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The optically Isolated Pulse Stimulator (Model 2100) has been designed for a wide variety of physiological stimulation requirements. A flexible, accurate system, it can be operated free running, manually triggered, or externally triggered. A TRIGGER indicator lights up when an |
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acceptable
trigger event is received. An EVENT indicator lights
up whenever a pulse is delivered. The
operator describes the desired pulse train by setting
four times; the delay time (time between trigger and
the first pulse); train burst width time; individual
pulse duration; and interpulse period (the duration of
a single pulse on/off cycle). lf the period set is shorter than the pulse duration, a timing overlap
error LED indicator warns the user of this condition. For
ease of use, the delay may be set to "none",
so that no extra delay occurs between trigger and
pulse output. The burst width may be set to
"single", so that only a single pulse is
output for a single triggering event. This has the
additional effect of suppressing the post-pulse delay
associated with the inter-pulse period, thus allowing
the stimulator to become immediately retriggerable,
instead of waiting until the end of the period. The
pulse duration may be set to "square",
automatically setting the period to exactly one half
of the period. The
times are easily and rapidly set with leverwheel
switches, which are much more convenient than
thumbwheel switches. The timing accuracy is dependent
only on a 10 MHz internal crystal clock which has an
absolute accuracy of better than 0.02%, and
timer-start jitter of ±250 ns (±2.5 µs in the 100
second range). The full-scale amplitude accuracy is 1%, with a voltage-mode output impedance of less than 100 Ohm, and a current-mode output impedance of at least 1 MOhm . The output pulses may be monophasic (selectable polarity), or biphasic, in which a positive pulse is immediately followed by a negative pulse. The baseline amplitude is independently adjustable, up to ±10% of the pulse amplitude range. |
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