Ametek ORTEC digiBASE, Руководство пользователя

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digiBASE
®
PMT Base with Integrated Bias Supply, Preamplifier and Digital Multichannel Analyzer 931003E / 0620
3.1.1. Inputs
ENABLE INPUT
The SMA connector accepts a TTL signal, the function of which depends on
the Gate setting on the ADC tab under Acquire/MCB Properties... in MAESTRO.
!
When set to
Enable
, if the ENABLE INPUT is low (<0.8V), real time, live time, and data
acquisition are stopped. When the ENABLE INPUT is left open or forced high (>2.0V),
real time, live time, and data acquisition is enabled.
!
If set to Coincidence , when the ENABLE INPUT is low, real time and live time operate
normally, but no counts are stored in memory. If the ENABLE INPUT is high, normal
acquisition occurs.
!
If set to Event , rising edges are counted by a 32-bit event counter. The contents of the
counter can be monitored on the Status tab under Acquire/MCB Properties... in
MAESTRO. Input impedance is 5 k Ù to +3.3V, protected to ±10 V.
USB Full-speed (12M bps), bus-powered USB 1.1 interface.
3.1.2. Special Performance Features
List Mode Acquisition If you need the ultimate in fine time resolution — especially important
for Homeland Security applications — the digiBASE features List Mode operation, in which
each valid input signal is converted to a digital value, which is transmitted to the computer along
with the time the event occurred. Time is measured to the nearest microsecond. Each event
causes a 32-bit word to be transmitted to the computer. The bits of the word are decoded as
follows:
Bit Description
31 (msb) TimeStampFlag (0 = Normal Data, 1 = Time Stamp)
30–21 Amplitude of the event
20–0 Time event arrived in units of microseconds
In addition, every second a “time stamp” word is transmitted. This time-stamp word is used to
track rollovers in the 21-bit time stamp in the normal data word.
Bit Description
31 (msb) TimeStampFlag (0 = Normal Data, 1 = Time Stamp)
30–0 Current time in microseconds
20