National Instruments 321645c-01 用户手册

下载
页码 554
NI-DAQ FRM for PC Compatibles)
G-12
©
 National Instruments Corporation
Glossary
SS
simultaneous sampling—a property of a system in which each input or 
output channel is digitized or updated at the same instant
S/s
samples per second
STC
system timing controller
switchless device
devices that do not require dip switches or jumpers to configure resources 
on the devices—also called Plug and Play devices
synchronous
(1) hardware—a property of an event that is synchronized to a reference 
clock (2) software—a property of a function that begins an operation and 
returns only when the operation is complete
T
TC
terminal count
T/H
track-and-hold—a circuit that tracks an analog voltage and holds the value 
on command
transfer rate
the rate, measured in bytes/s, at which data is moved from source to 
destination after software initialization and set up operations; the maximum 
rate at which the hardware can operate
trigger
any event that causes or starts some form of data capture
TTL
transistor-transistor logic
U
UI
update interval
unipolar
a signal range that is always positive (for example, 0 to +10 V)
update
the output equivalent of a scan. One or more analog or digital output 
samples. Typically, the number of output samples in an update is equal to 
the number of channels in the output group. For example, one pulse from 
the update clock produces one update which sends one new sample to every 
analog output channel in the group. 
update rate
the number of output updates per second