Achieve high-precision small-signal testing, 12-bit oscilloscope “core” trend

In frequent contact with engineers, I found that engineers are now facing new challenges. More and more scenarios need to accurately test high-speed small signals. Traditional 8bit oscilloscopes are embarrassing. Engineers have concerns about the test results of existing oscilloscopes. The most ideal way to improve the test accuracy is to increase the number of oscilloscope ADCs.

In frequent contact with engineers, I found that engineers are now facing new challenges. More and more scenarios need to accurately test high-speed small signals. Traditional 8bit oscilloscopes are embarrassing. Engineers have concerns about the test results of existing oscilloscopes. The most ideal way to improve the test accuracy is to increase the number of oscilloscope ADCs.

For the design of many mobile Electronic products, low power consumption is the development trend, which promotes the reduction of standby voltage or current. More power supplies require smaller ripples in DC output to improve power efficiency, or there are various types of low-power sensors used in automotive electronics, autonomous robots or medical electronics, involving many small electrical signal conversions, which are all for small amplitude Examples of higher signal measurement accuracy requirements.

Taking all these test scenarios into consideration, the core of the new 4 series MSO is a 12-bit analog-to-digital converter (ADC), which provides 16 times the vertical resolution of a traditional 8-bit ADC. Unlike some oscilloscope suppliers, their 12-bit vertical resolution is obtained through DSP calculations, rather than the true 12-bit analog-to-digital conversion implemented by hardware ADCs. The true 12-bit ADC of Tektronix is ​​built on Tek049 ASIC.

Users of the 4 series MSO not only have a true 12-bit ADC, but also can apply a new high-resolution mode, a unique hardware-based finite impulse response (FIR) filter, which further improves the vertical resolution according to the selected sampling rate Rate. The FIR filter maintains the maximum bandwidth of the sampling rate while preventing aliasing and eliminating noise from the oscilloscope amplifier and ADC above the available bandwidth of the selected sampling rate. The high-resolution mode always provides at least 12-bit vertical resolution, and expands to 16-bit vertical resolution at a sampling rate of ≤125 MS/s.

How to solve the problem of small signal test accuracy?

Tektronix faces the new generation of oscilloscopes 4 series, 5 series, and 6 series. Its hardware uses 12-bit ADCs to achieve unparalleled resolution and help engineers capture tiny signals. This is due to the Tek049 chip, this new ASIC, as the core of Tektronix’ future oscilloscopes, supports high-definition touch screen displays, up to 8 FlexChannel inputs, 12-bit vertical resolution, etc., and provides power for the next generation of oscilloscopes that modern engineers need to design.

Tek049 is an ASIC (application specific integrated circuit) newly developed by Tektronix, which is a highly integrated system-on-chip (SOC) mixed-signal ASIC. It contains 400 million transistors and 2 billion connections, forming 4 internal ADCs (modules). Digital converter) and integrated DSP (digital signal processor). Tek049 is manufactured with a 40 nm RF CMOS process and a 1927-pin fine-gap ball grid array package to create a unique chip for Tektronix’s new generation of oscilloscopes.

Achieve high-precision small-signal testing, 12-bit oscilloscope “core” trend

Figure 1 Tek049 chip

The new 12-bit ADC is currently the fastest converter in the world, with an internal operating rate of 25 GS/s, and a sampling rate per channel that is 25% higher than previous similar oscilloscopes. The 12-bit achieves 4096 vertical analog-to-digital conversion levels, and the resolution is 16 times higher than that of an oscilloscope using an 8-bit ADC. Each ADC channel is based on an interleaved continuous proximity register (SAR) structure, and each Tek049 chip includes four ADCs, achieving a total throughput of 100 GS/s.

12bit oscilloscope has become a “core” trend

Power supply design engineers are faced with more small signal testing scenarios. With the development and application of power electronics technology, many power supply ripples have become very small, especially the board-level design power rail ripple test from tens of mV to the current dozens of mV or even a few mV, the traditional 8bit oscilloscope can no longer Meet the testing needs.

For example, in the debugging of a switching device system, engineers will pay more attention to the oscillating signal at the edge of the switch. This requires the oscilloscope to ensure that the vertical direction meets a large range and at the same time have sufficient resolution to ensure that the details of the narrow oscillating signal can be captured.

Achieve high-precision small-signal testing, 12-bit oscilloscope “core” trend

Figure 2 Using 8-bit and 12-bit oscilloscopes to test the conduction signal of the switch tube

Figure 2 shows the comparison of the oscillating waveforms of the same switching circuit at the moment when the switches are turned on using oscilloscopes with different vertical resolutions. In order to test the complete waveform, it is necessary to select a larger range for the oscilloscope setting; at the same time, the engineer needs to amplify the edge oscillation to observe the details. Figure 3 and Figure 4 are the actual test results of these two oscilloscopes under the same setting conditions (250MSa/s sampling rate, 10k sample points, 2V per grid). It can be seen that the test results of the MDO4000C oscilloscope (8-bit), due to its vertical resolution limitation, have obvious quantization steps after magnification, which is basically impossible to analyze; while the waveform captured by Tektronix’s new 4 series MSO oscilloscope (12-bit) can still be magnified. Accurately reproduce the details of the oscillating signal.

Achieve high-precision small-signal testing, 12-bit oscilloscope “core” trend

Figure 3. MDO4000C oscilloscope (8bit) test results

Achieve high-precision small-signal testing, 12-bit oscilloscope “core” trend

Figure 4. New 4 series MSO oscilloscope (12bit) test results

Oscilloscope 12-bit ADC has become a trend in the testing industry. The new generation of Tektronix 12-bit oscilloscopes has greatly increased engineers’ test confidence and also provided engineers with a method to accurately test high-speed signals.

The Links:   LT104AD18F00 LM190E08-TLGG

Related Posts

Leave a Reply

Your email address will not be published. Required fields are marked *