Figure 3-3. Sync Output And Duty Cycle; Sync Connector; Pll Ref Connector - National Instruments DAQArb 5411 User Manual

SYNC Connector

PLL Ref Connector

Note:
© National Instruments Corporation
The SYNC connector is a transistor-transistor-logic (TTL) version of
the sine waveform being generated at the output. You can think of the
SYNC output as a very high frequency resolution,
software-programmable clock source for many applications. You can
also vary the duty cycle of SYNC output on the fly by software control,
as shown in Figure 3-3. t
generated and t
w
is (t /t x 100%.
w p)
ARB Output
SYNC Output
(50% Duty Cycle)
SYNC Output
(33% Duty Cycle)
You can route the SYNC output to the RTSI lines over the RTSI bus.
The SYNC output is derived from a comparator connected to the analog
waveform and is intended to be used when the waveform is a sine
function. The SYNC output will provide a meaningful waveform only
when you are generating a sine wave on the ARB output. For more
information on SYNC output, see Chapter 4, Arb Operation.
The PLL Ref connector is a phase-locked loop (PLL) input connector
that can accept a reference clock from an external source and phase lock
the DAQArb internal clock to this external clock. The reference clock
should not deviate more than ±100 ppm of its nominal frequency. The
minimum amplitude levels of 1 V
lock reference clock frequencies of 1 MHz and 5–20 MHz in 1 MHz
steps.
You can also lock the DAQArb 5411 to other National Instruments cards
over the RTSI bus using the 20 MHz RTSI clock signal.
is the time period of the sine wave being
p
is the pulse width of the SYNC output. The duty cycle
t
p
t
w

Figure 3-3. SYNC Output and Duty Cycle

are required on this clock. You can
pp
3-3
Chapter 3 Signal Connections
DAQArb 5411 User Manual