Service manual

5
2. SPECIFICATIONS
2.1. PERFORMANCE
INPUT SIGNAL AMPLITUDE RANGE ±1.0 V ac,
±5.0 V ac with X5 internal Attenuator; ±35 V dc;
input impedance 100
; 50 optional.
OUTPUT AMPLITUDE RANGE 0 to ±5 V linear
into a 50
load.
RISE TIME <5 ns with Integrate and Differentiate
Out, or
2.2
i
for other integrate settings and
Differentiate Out.
OVERSHOOT Typically 10% with Integrate Out, or
<2% for any selected integration.
NOISE For maximum gain, rms noise referred to
the input is <10
V (typically 5 V), with
i
=
D
) =
200 ns, measured with an HP3400A true rms
voltmeter. Wideband (200 MHZ) noise for
i
=
D
=
Out is <50
V (typically 40 V).
INTEGRAL NONLINEARITY <1% (typically 0.5%)
over ±5 V range into 50
load.
TEMPERATURE INSTABILITY DC level <±50
V/°C referred to the output. DC level factory-set to
±5 mV. Gain instability <0.05%/°C (Figs. 1.5 and
1.6).
OPERATING TEMPERATURE RANGE 0°C to
50°C (273 to 323 K).
2.2. CONTROLS AND INDICATOR
COARSE GAIN Front panel 6-position switch to
select X15, X25, X50, X125, X250, and X500 gain
factor. When internal X5 Attenuator is used, the
coarse gain factors represent X3, X5, X10, X25,
X50, and X100 respectively. A continuously variable
voltage gain of X0.9 to X500 can be obtained. (Gain
reduced by factor of two when cable clip is used.)
FINE GAIN Front panel single-turn potentiometer,
continuously adjustable from 0.3 to 1.0.
P/Z Front panel screwdriver adjustable
potentiometer to adjust pole-zero cancellation for
decay time constants from 25
s to .
DIFF Front panel 7-position switch selects a
differentiation time constant to control the decay
time of the pulse. Decay time
2.2
D
with
i
= Out.
The
D
settings include Out, 10, 20, 50, 100, 200,
and 500 ns.
INT Front panel 7-position switch selects an
integration time constant to control the rise time of
the output pulse. The rise time is
2.2
i
with
D
=
Out. The
i
settings include Out, 10, 20, 50,100,
200, and 500 ns. Rise time in the Out position is <5
ns, equivalent to a
i
<2.3 ns.
INV/NONINV Front panel locking toggle switch
selects inversion or noninversion of the input signal.
BLR ADJ Front panel screwdriver adjustment to set
the Gated BLR threshold from ±50 mV to ±500 mV
referred to the output.
BLR GATED/UNGATED PCB jumper select for
gated or ungated BLR operation. Factory-set in
gated position.
BLR LED This feature enables the user to quickly
adjust the BLR threshold setting near the noise
peak. Front panel LED indicates an output
amplitude has exceeded the BLR threshold. The
BLR LED can be used as a visual indicator of the
output count rate.
COUNT RATE
High/Low PCB jumper selects minimum BLR
deadtime of typically 400 ns in high position and
typically 1
s in low position. Factory-set in low
position.
ATTENUATOR PCB jumper select to pass with
unity Gain or Attenuate by a factor of 5. Jumper
select B to C and A to F will pass with unity Gain.
Jumper select C to D and E to F will attenuate by a
factor of 5. Factory-set at unity Gain.
2.3. INPUTS
INPUT Front panel BNC accepts input signals of
either polarity, ±1.0 V ac or ±5.0 V ac with X5