Siglent SDS1102X Oscilloscope Reviewed by Paul Danzer, N1II [email protected] The Siglent SDS1102X is a 100 MHz, two channel digital storage oscilloscope. It features an 8-inch color LCD screen and includes a number of features that are useful in the amateur workshop. The first thing you might notice after unpacking the SDS1102X is the front panel layout. There is a branch of engineering known as human factors, which is devoted to ensuring that equipment is designed so it can be operated accurately, safely, and within the limits of two hands and one set of eyes. For example, the main tuning knob on a transceiver is most likely the largest knob, easily selected. Functions used less often have smaller knobs, and the least used may have very tiny knobs, rear panel locations, or be assigned to menus. This oscilloscope was definitely designed with human factors in mind! In addition to the supplied 160-page PDF manual, there’s a Quick Start booklet that is laid out almost as a software flowchart — and without this guidance you might miss being able to take advantage of some of the scope’s capabilities. First Steps The SDS1102X comes with two probes. In addition to the “grabbing” probe hook ends, several other probe ends are enclosed. As with any scope, the first step is to make sure the probes are adjusted correctly. The front panel square wave test point allows you to make this quick adjustment — if needed. The next step is to check the manufacturer’s website for any firmware updates, as there may have been a new release since the scope was manufactured (it originates in China). The review unit did not come with clear update instructions, but according to Siglent, better instructions will be available by the time this review reaches print. The firmware is downloaded from Siglent’s website as a compressed .rar file. If your compression software won’t uncompress a .rar file, download a copy of 7-ZIP (www.7-zip.org). After uncompressing the file, search for a file with the suffix .ads. Copy this file (and only this file) to a flash drive and then follow the manufacturer’s instructions. Updating is done through the UTILITY menu. The process may take a while, so stay hands-off until you get a message that the update is complete. Siglent supplies a USB cable and EasyScopeX software to allow control of the scope from your PC as well as capture and storage of screen shots of the scope display (see the sidebar, “EasyScopeX Utility Software”). EasyScopeX is not required to operate the scope, so you can, if you wish, skip the software installation. I installed the software and used it to capture the screens shown in this review. Another 160-page PDF manual details commands for programming and controlling the scope from your PC. Don’t worry — only one page was needed to explain how to use EasyScopeX. Once it is up and running, the screens are relatively self-explanatory. Let’s Look at the Screen The scope screen in Figure 4 is probably the best way to explain how to operate this ­ scope. The waveform displayed is channel 1 (one of the two channels) with its probe connected to the calibration square wave output on the scope front panel. All you have to Bottom Line This 100 MHz oscilloscope has a knockout color display but requires a great deal of learning to use its many features. There is very little around your shack or workbench that the scope cannot do. do to get this picture is press the blue AUTO SETUP button, wait a second or two, and your waveform appears, perfectly scaled to a matching horizontal sweep rate and vertical gain. You can, of course, set the sweep rate, vertical gain, trigger mode, and trigger point manually, but the automatic function is valuable for a fast look. The display tells the rest of the story. Starting at the top left, the legend shows the display is triggered (that is synchronized to the waveform), and the horizontal scale is 200 µs per division. The next legend on the top is the trigger delay, and the zero means there is no delay set. The delay and other trigger settings are adjustable from the front panel. On the right-hand side of the screen, the square wave frequency is measured as 1 kHz. For irregular but repetitive waveforms, the circuits pick up an identical point on each “cycle” that may not correspond to the base frequency, so a little caution is in order. Below the frequency, the sample rate is shown as 5 Ms/S (megasamples/second) and the number of sample points across the screen is 14,000. Press the RUN/STOP button and these values will be saved for further examination. If you are used to older analog oscilloscopes, you might notice that there are no controls or settings for ALTERNATE or CHOPPED for the two input channels. If you change the setting to use both probes, a second box opens to show the status of channel 2. In addition, the sample rate goes Reprinted with permission from April 2016 QST ARRL, the national association f

Table 3 Siglent SDS1102X Key Parameters Bandwidth:100 MHz Real-time sampling rate up to 1 Gigasamples/second Rise time: approximately 3.5 ns maximum Vertical resolution – 8 bits (1 part in 256) DC gain accuracy: 3% to 4% Horizontal (time base) accuracy: ±25 ppm Record length: 14 megapoints Trigger modes: Edge, Pulse, Window, Runt, Interval, Time out (Dropout), and Pattern Serial bus triggering and decode (supports data protocols such as UART and RS-232) Video triggers for HDTV Vertical scale 500 µV/div to 10 V/div History waveform record function; maximum recorded waveform length is 80,000 frames...

p ­ icture I selected the MATH button on vertical panel and pressed the FFT soft key so that the scope functioned as a spectrum analyzer. The spectrum on the screen (see Figure 7) with the accompanying legends shows 10 kHz per division as the horizontal scale. A count of energy spikes between each division is 10, corresponding to the envelope measurement of 1 kHz in Figure 6. The result: “By accident” I found that this old signal generator had a serious problem, noticed and measured with the capabilities of an advanced digital scope! Perhaps it is time to buy a new signal generator. Figure 4...