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4. OPERATING INSTRUCTIONS
4.1. TIME-TO-AMPLITUDE CONVERSION
There are nine front panel controls on the 567. Of
these, four are directly associated with the
conversion of a start-to-stop interval into an analog
equivalent TAC output pulse. These controls are
Range ns, Multiplier, TAC output Delay, and
Anti/Coinc. If the SCA inhibit switch is set at In, this
also affects the generation of a TAC output.
The Range (ns) and Multiplier switches determine
the full scale limit for time conversion. Any of 15
combinations may be selected as follows:
Switch Settings
Full-Scale
Range (ns) Multiplier Time Limit
50 x1 50 ns
100 x1 100 ns
200 x1 200 ns
50 x10 500 ns
100 x10 1 µs
200 x10 2 µs
50 x100 5 µs
100 x100 10 µs
200 x100 20 µs
50 x1k 50 µs
100 x1k 0.1 ms
200 x1k 0.2 ms
50 x10k 0.5 ms
100 x10k 1 ms
200 x10k 2 ms
For example, with the Range switch set at 50 and
the Multiplier switch at X100, the full-scale time
range is 5 µs. Any stop input signal that occurs
within 5 µs after a true-start signal will initiate the
gating of an output pulse through the Output
connector. The output pulse will not be furnished
through this connector unless it is strobed. The
strobe condition is selected by a front panel switch.
When the output does occur, its peak amplitude will
be proportional to the ratio of the measured start-to-
stop interval to the selected full-scale time in a 0 to
10V range.
Internal logic eliminates any pulse ambiguity. No
output pulse is furnished unless a stop signal is
accepted within the selected full-range time. A stop
signal is not effective unless it is preceded by a
Valid Start signal. For further logical control either
a coincidence or an anticoincidence mode can be
selected for the Start Gate and Stop Gate inputs.
To defeat the Start Gate function, leave the Start
Gate input disconnected and select the
anticoincidence position of the Start Gate Mode
switch. If the start gate signal is applied in the
anticoincidence mode, start pulses will be blocked
during the start gate signal. Anticoincidence gating
will function in the same manner when controlling
the Start or Stop Gate input.
For coincidence gating of the Start or Stop input
circuit set the Start Gate or Stop Gate Mode switch
to Coincidence and furnish an appropriate polarity
gate signal through the Start or Stop Gate input
connector when Start signals are to be accepted.
If a signal is furnished through the Inhibit/Reset
connector on the front panel, any time
measurement that may be in process will be
aborted and no new measurement can begin until
the inhibit/reset signal is removed. To be effective,
the inhibit/reset signal must precede an output
strobe time.
The rear panel Strobe External switch selects the
source for the strobe signal for the TAC output.
When the switch is set at Ext, an input pulse must
be furnished through the adjacent BNC connector
and the TAC output signal is strobed promptly at
the external signal time.
The timing of an external strobe input signal must
be within the switch-selected interval, 10 or 100 µs,
after the true-stop pulse for the measurement. If the
strobe is furnished prior to stop, the signal is not
accepted. In the case of a strobe pulse failing to
arrive within the selected interval after stop, the 567
will have been automatically reset internally, so
there is no available output and the strobe signal is
ignored.
4.2. SINGLE-CHANNEL ANALYZER
The single-channel analyzer (SCA) portion of the
567 measures the peak amplitude of each analog
TAC pulse as soon as it is formed. If the peak
amplitude is within the limits that are set with the
LLD and Window controls on the front panel, an
SCA output signal is generated. The signal can be
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