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