Let's take a look at the new Siglent SDG1032X Arbitrary function generator. We're looking at yet another example of the closing gap between hobbyist and pro gear - the growing feature set and capabilities of entry-level equipment continues to improve. Take a look at the video for this article to see a full dive into the user-experience.
What's an arbitrary function generator?
An Arbitrary Function generator (or "arb") is used to generate voltage signals for designing and testing circuits. These could be in the form of various standard waves (sine, square, etc.) used to test audio, radio or power circuits. Sometimes, we might need something a little more specific, like a 30% duty-cycle square wave, or some math function. Enter the arb. An arbitrary function can be a function we describe using a mathematical function like y = sin(x) + sin(2x), specify as the line joining several data-points, or even hand draw on a computer screen.
Arbs usually come with many built-in functions as standard.
First impressions
The look and feel of the SDG1032X is top notch. The power switch feels positive and robust, the case has rubber corner-bumpers and a sturdy tilting-bale. As for the user interface, the 4.3" graphical display is a welcome upgrade to the usual strip-style character displays. User buttons are soft-touch but retain a positive. The rotary encoder feels pretty standard.
Performance experiments
Before we begin - I'm performing these tests with some pretty ordinary looking BNC-BNC leads. Don't be discouraged though, I'm guessing these leads are probably a pretty standard quality for the home maker and so are probably a pretty good representation of the signal you'll get at the end of a lead.
The SDG1032X boasts some impressive maximums of 30MHz and 20Vpp. Of course, these are the flagship specs so I decided to do a quick experiment to see a realistic use envelope. The plot below shows the maximum output voltage vs. the output frequency. The test was conducted with both sine and square waves, (which had identical ranges in the end) at a zero offset. The result is pretty pleasing - the 20Vpp maximum can be held all the way to 10MHz for both square and sine waves.
I also decided to take a look at the square wave performance at a more sensible voltage of 2Vpp. Note that this plot starts at 1kHz. Here's what I found:
If you're wondering what the wave shapes look like, I've included a screen-grab of 1,10 and 30MHz. I've also included a waveform for both channels - I'm using dissimilar leads so it's interesting to see the effect that each lead has on overshoot and rise-time. Siglent boasts rise/fall times of less than 4.2ns, but with my crusty leads, I'm getting slightly over that.
1 MHz
10 MHz
30 MHz
The Easy Wave software
This software allows you to prescribe your own arbitrary functions as well as remote control the arb. One trap for installation is that you need to download and install the NI-VISA drivers - this is covered in the installation manual which almost nobody would read at first. Once you install the NI-VISA software, you can run the EasyWave.msi installer, plug your arb into your computer and you're ready to go.
Watch this article's video to see the Easy Wave software in action.
Tips and Tricks
Turn off the beeper from the Utility>System menu and, while you're at it, set the turn on behaviour to Last. The SDG1032X usually wants to power-up in default mode which means that if you turned the beeper off, when you power-cycle the unit then you find the thing beeping at you again for every action you make.