Chapter 4
Arb Operation
©
National Instruments Corporation
4-19
DAQArb 5411 User Manual
output. T
d3
is the time between the marker output and Arb output.
T
d4
is the pulse width on marker output. Refer to Appendix A,
Specifications, for more information on these timing parameters.
Figure 4-18.
Waveform, Trigger, and Marker Timings
Note:
You can switch off the analog low-pass filter at any time during waveform
generation.
SYNC Output and Duty Cycle
The SYNC output is a TTL version of the sine waveform being
generated at the output. The signal from the pre-amplifier is sent to a
comparator, where it is compared against a level set by the level DAC.
The output of this comparator is sent to the SYNC connector through a
hysteresis buffer and a 50
Ω
series resistor to provide reverse
termination of reflected pulses.
You can use the SYNC output as a very high frequency resolution,
software-programmable clock source for many applications. You also
can vary the duty cycle of SYNC output, on the fly, by changing the
output of the level DAC. The SYNC output might not carry any meaning
for any other types of waveforms being generated.
Note:
You can change the duty cycle of SYNC output at any time during
waveform generation.
Output Attenuation
Figure 4-19 shows the DAQArb 5411 output attenuator chain. The
output attenuators are made of resistor networks and may be switched
in any combination desired. The maximum attenuation possible on the
DAQArb 5411 is 73 dB.
Trigger Input Signal
(Slope: Positive, TTL)
Waveform Output
(
±
5 V
pp
into 50
Ω
)
Marker Output
(TTL)
T
d1
T
d2
T
d3
T
d4
