EG&G ORTEC 552 Kullanım ve Servis Kılavuzu - Sayfa 9
Ölçüm Cihazları EG&G ORTEC 552 için çevrimiçi göz atın veya pdf Kullanım ve Servis Kılavuzu indirin. EG&G ORTEC 552 16 sayfaları. Pulse-shape analyzer and timing single-channel analyzer
Sayfayı YazdırThe input Impedance of the 552 is lOOOfi. When long
cables are used to connect the amplifier output to the 552
Input, cable termination may be necessary in orderto pre
vent reflections: match the cable impedance with a term
inator at the 552 Input in such cases.
Normally, the ATTN switch on the 552 front panel will be
left at its XI setting for operation in a system. The main
purpose for the X10 and X100 attenuator settings are to
aid in precise walk adjustments.
3.4.
OUTPUT CONNECTIONS
Outputs are furnished through both channel A and
channel B connectors. Each channel is considered sepa
rately because of the differences in timing characteristics
of the two channels. The channel A output on the front
panel is dependent only on satisfaction of the input logic
of the single-channel analyzer and it occurs at the se
lected trigger level on the trailing edge of the linear input.
The channel B outputs are dependent on satisfaction of
input logic and of a strobe, which can be either internally
generated or furnished from an external source.
The channel A output is available as a NIM-standard fast
negative pulse from a front panel BNC connector. It is
intended for transmission to the driven unit through 50n
cable with 50fl termination. When the 552 is set for either
the Normal or Window mode, a channei A output means
that an input pulse amplitude is sufficient to trigger the
lower-level discriminator without also triggering the
upper-levei discriminator. When the 552 is set for the
Integral mode of operation, the channel A output means
that the input pulse amplitude is sufficient to trigger the
lower-level discriminator; triggering of the upper-level
discriminator does not affect the output for this mode.
The time when a channel A output is made available is
promptly at a trigger point on the decay of the input wave
form. The decay level is selected by an internal jumper on
the printed circuit board, which can be set for 10%, 20%, or
50%, referring to the decay from the peak amplitude of
the pulse.
Three channel B outputs are available. A NIM-standard
fast negative pulse is furnished through a front panel con
nector and a NIM-standard slow positive puise is fur
nished through both front and rear panel connectors. The
negative output is intended for transmission to the driven
unit through 50n cable with 50fl termination. The positive
outputs can be furnished through 50n or 93n cable to the
driven unit. A channei B output means that the logic for
the channel A output has been satisfied and that an output
strobe is furnished. The output strobe can be generated
internally or furnished from an external source, depend
ing on the setting of the rear panel switch.
The time when the channel B outputs are generated,
using the internal strobe, is at a fixed delay after the trig
ger point on the decay of the input waveform. The decay
level is selected by a front panel switch that can be set at
any multiple of 10% from 10% through 100% (baseline
crossover of a bipolar input), referring to the decay from
the peak amplitude of the pulse. The range of the front
panel Delay control is about 0.1 through 1.1 fiS. The
channel B output time, using an external strobe, is
promptly at the strobe pulse; this strobe pulse must be
furnished within 10 ns after the trigger point or the in
ternal logic is reset without generating a channel B out
put.
Separate logic outputs are available through the rear
panel to indicate when, on the leading edge of an input
pulse, each of the two discriminators is triggered. These
responses can be used to monitor the discriminator levels
during adjustment, to be counted in external sealers, to
provide subgroup routing to a multichannei analyzer, or
for any other applications desired. Each logic output for
LL Out and UL Out is a NIM-standard slow positive pulse
that is compatible with ORTEC counters, ratemeters, and
other Instruments. The output impedance through each
output path is sufficiently low to drive as many as ten
paralleled lOOOfl inputs.
3.5.
LOWER-LEVEL REFERENCE INPUT
If the LL Ref toggle switch on the rear panel of the 552
is set at Ext, the reference level for the lower-level discrim
inator must be furnished through the adjacent In BNC
connector; the 10-turn Lower-Level control on the front
panel is disconnected. An input of 0 to -10 V through this
connector corresponds directly to a range of 0 to +10 V
for the lower-level discriminator threshold.
The signal through the LL Ref In connector is not used
unless the toggle switch is set at Ext.
4.
OPERATING INSTRUCTIONS
After the 552 has been connected into a system according
to the installation information in Section 3, the operating
and strobe modes can be selected and the discriminator
thresholds can be adjusted as required for each appli
cation.
Figure 4.1 illustrates the timing relationships that will be
effective in the 552, operating with an internal strobe, for
each of three possible input pulse ampitudes. The first
two pulses exceed the lower-level threshold without also
exceeding the upper level, and the third pulse exceeds
both threshold levels. Superimposed on each of these
input pulses in Fig. 4.1 are two internally stretched con
stant-fraction reference levels; the upper stretched level
is at the 50% point on the input pulse decay, which can be
set in channel A; the lower stretched level is at the 70%
point on the input pulse decay, which can be set in
channel B. When the input pulse decays through the 50%
level, the channel A CF discriminator is fired and triggers
a prompt channel A output. When the input pulse decays
through the 70% level, the channel B CF discriminator is
fired and triggers an internal delay, which then generates
both negative and positive channel B outputs at the end of
the delay. The delay is fron^anel adjusted in the range of
0.1 through 1.1 ixs. If the 552 is set for Normal or Window
mode, time-significant pulses would be generated for