PicoScope 3000A Series Prog rammer's Guide 83
Copyright © 2011-2013 Pico Technology Limited. All rights reserved. ps3000abpg.en r9
2.12.50
ps3000aSetSigGenArbitrary
PICO_STATUS ps3000aSetSigGenArbitrary
(
short handle,
long offsetVoltage,
unsigned long pkToPk,
unsigned long startDeltaPhase,
unsigned long stopDeltaPhase,
unsigned long deltaPhaseIncrement,
unsigned long dwellCount,
short * arbitraryWaveform,
long arbitraryWaveformSize,
PS3000A_SWEEP_TYPE sweepType,
PS3000A_EXTRA_OPERATIONS operation,
PS3000A_INDEX_MODE indexMode,
unsigned long shots,
unsigned long sweeps,
PS3000A_SIGGEN_TRIG_TYPE triggerType,
PS3000A_SIGGEN_TRIG_SOURCE triggerSource,
short extInThreshold
)
This function programs the signal generator to produce an arbitrary waveform.
The arbitrary waveform generator uses direct digital synthesis (DDS). It maintains a
phase accumulator of phaseAccumulatorSize bits (see parameter table below) that
indicates the present location in the waveform. The top bufferAddressWidth bits of the
counter are used as an index into a buffer containing the arbitrary waveform. The
remaining bits act as the fractional part of the index, enabling high-resolution control of
output frequency and allowing the generation of lower frequencies.
arbitraryWaveform[arbitraryWaveformSize-1]
The generator steps through the waveform by adding a deltaPhase value between 1
and 2
phas eAccumulatorSize
-1 to the phase accumulator every clock period (dacPeriod). If
the deltaPhase is constant, the generator produces a waveform at a constant
frequency that can be calculated as follows:
outputFrequency=
dacFrequency
arbitraryWaveformSize
×
deltaPhase
2
(phaseAccumulatorSize-bufferAddressWidth)
It is also possible to sweep the frequency by continually modifying the deltaPhase. This
is done by setting up a deltaPhaseIncrement that the oscilloscope adds to the
deltaPhase at specified intervals.
To Next Page
Loading...
Need help?
General
