• Continuous waveforms are output by some or all DACx for
the duration of the pattern on state of the pattern
generator. Continuous waveforms ignore pattern periods.
• Periodic pulse trains that repeat indefinitely are waveforms
that are output once during each pattern period. Pattern
periods occur one after the other as long as the pattern
generator is in the pattern on state.
• Periodic pulse trains that repeat a finite number of times
are just like those that repeat indefinitely except that the
waveforms are output during a finite number of
consecutive pattern periods.
Figure 42. Periodic Pulse Trains output on all DACx
PATTERN GENERATOR PROGRAMMING
Figure 44 shows periodic pulse train waveforms as seen at
the output to each of the four DACx. The four waveforms are
generated in each pattern period. Each has its own start delay
(START_DLYx), a delay between the start of each pattern
period and the start of the waveform. The four DACx
waveforms are the same digital signal stored in SRAM and
multiplied by the DACx digital gain factor. The SRAM data
is read using each DACx address counter simultaneously.
Setting Pattern Period
Two register bit fields are used to set the pattern period. The
PAT_PERIOD_BASE field in the PAT_TIMEBASE register sets
the number of CLKP/N clock per PATTERN_PERIOD LSB.
The PATTERN_PERIOD is programmed in the PAT_PERIOD
register. The longest pattern period available is 65535 ×
Setting Waveform Start Delay Base
The waveform start delay base is programmed in the
START_DELAY_BASE field of the PAT_TIMEBASE register.
Each DACx has a START_DLYx register described in
the DACX Input Data Paths section. The start delay base
determines how many CLKP/CLKN clock cycles there are
per START_DELAYx LSB.
tDLY = PATTERN_DELAY VALUE + 1
Figure 43. Trigger Initiated Pattern Start with Pattern Delay
Figure 44. Trigger Rising Edge Initiated Pattern Stop
Figure 45. RUN Bit Driven Pattern Stop
DACx INPUT DATA PATHS
Each of the four DACx has its own digital data path. Timing
in the DACx data paths is governed by the pattern generator.
Each DACx data path includes a waveform selector, a waveform
repeat controller, RAM output and DDS output multiplier
(RAM output can amplitude modulate DDS output), DDSx
cycle counter, DACx digital gain multiplier, and a DACx digital
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