Continuous Buffered Sample Clocked Pulse Train Generation; Frequency Generation; Using The Frequency Generator - National Instruments DAQ X Series User Manual

Chapter 7 Counters
With non-regeneration, old data will not be repeated. New data must be
continually written to the buffer. If the program does not write new data to
the buffer at a fast enough rate to keep up with the generation, the buffer
will underflow and cause an error.
Continuous Buffered Sample Clocked Pulse Train
Generation
This function generates a continuous train of pulses with variable idle and
active times. Instead of generating a set number of data samples and
stopping, a continuous generation continues until you stop the operation.
Each point you write specifies pulse specifications that are updated with
each sample clock. When a sample clock occurs, the current pulse finishes
generation and the next pulse uses the next sample specifications.

Frequency Generation

You can generate a frequency by using a counter in pulse train generation
mode or by using the frequency generator circuit, as described in the Using
the Frequency Generator section.

Using the Frequency Generator

The frequency generator can output a square wave at many different
frequencies. The frequency generator is independent of the
four general-purpose 32-bit counter/timer modules on X Series devices.
Figure 7-36 shows a block diagram of the frequency generator.
20 MHz Timebase
100 kHz Timebase
The frequency generator generates the Frequency Output signal. The
Frequency Output signal is the Frequency Output Timebase divided by a
number you select from 1 to 16. The Frequency Output Timebase can be
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Frequency
Output
÷
2
Timebase
Frequency Generator
Figure 7-36. Frequency Generator Block Diagram
7-38
FREQ OUT
Divisor
(1–16)
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