Document type: Title: Revision date: Revision:
User's Manual (MUT) Mod. N968 Spectroscopy Amplifier 14/06/2004 4
NPO: Filename: Number of pages: Page:
00100/03:N968x.MUTx/04 N968_REV4.DOC 14 7
2.4 Front panel controls
FINE GAIN: 10-turn precision potentiometer with graduated dial for continuously
variable direct-reading gain factor of x0.5 to x1.5.
COARSE GAIN: 6-position switch, selects feedback resistors for gain factors of 20, 50,
100, 200, 500, and 1k. Two Jumpers on the printed circuit board select
x0.1 attenuation and x2 Amplification (see § 2.5).
S.F. GAIN: SUPERFINE GAIN, screwdriver adjustable potentiometer to adjust fine
gain; adjustment range: ±2.5 % of the FINE GAIN RANGE.
INPUT: Locking toggle switch, selects either Pos (positive) or Neg (negative)
input pulse polarity.
SHAPING TIME: 6-position switch, selects time constants for active pulse-shaping filter
network from 0.5, 1, 2, 3, 6, and 10 µs.
PZ ADJ
1
: Screwdriver adjustable potentiometer to set the pole-zero cancellation
to compensate input decay times from 40 µs to infinity.
DELAY: Locking toggle switch, allows to set UNIpolar output either to prompt or
delayed 2 µs.
BLR: 3-position locking toggle switch, selects the source of control for the
gated baseline restorer discriminator threshold from:
− Auto The BLR threshold is automatically set to an optimum level,
as a function of the signal noise, by an internal circuit.
− PZ Adj Enables the PZ adjustment; the BLR threshold is
determined by the Auto function. The BLR time constant is also
greatly increased to facilitate the PZ adjustment.
− Threshold The BLR threshold is manually set by the threshold
potentiometer in the 0 ÷ 300 mV range.
DC: Screwdriver adjustable potentiometer to set the Unipolar Output DC
level; range ±100 mV.
1
The adjustment must be performed with a low rate input
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