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Create Arbitrary Waveform for Use in a Function Generator

2021-03-18  |  8 min read 

Introduction

Advances in software, microprocessors, and display technology have expanded the capabilities of modern function generators. The latest models can produce a variety of signals, including common waveforms, arbitrary waveforms, and sophisticated modulated waveforms.

The Keysight EDU33210 Series function / arbitrary waveform generator (AWG) comes with all the standard signals and features you need now and for testing tomorrow’s designs. It has 17 built-in arbitrary waveforms and six built-in modulations to get you set up and testing immediately. It also comes with Keysight PathWave BenchVue application software to enable you to configure instruments quickly from your PC. This powerful software provides you with integrated instrument control, auto data logging, remote data access, and easy file sharing — all from one PC.

This blog post discusses how the EDU33210 Series can create arbitrary waveforms for use in function generators.

Creating Arbitrary Waveforms Doesn’t Have to Be Difficult

Creating arbitrary waveforms on a modern function generator or AWG is not as difficult as you might think.

Let’s look at two examples:

  • Create an arb from scratch using Excel and then transfer it to an AWG.
  • Create arbitrary waveform with PathWave BenchVue software.

Create arbitrary waveforms using Excel

Excel is a useful tool for building custom waveforms. It includes built-in advanced mathematical functions, it can handle large amounts of data (waveform points), and it is already on just about everybody’s computer.

How do you get the waveform from Excel to the function generator? Excel and modern function generators have something in common — the CSV file format. Excel can read CSV files, and you can save Excel spreadsheets as CSV files. Modern function generators can read and create arbs from CSV files. You can transfer the CVS file from a PC to a function generator front panel and load it into the waveform memory.

Figure 1 shows a screenshot of the Excel spreadsheet consisting of a sine wave summed with third harmonic noise and random noise. You can graph the tabulated points in column A for quick viewing and then save them in a file. Notice that the resulting arb is plotted. Circled in red are the built-in Excel functions used to create the waveform.

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Figure 1. An arbitrary waveform in Excel showing a sine wave summed with third harmonic noise and random noise

You can save the Excel spreadsheet as a CSV file. Using a USB memory stick, you can upload it to a function generator. Figure 2 shows the earlier waveform generated from the spreadsheet, played back by the function generator, and displayed as a real waveform on an oscilloscope.

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Figure 2. An arbitrary waveform created by an AWG and captured on a Keysight InfiniiVision 2000 X-Series oscilloscope

As you can see, Excel provides an easy, no-cost way to create an arbitrary waveform. The CSV file format provides a means to quickly transfer an arb to an AWG.

Create arbitrary waveforms in BenchVue

The BenchVue PC software platform allows you to easily connect, record, and obtain results across multiple test and measurement instruments without programming. Plug-and-play functionality enables you to connect your instrument to your PC and immediately begin controlling it.

When you open BenchVue and connect to your function generator, you’ll see a graphical instrument control window of your waveform generator, as shown in Figure 3. You can set up normal sine, square, ramp, pulse, triangle, noise, PRBS, and DC waveforms with desired parameters using its graphical user interface.

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Figure 3. BenchVue’s function generator application

To create an arbitrary waveform in BenchVue, select the arbitrary waveform icon button. Then you can load an existing arb from your PC or AWG.

Arbitrary Waveforms Used in Function Generators

Arbitrary waveform design and use have had limited flexibility until recently. To change a waveform, you had to generate a new signal. While you might have been able to change one or two points by hand, changing large parts of the waveform required a redesign.

Keysight PathWave BenchVue Waveform Builder Pro gives you access to advanced signal-creation and editing capabilities without spending hours programming. You can create a wide variety of custom pulses and patterns using the arbitrary waveform capabilities of a function generator or AWG to define the desired shape and parameters. The result is quicker and easier custom waveform creation combined with deeper analytical insight into your signals.

As an engineer, you would like to reuse as much of your work as possible, whether it’s programming or a circuit design. With Keysight’s EDU33210 Series, you can reuse, re-sort, and change parameters on your arbs to build a whole new signal. This approach saves time and increases your confidence in the new signal because you are reusing proven waveforms.

Summary

Creating and editing arbitrary waveforms on a modern function generator or AWG is now easy. If you want to re-create or modify an existing waveform, you can capture and save the waveform using an oscilloscope. Then, use a flash memory drive to load the resulting CSV file into your AWG. EDU33210 Series builds on the features of its predecessor to create a more efficient workflow.

With PathWave BenchVue Waveform Builder Pro, you get advanced signal-creation and editing capabilities without spending hours programming.

If you regularly create arbitrary waveforms and need higher bandwidth, check out the Keysight Trueform Series waveform generator:

  • 33500B Series Trueform waveform generators, 20 and 30 MHz
  • 33600A Series Trueform waveform generators, 80 and 120 MHz

For more information on the Keysight Trueform Series waveform generators, please visit here.

For more information on the EDU33210 Series function / arbitrary waveform generator, please visit here.

If you regularly create arbitrary waveforms and need more advanced creation capabilities, check out the BenchVue software, available for download here.

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