level: TTL (+ 5 V high, 0 V low), rising or falling edge (each
channel individually user-configurable)
• Pulse width: typ. 10 ms
• Pulse rate: adjustable from data acquisition program
• Maximum output current: 25 mA
• Output mode: single-ended. Optically isolated from main electronics
• Delay from trigger generation to interface unit less than 50
µ
s
• Pulse length determined in acquisition program (minimum 1 ms)
Input power:
• +8…12 V
=
, 100 mA. Double-insulated separate supply.
1.8.
Computer system hardware
• Continuous acquisition time: over 1 hour with 306 MEG and 64 EEG
channels sampled at 3 kHz.
• Computers: H-P’s PA-RISC UNIX workstations with two monitors
• Removable magneto-optical disk (option)
