1. Description of the Hardware
The
Lih 1600
is a high resolution, low-noise scientific data acquisition
system. It utilizes the newest fiber optic and digital signal processing tech-
nologies, in addition to many of the exceptional features of its predecessor
the
ITC-16
. The
Lih 1600
provides expandability and versatility that will
satisfy both current and future needs.
The
Lih 1600
system comprises of a PCI computer interface card and one
or two analog rack units connected by the fiber optic data cables. The fiber
optics provide superb optical isolation, virtually eliminating ground loops,
while increasing the distance between the computer and the recording set-
up to at least five meters. Fiber optic cables are small, flexible, and, unlike
conventional electrical cables do not emit Electro-magnetic radiation.
The
Lih 1600
rack unit has eight analog inputs, four analog outputs, six-
teen digital inputs and sixteen digital output channels all sampling syn-
chronously.
In addition, two 12-bit asynchronous “telegraphing” ADC
channels are available for monitoring slow changing parameters.
The eight analog input channels are separated into two banks of four. Each
bank is multiplexed into one 16-bit 200 kHz A/D converter. Both A/D con-
verters sample simultaneously and synchronously at the maximum conver-
sion rate resulting in a total throughput of 400 kHz. This unique arrange-
ment allows pairs of channels to be digitized without phase-shift. If the
bandwidth of the experiment calls for lower sampling rates, the DSP (dig-
ital signal processor) decimates and/or filters the data. An added benefit
of filtering is the reduction of noise.
The PCI Bus mastering host interface card supports one or two
Lih 1600
rack units. If two rack units are used, then all input and output channels are
doubled and fully synchronized. For systems requiring even more channels,
multiple PCI and
Lih 1600
units are used. Multiple PCI cards installed
in the same or in separate computers can be synchronized.
