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Three Methods for Creating and Editing Waveforms

2020-08-31  |  7 min read 

Many engineers fret over the tedious process of learning how to use waveform software or, worse yet, writing a program to generate a waveform. With modern function generators, creating and editing waveforms is no longer a source of doom and gloom.

This blog post covers three methods for creating and editing waveforms using Keysight’s Trueform Series waveform generator:

  • editing waveforms on the front panel
  • creating and editing waveforms using Excel
  • creating and editing waveforms with PathWave BenchVue software

Method 1: Editing Waveforms on the Front Panel

The simplest way to edit your waveform is on the front panel of your function generator. Modern function generators have soft buttons and dial knobs to help you do quick and basic edits.

Consider a built-in waveform editor in a Trueform Series waveform generator. Figure 1 shows the ability to select a single point or a range of points to change. By selecting a range, you can see the dark-colored portion between two markers. You can then cut the range of data, copy it, and paste it into other areas of the waveform. You can also edit the points via a spreadsheet-like table on the screen. You can even perform math on the range of points selected.

Figure 1
Figure 1. Edit a single point by selecting a range, then cutting, copying, and pasting data

Method 2: Creating and Editing Waveforms Using Excel

Microsoft Excel is a useful tool for building custom waveforms because it provides 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 generate can read and create arbitrary waveforms, or arbs, from CSV files. You can transfer the CVS file from a PC to a function generator’s front panel and load it into the waveform memory.

Figure 2 shows a screen shot of an 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 the resulting arb is plotted. Circled in red are the built-in Excel functions used to create the waveform.

Figure 2
Figure 2. An arbitrary waveform in Excel consisting of a sine wave summed with third harmonics 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 3 shows the earlier waveform generated from the spreadsheet, played back by the function generator, and displayed as a real waveform on an oscilloscope.

Figure 3
Figure 3. An arbitrary waveform created by a Keysight Trueform Series waveform generator and captured on an InfiniiVision 2000 X-Series oscilloscope

Method 3; Creating and Editing Waveforms with PathWave BenchVue Software

Keysight PathWave BenchVue is a PC software platform that allows you to easily connect, record results, and visualize measurements 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 in BenchVue.

When you open BenchVue and connect to your function generator, you will see a graphical instrument control window of your waveform generator, as shown in Figure 4. You can set up normal sine, square, ramp, pulse, triangle, noise, and pseudorandom binary sequence waveforms with desired parameters using its graphical user interface.

Figure 4
Figure 4. Keysight PathWave BenchVue’s function generator application

To create an arbitrary waveform in BenchVue, select the Create Arb button. Then you can load an existing arb from your PC or arbitrary waveform generator (AWG). You can also create a new arbitrary waveform from scratch using the waveform editor.

A Keysight BenchLink Waveform Builder Pro editor window will pop up when you click on the Create Arb button, as shown in Figure 5. You can create basic and advanced waveforms and even use the computer mouse to draw custom waveforms.

Figure 5
Figure 5. A Keysight Waveform Builder (33503A) window

One benefit of building arbitrary waveforms in BenchVue is that it allows you to sequence multiple waveforms together. You can set the waveform order and make segments repeat as many times as you want. Transferring the created arb is easy, too. You do not have to create a CSV file and manually transfer it to your AWG. BenchVue will transfer it with just a few clicks.

Summary

Using a modern AWG makes it easy to create arbitrary waveforms. If you want to select a single point or a range of points to change, you can edit the waveform in the front panel. If you want to quickly create an AWG, you can use Excel. If you want to re-create or modify an existing waveform, you can capture and save it using an oscilloscope. Then, use a USB memory drive to load the resulting CSV file into your function generator — no programming required.

If you regularly need to create arbitrary waveforms or need more advanced creation capabilities, check out the BenchVue software, available for download at http://www.keysight.com/find/benchvue.  

To learn more about Keysight’s Trueform waveform and function generators, go to http://www.keysight.com/find/function-generators