Connector Data; Typical Operating Considerations - ORTEC 419 Operating And Service Manual

INT./EXT. (REFERENCE VOLTAGE) — The
INT./EXT. reference voltage switch allows an
external reference voltage to be supplied to the
mercury relay through the PULSE HEIGHT control.
The external reference voltage is supplied through
the BNC connector on the rear panel. Any arbitrary
voltage can be applied to the external BNC
connector, but the maximum voltage should not
exceed 20 V (refer to Section 3.3). The POLARITY
and NORMALIZE controls have no effect on the
output pulse when the switch is set to EXT.

4.2. CONNECTOR DATA

CN1 (DIRECT OUTPUT BNC CONNECTOR) —
This is a dc-coupled, unattenuated output which
looks back directly at the wiper of the relay and has
an output impedance of 100
connector provides a constant output voltage for a
given setting of the PULSE HEIGHT control
independent of the position of the RISETIME and
ATTENUATION FACTOR switches. Output voltage
range is from 0 to 1 V maximum into 100
direct output may or may not be terminated with a
100- terminator. If the output is terminated with a
S
100- terminator, the decay time of the output
S
pulse will change from a nominal value of 400
a value of 200 s . The polarity of the Direct Output
:
pulse will be either positive (+) or negative (-) as
determined by the POLARITY switch.
C N 2 ( A T T E N U A T E D
CONNECTOR) — The attenuated output is a dc-
coupled output connector with an output impedance
of 100 . The attenuated output has in series with
S
it the ATTENUATION FACTOR switches and the
RISETIME control switch. The use of these
switches therefore alters the pulse shape appearing
at the attenuated output for a given setting of the
PULSE HEIGHT control. The attenuated output
should always be terminated with 100
polarity of the output pulse will be either (+) or (-) as
determined by the POLARITY switch.
CN3 (EXT. REF. BNC CONNECTOR) — The BNC
connector on the rear panel provides for the use of
an external reference voltage into the 419. The
external reference voltage may be any arbitrary
waveshape, either dc or a time varying function
such as a linear ramp (refer to Section 3.3).
TPI (DIRECT OUTPUT
Oscilloscope test point for monitoring signal on the
. The output of this
S
. The
S
s to
:
O U T P U T B N C
. The
S
TEST POINT) —
5
DIRECT OUTPUT BNC Connector, CN1. This test
point has a 470-
S
CN1.
TP2 (ATTENUATED OUTPUT TEST POINT) —
Oscilloscope test point for monitoring signal on
ATTENUATED OUTPUT BNC Connector, CN2.
This test point has a 470-
connecting it to CN2.
TP3 — Ground test point used in conjunction with
TP4.
TP4 — The voltage between TP4 and TP3 is the dc
voltage selected
potentiometer on the front panel. These test points
provide a convenient location for continuous
monitoring of the reference voltage supplied to the
relay and pulse-forming network.
POWER CONNECTOR — Nuclear standard
instrument module power connector.
4.3. TYPICAL OPERATING
CONSIDERATIONS
VOLTAGE AND CHARGE TERMINATORS
CHARGE TERMINATION
which consists of a 100-
series capacitor is supplied for use with charge-
sensitive preamplifiers such as the ORTEC 109A.
When this terminator is used, the maximum output
pulse is 1 V or 2 pC (44 MeV for silicon diode
detectors). When using the charge terminator to
drive charge-sensitive preamplifiers, a coaxial
cable having an impedance of approximately 100
(RG-62/U) should be used between the pulse
generator and the
terminator should be located at the input connector
of the preamplifier. The charge terminator may be
used with or without a detector connected to the
input of a preamplifier. If a detector is connected to
the preamplifier, detector bias must be applied to
reduce the effective detector capacity shunting the
charge-sensitive preamplifier input. Also, with the
charge terminator used simultaneously with a
semiconductor detector, the charge terminator
effectively shunts the detector with approximately
2.5 pF of shunt capacity, which will correspondingly
degrade the signal-to-noise performance of the
preamplifier.
series resistor connecting it to
series resistor
S
by the PULSE HEIGHT
A charge terminator
shunt resistor with a 2-pF
S
charge terminator.
S
The