U1050A Datasheet, PDF (3/6 Pages) Keysight Technologies – Acqiris Time-to-Digital Converter

Multichannel High-Resolution Time Measurement
The Agilent Acqiris U1050A time-to-digital converters (TDC)
are designed specifically for use in large scale experi-
ments including particle accelerator timing, nuclear fusion
studies, and explosive testing. They are also well suited for
use in commercial instrumentation including time-of-flight
measurement in mass spectrometry and 3D geological
mapping. While the TC840 is a good solution for timing
measurements with accuracy requirements in the range
of 100 ps, the TC842 is available for applications requiring
higher precision.
On-Board Timing Calculation with Fast Data
Readout
With the TC840, timing information for start and stop
events on all channel inputs is obtained by combining a
coarse-grain (5 ns), wide-range (32 bits), real-time count.
This count has a finer grain interpolated result coming
from the analysis of a ramp signal started by the event.
The TC842, with its very high resolution of 5 ps, uses a
sinewave signal that is generated, sampled, and precisely
interpolated at the start of every hit on all the input
channels.
The U1050A can be viewed as a free-running high-resolu-
tion (5 ps or 50 ps) counter with each individual channel
capable of recording the time of arrival of trigger signals
and storing this data in the local memory. The time base
consists of a low phase noise PLL with very low jitter (< 3
ps rms) and a stable, high-accuracy 10 MHz reference. This
time base can also be referenced to an external
10 MHz source through an auxiliary input.
The U1050A is a single- or multistart, single stop TDC. It
has thirteen identical hardware channels, one common
start channel and twelve independent stop channels. The
timing information on the twelve independent channels is
measured relative to the one common start channel.
Start
Stop
Single Start - Single Stop
Each channel consists of:
• A programmable comparator
• An XOR gate used to select the active slope
• A stable signal generator
• An analog-to-digital converter (ADC).
Once digitized, the data is fed to a Xilinx Virtex-2 Pro FPGA-
based data processing unit for storage and readout. Data
readout is achieved with fast direct memory access (DMA)
at up to 100 MB/s.
Each channel is processed to determine the real time of
each detected event, start and stop. The final relative time
value is obtained by subtracting the start time from each
stop time. The internal memory buffer on the card allows
recording of 512 events for the TC840 and 128 events for
the TC842. An auxiliary input for a common veto signal can
be used to enable or disable all start and stop detection, as
desired.
Figure 1. Single acquisition, common start, single stop
Start
Stop
Multistart - Single Stop
Self Calibration
To achieve the desired precision on all the input channels,
the U1050A time-to-digital converter has a powerful self
calibration routine. This self calibration is done simply
through a software command available in the driver, so no
extra programming is needed.
Figure 2. Multi acquisition, common start, single stop
Easy Integration
Agilent Acqiris time-to-digital converters are supplied with
software drivers for Windows^® and Linux, and application
code examples for MATLAB^®, C/C++, Visual Basic, and
LabVIEW. These code examples provide card set up and
basic acquisition functionality, and are easily modified, so
that the card can quickly be integrated into a measurement
system. The flexibility of the driver means that, with mini-
mum software adjustments, any Agilent Acqiris TDC can be
swapped out, replaced, and upgraded over time, with the
latest Agilent Acqiris time-to-digital converter.
Windows is a U.S. registered trademark of Microsoft Corporation.
MATLAB is a U.S. registered trademark of The Math Works, Inc
LabVIEW is a product of National Instruments
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