Sequoia / Tahoe Series User Manual California Instruments
244 M447352-01 REV-A
6. Waveform Management
The Sequoia/Tahoe Series power source incorporates an arbitrary waveform generator that allows the
user to create custom waveforms (up to 50) and download them into the memory of the unit. In addition,
three standard waveforms are always available: sine wave, square wave, and clipped-sine wave. The full
capability of waveform management could be programmed through the remote digital interface using SCPI
commands or the Sequoia Virtual Panels GUI; refer to the Sequoia Series Programming Manual P/N
M447353-01 and Tahoe Series Programming Manual P/N M447354-01 in the AMETEK PPD website,
www.programmablepower.com, to download latest version.
6.1 Standard Waveforms
For many AC applications, the sine wave is the prevalent waveform that is used. Therefore, it is one of the
standard waveforms provided in the power supply and is the default waveform at power-on. In addition to
the sine wave, two more standard waveforms are available, square wave and clipped-sine wave.
The square wave provides fast rise and fall times, with high harmonic content. Due to the power stage
amplifier bandwidth limitations, the frequency content of the standard square wave is restricted to be within
the capabilities of the amplifier. As the fundamental frequency is increased, the relative contribution of
higher harmonics is reduced.
The clipped-sine wave may be used to simulate voltage distortion levels to the unit under test. The total
harmonic distortion level may be programmed in percent using the CLIP % THD field of the WAVEFORMS
menu of the CONFIGURATION screen; Changing the distortion level of the waveform through the display
menu forces the power source to regenerate the data points of the clipped-sine wave, and reload the
waveform register with the newly requested data; this process requires the output to be programmed to
zero. To avoid interrupting the output voltage to the unit under test, SCPI commands could be used through
the digital interface to select a different waveform such as the standard sine wave first, change the CLIP
LEVEL, and then change the waveform back to the clipped-sine wave.
6.2 Creating Custom Waveforms
The Sequoia/Tahoe Series power source provides a library of four waveform groups (numbered 0 through
3), each containing 50 custom-defined waveforms for a total of 200 waveforms, in addition to the three
standard waveforms. Of these four groups, only one could be active at a time. With front panel control,
only the waveform group that was present at the power-on could be accessed. The available waveforms
could be selected through the WAVEFORMS menu of the CONFIGURATION screen.
Custom waveforms cannot be created or deleted from the front panel of the power source. Instead, this
must be accomplished through the remote digital interface. The standard waveforms permanently reside
in memory and could not be deleted. A Windows-based graphical user interface program, Virtual Panels,
is included with the power source that allows waveforms to be created and downloaded easily. Virtual
Panels GUI allows waveforms to be created by specifying harmonic amplitudes and phase angles with
respect to the fundamentals. It also offers an arbitrary waveform data entry mode that allows individual
data points to be specified. For detailed information on creating waveforms, refer to the Sequoia
Programming Manual P/N M447353-01 and Tahoe Programming Manual P/N M447354-01.
6.2.1 Viewing Custom Waveforms on the Display
Information on user-defined, custom waveforms could be viewed on the display using the HARMONICS
menu of the MEASUREMENT screen. The harmonics could be displayed either in a tabular form or a bar
graph Refer to Figure 6-1 for an example of the information on the waveform that could be derived from
the display. After loading a waveform, and programming the output with it, the TRACE CAPTURE screen
of the MEASUREMENTS menu could be used to view it in real-time;
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