Chapter4 HardwareOverview
©NationalInstruments Corporation 4-21 NI5102 User Manual
•Analog TriggerCircuit Output—Thi ssig nal is the digital output of
the Analog TriggerCircuit on the NI 5102. The frequency and duty
cycleof this signal depends on the trigger channel, the trigger levels,
polarity,and triggering mode. For more information, see the Analog
Trigger Circuit section earlier in this chapter or your NI-SCOPE
Software User Manual.
•FrequencyOutput —This signal is a digital pulse train with
programmablefrequency. The most common application of frequency
output for the NI 5102 is to provide a signal for compensating the
probe.You can select two timebases to generate this frequency as
follows:
–7.16 MHz (asynchronous to 20 MHz internal timebase)
–1.25 MHz (synchronous to 20 MHz internal timebase)
The NI 5102 uses a 16-bitc ounter to programmatically select
frequencyat the output. The pulse train frequency as a function
oft he counter valuecan be expressed as:
Frequency = timebase/divide_ratio
where divide_ratio= 3 .. 65,535
Alternatively,to compute divide_ratio for a particular frequency,
the relationship is:
divide_ratio = timebase/frequency
Forexample, to generate a 1 kHz pulse train, common for probe
compensation, select the following parameters:
–timebase = 1.25 MHz
–divide_ratio= 1,2 50
•Low—Thisis the TTL low voltage referenced to the ground potential
ofthe computer. This is a signal at logic level low.Do not use this as
GND for your circuit.
•High—Thisis the TTL high voltage referenced to the ground p otential
ofthe co mputer.This is a signal at logic level high. Do not use this as
VCC for your circuit.
Caution Referto the output drive specification of PFI lines in Appendix A, Specifications.
Failureto observe these limits may severely damage your NI 5102.