When it came to picking a scope for the lab, there was a time when the only scopes worth purchasing were Tektronix or Agilent. But that was 20 years ago.
Since then a number of competitors have entered the market with very competitive offerings. As these companies have improved reliability, quality and features of their products it no longer makes sense to buy an overpriced Tek or Keysight scope.
Both Chinese companies, Rigol was founded in 1998 while Siglent was founded four years later in 2002. These instrumentation companies have been growing their presence in North America and Europe quite rapidly and their scopes are on lab benches everywhere.
For this article, we decided to take a closer look at their products to understand how they differentiate and which one might be the better value for money. So without further ado, let’s get right down to it.
While there are many product variants with multiple channels and bandwidths, we decided to focus on an oscilloscope at a reasonable price point with specifications that will cover most applications. For the comparison we picked a two channel oscilloscope with 200 MHz of bandwidth.
Why two channel?
A two channel scope gives the ability to monitor clock and data lines for instance. If you’re doing extensive digital debugging for instance, a four channel scope might be preferred.
Why 200 MHz?
This frequency will meet most digital development and debugging applications. Whether you’re working with an Arduino or verifying the operation of a clock oscillator this is a good upper limit that will be good for a few years at least.
Rigol DS1202Z and Siglent SDS1202X-E
The DS1202Z is a two channel oscilloscope first introduced to the market in October 2019. The Siglent oscilloscope SDS1202X-E was introduced to the market two years earlier in April 2017. These two products are very similar right down to their product numbers – 1202.
While the banner specifications are identical, when you examine the specifications there are significant differences. So without further ado, let’s get into the details.
|SPECIFICATION||RIGOL DS1202Z-E||SIGLENT SDS1202X-E|
|Bandwidth||200 MHz||200 MHz|
|Sampling Rate||1 GS/s||1 GS/s|
|Memory Depth||24 Mpts||28 Mpts 🥇|
|Waveform Capture||up to 30,000 wfms/s||up to 400,000 wfm/s 🥇|
|RT Waveform Record & Playback||up to 60,000 frames||up to 80,000 frames 🥇|
|FFT size||16 kpt||1 Mpt 🥇|
|Screen||7 inch TFT-LCD (800×480)||7 inch TFT-LCD (800×480)|
|Weight||8.8 pounds||5.5 Pounds 🥇|
|Dimensions||11 x 10 x 17 inches||10 x 15 x 17 inches|
As seen from the comparison table above, the Siglent SDS1202X-E has more memory and processing capability. For instance the larger FFT size of 1 Mpt, you get 60x higher frequency resolution. Use the resolution bandwidth calculator to calculate the number in Hz/kHz/MHz. This allows you to see more closely spaced signals in the frequency spectrum.
Sampling rate indicates how frequently the oscilloscope samples the input signal. The waveform capture rate refers to how quickly an oscilloscope acquires waveforms. A high waveform capture rate gives more visual insight into how the signal behaves. It increases the probability that the oscilloscope will quickly capture transient anomalies such as jitter, runt pulses, glitches and transition errors.
The waveform capture rate of the Siglent is over 10 times faster than the Rigol which means that its ability to capture signal anomalies is significantly better. This is important when studying the impact of signal reflections due to mismatches for instance.
In addition, the waveform record and playback of the Siglent is far better than the Rigol. With higher speeds you simply see more of the signal than you see at lower speeds.
Finally, Siglent SDS1202X-E is 37% lighter – another advantage as that makes it easier to transport.
Based on the comparison and the small price difference, we feel that the Siglent 🥇 is a much better purchase than the Rigol. We look forward to seeing what other innovation this company will bring to market in the years to come.
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 If you’re not planning to upgrade from your analog scope, use this handy tool to use the period of the signal to compute its frequency.
 This post explains how to use your oscilloscope to measure the signal-to-noise ratio