Filter
Top Products
Using the Digital to Analog Converter (DAC)
2–52
VX4101A MultiPaq Instrument User Manual
Using the Sample Handshake Mechanism
The handshake mechanism is similar to external trigger except that it adds a
second signal to notify the unit under test that the instrument is ready to accept
the next trigger. The handshake trigger input is called DAC. A second signal
DAC, provides a signal back to the user indicating the DAC is ready for the next
trigger. The default polarity of both DAC and DAC are active low.
The following example demonstrates the handshake mechanism in sequence
mode. Segment and sample modes are similar. In this example, a burst of
10 triangle waves will be triggered by a square wave signal generator. The
triangle waves have a period of 4 milliseconds. The burst will have a duration of
40 milliseconds. The trigger source will be a TTL square wave with a period of
10 milliseconds (the trigger source simulates a trigger that may have a period
shorter than the programmed sequence).
To ensure the trigger is not re-initiated during the burst, the square wave
generator must be qualified by the DAC’s Analog Output Request signal. To
accomplish this, do the following:
1. Connect the DAC as described above to a 100 Hz TTL signal generator.
2. Reset to the default settings:
*RST
Perform the following steps:
1. Place an R/S flip flop between the square wave trigger source and the DAC.
a. Connect the flip-flop S input to the square wave signal source.
b. The Q* output is connected to the DAC’s Analog Output Request.
c. The flip-flop Clear* input is connected to the DAC’s Analog Output
Strobe.
d. The R input is connected to ground
2. Select the DAC as the active instrument:
INST:SEL DAC
3. Program the internal sample rate to 10 kHz:
TRAC:SRAT 10000
4. Program the number of sample points to 40:
TRAC:POIN 40
Hardware Tips
Programming Example