On this planet of engineering, precision is paramount. Whether or not it’s performing high quality assurance on cutting-edge electronics or debugging complicated techniques, the accuracy of measurements could make or break a venture. That is the place the idea of vertical accuracy in oscilloscopes turns into essential, it refers to how intently the voltage readings match the precise voltage of the sign being measured. Reaching a excessive vertical accuracy will depend on two components: the variety of analog-to-digital converter (ADC) bits and the noise flooring of the oscilloscope.

The position of ADC bits

The horizontal axis of an oscilloscope represents the time base (seconds per division or s/div), whereas the vertical axis exhibits the voltage (volts per division or V/div). Vertical accuracy is about how precisely the oscilloscope shows the voltage of the sign, which is important for visible illustration and exact measurements. The nearer the voltage studying on the oscilloscope display is to the precise sign voltage, the upper the vertical accuracy.

To attain the optimum studying, engineers want oscilloscopes with the best variety of ADC bits and the bottom noise flooring. Increased ADC bits present extra vertical decision, resulting in extra exact sign visualization, whereas a decrease noise flooring minimizes the oscilloscope’s impression on the sign. This mixture ensures the oscilloscope supplies probably the most correct illustration of the sign, minimizing any distortion or noise that might have an effect on the measurements.

To take a look at this in additional element, an oscilloscope with an 8-bit ADC can encode an analog enter into 256 distinctive ranges of conversion (2⁸ = 256). Every further bit doubles the variety of ranges of conversion. Due to this fact, 9 bits present 512 ranges (2⁹ = 512), 10 bits present 1,024 ranges (2¹⁰ = 1,024), and so forth.

Oscilloscopes with a 14-bit ADC can encode the analog enter into 16,384 ranges (2¹⁴ = 16,384), which is 4x the decision of a mean 12-bit ADC oscilloscope and 64 instances the decision of an 8-bit ADC. This greater decision permits the oscilloscope to seize finer particulars of the sign, offering a extra correct illustration.

Now think about how this is applicable to an oscilloscope with a vertical setting of 100 mV per division and eight vertical divisions. The oscilloscope’s full display equals 800 mV (100 mV/div * 8 divisions). With an 8-bit ADC, the total display (800 mV) is split into 256 ranges, leading to a decision of three.125 mV per degree. Compared, a 14-bit ADC divides the identical 800 mV into 16,384 ranges, attaining a decision of 48.8 µV per degree. This vital improve in decision permits engineers to detect and measure a lot smaller adjustments within the sign, as proven in Determine 1.

Determine 1 Because the variety of ADC bits will increase, so does the variety of ranges of conversion. This leads to the next vertical decision that permits engineers to measure a lot smaller adjustments within the sign. Supply: Keysight

The significance of a low noise flooring

Whereas a excessive variety of ADC bits is important for vertical accuracy, it’s not the one issue. The noise flooring of the oscilloscope additionally performs a important position. This refers back to the intrinsic noise generated by the oscilloscope itself, which may intervene with the sign being measured, resulting in inaccurate readings.

All digital units, together with oscilloscopes, generate some degree of noise. Nevertheless, the aim is to reduce this as a lot as potential. A decrease noise flooring signifies that the oscilloscope has much less impression on the sign, leading to extra correct measurements. Moreover, you gained’t be capable of see sign element smaller than the noise of the oscilloscope. That is particularly essential when measuring very small voltages, the place even a small quantity of noise can considerably distort the readings.

For instance, Determine 2 exhibits an oscilloscope measuring a 53 mV sign. At 2 mV/div, this oscilloscope has a noise flooring of lower than 50 mV_RMS. Utilizing this oscilloscope, you may seize the very small 53 mV sign as a result of the noise flooring is low sufficient. This sign could be misplaced within the noise flooring of different general-purpose oscilloscopes that are likely to exceed 100 mV_RMS.

Determine 2 An oscilloscope with a noise flooring of <50 mV_RMS captures a small 53 mV sign that’s misplaced within the noise flooring of different general-purpose oscilloscopes. Supply: Keysight

Combining excessive ADC bits and low noise flooring

The mix of a excessive variety of ADC bits and a low noise flooring leads to the best vertical accuracy. This ensures that the oscilloscope supplies probably the most correct illustration of the sign, permitting engineers to make exact measurements and keep away from expensive errors.

As an illustration, an oscilloscope that might function a 14-bit ADC and a noise flooring of lower than 50 µV_RMS at 2 mV/div and a 1 GHz bandwidth on a 50-Ω enter would offer distinctive vertical accuracy, enabling engineers to detect even the smallest adjustments within the sign. This distinction can impression an engineer’s skill to achieve perception, perceive, debug and characterize designs. As well as, inaccurate outcomes from an oscilloscope can improve threat within the improvement cycle instances, manufacturing high quality and probably the elements chosen. Engineers want to have the ability to depend on instruments and expertise that may give them the very best insights and accuracy.

Reaching a excessive vertical accuracy

It’s important to acknowledge that not all oscilloscopes are made equal. Engineers have to go for the best ADC bit, mixed with a low noise flooring, to attain the best vertical accuracy. This mixture ensures the oscilloscope precisely represents the sign, minimizing any distortion or noise that might have an effect on the measurements. Excessive vertical accuracy is important for exact measurements, decreasing errors, and saving time and sources. By investing in oscilloscopes with excessive vertical accuracy, engineers can belief their measurements, resulting in extra environment friendly debugging.

Michelle Tate is at the moment a Product Advertising and marketing Supervisor at Keysight Applied sciences for InfiniiVision Oscilloscopes.  She beforehand labored within the semiconductor business with Texas Devices’ wi-fi connectivity and brushless-DC motor drivers and acquired her Bachelor of Electrical Engineering from The College of Texas at Austin.

Associated Content material

• Maximize the accuracy of your oscilloscope measurements
• Understanding FFT vertical scaling
• How you can make higher measurements together with your oscilloscope or digitizer
• Oscilloscope cursors complement different measurement instruments
• FFTs and oscilloscopes: A sensible information

The put up Not all oscilloscopes are made equal: Why ADC and low noise flooring matter appeared first on EDN.