Chapter2 HardwareOverview
NI5620 User Manual 2-6 ni.com
acquisition clock in a free-running state, in which the acquisition clock is
notsynchronized toany external reference.
The voltage controlled crystal oscillator (VCXO) is a 64 MHz clock.
The triggerand clock routing area directs clock signals and triggers.
The TIO is the timing engine used for the NI 5620.
The MITE is the PXI businterface. The MITE provides high-speed direct
memory access(D MA) transfersfrom the NI 5620 to the host computer’s
memory.
Other Features
This section contains information on other features on the NI 5620.

Multiple-Record Acquisitions

Afterthe trigger has been received and the posttrigger samples have
been stored,y ou can configure the NI 5620 to begin another acquisition
thatis stored in another memory r ecord on the device.This process is a
multiple-record acquisition. To perform multiple-record acquisitions,
configure the NI 5620 to the number of records to be acquired before
starting theacquisition. The NI 5620 acquires an additional record each
time atrigger is accepted until all the requested records have been stored
in memory. After the initial setup, this process does not require software
intervention.
Betweeneach record, there is a dead time durin g which the trigger is not
accepted.If the record length is greater than 80 µs, this dead time will be
500ns. If, however, the record length is less than 80 µs, the dead time will
be 80 µs. During this time, the memory controller sets up for the next
record.There may also be additional dead time while the mi nimum number
ofp retrigger samples are being acquired. Figure 2-4 shows a timing
diagramo f a multiple-record acquisition.