Overview: This article explores the important role of oscilloscopes in electronics for effective signal analysis and troubleshooting in complex systems, highlighting the Tektronix MSO54B's advanced features.

The oscilloscope evolved from Braun\'s cathode ray tube to digital storage technology, revolutionizing electrical signal analysis. While multimeters give you static measurements (like 5 V or 1 kΩ), oscilloscopes reveal the behavior of signals. Oscilloscopes are fundamental instruments widely used across telecommunications, electrical, and electronic fields.

What Is an Oscilloscope?

An oscilloscope is an electronic measuring device that displays voltage variations over time, visualizing electrical signals as waveforms. It provides a visual representation of electrical signals that reveals signal shape, peak voltage, frequency, phase difference, pulse width, delay time, rise/fall times, and transient events.

It also reveals dynamic signal characteristics such as sine, square, triangular, sawtooth, and complex waveforms. This visualization capability allows for deeper analysis and a better understanding of circuit behavior. They are an important tool for troubleshooting, analyzing, debugging, and understanding how electrical signals behave in real-time.

Key Components of an Oscilloscope

The essential components, as shown in Fig. 1, include

  • Display

  • Horizontal Section

  • Vertical Section

  • Trigger

  • Connectors and Probes

Key Components of oscilloscope

Fig. 1 Key Components of Oscilloscope (Model: DSOX2004A Oscilloscopes by Keysight Technologies) Source: oemsecrets

Display

The display system of an oscilloscope has evolved over the years, from traditional cathode-ray tubes to modern digital displays. Modern oscilloscopes use digital displays such as LCD, OLED, and TFT technologies. Digital oscilloscopes can show multiple measurements simultaneously, including frequency, amplitude, and timing relationships.

Additionally, it shows multiple channel waveforms in different colors, grid lines, on-screen measurements and cursors, waveform storage, zoom, menu systems and control interfaces, mathematical functions, and FFT analysis.

Horizontal Section

The horizontal section controls the time base or sweep of the instrument. It allows for positioning the signal on the time (X axis) as well as adjusting the time-based scaling options. The primary control is the seconds-per-division (Sec/Div) selector switch. It includes a horizontal position knob to shift the waveform left or right on the screen.

Vertical Section

The vertical system controls the amplitude of the signal, allowing adjustments on how the waveform stretches or compresses vertically on the display along the Y-axis. The vertical scale is controlled by a rotary knob on the unit and adjusts the number of volts per division on the instrument. This section handles signal amplification and attenuation.

Triger

To clearly display and analyze a signal, the instrument needs a consistent start point for data capture, which is called triggering. The trigger works by starting the horizontal sweep at precisely the same point of a repeating waveform each time, which makes the signal stationary. This synchronized capture prevents constant shifting across the screen, allowing for accurate measurement and analysis of the signal.

Advanced triggers include pulse width, rise/fall time, pattern, and protocol-specific types. Among various trigger types, edge triggering is the most common type that activates when signals cross a set voltage level in a specific direction.

Connectors and Probes

The are typically 2-4 main BNC connectors for connecting probes to measure signals. Each channel has independent controls for voltage sensitivity. The probe is the physical device that connects the circuit under test to the oscilloscope, transmitting the electrical signal for measurement and analysis.

Key Parameters of an Oscilloscope

The two most important parameters to consider when buying an oscilloscope are bandwidth and sampling rate.

Bandwidth

Bandwidth refers to the highest frequency signal that the oscilloscope can accurately measure, defined as the frequency at which a sine wave input is attenuated by -3 dB (i.e., to about 70.7% of its true amplitude). For reliable measurements, the oscilloscope's bandwidth should be at least three to five times higher than the highest frequency component in the signal.

Sampling Rate

Sampling rate is the speed at which the oscilloscope's analog-to-digital converter samples the input signal, measured in samples per second (e.g., GSa/s). To accurately reconstruct fast-changing signals and avoid aliasing, the sampling rate should be at least three to four times the oscilloscope's bandwidth.

The sample rate splits up while introducing additional channels. For example, a 4-channel oscilloscope with a maximum sampling rate of 1 GSa/s (1 billion samples per second) might provide:

  • 1 GSa/s when using a single channel

  • 500 MSa/s per channel when using two channels

  • 250 MSa/s per channel when using all four channels

An Oscilloscope to Consider

Oscilloscopes are available in a broad spectrum, ranging from basic entry-level models to advanced high-end instruments, designed to meet diverse user requirements, budgets, and applications. One such professional model is detailed below

Tektronix MSO54B Mixed Signal Oscilloscope

The Tektronix MSO54B, as shown in Fig. 2, is a flagship mixed-signal oscilloscope that has the largest display and the largest number of channels. It is a powerful tool for design validation, debugging, and compliance testing.

Tektronix MSO54B Mixed Signal Oscilloscope

Fig. 2: Tektronix MSO54B Mixed Signal Oscilloscope. Source: oemsecrets

Key specifications include

  • The 4, 6, or 8 FlexChannel inputs provide exceptional versatility.

  • The bandwidth options range from 350 MHz to 2 GHz, with upgrade paths that allow users to purchase and scale up as requirements change.

  • High sample rate of 6.25 GS/s enables the oscilloscope to capture very fast transient events.

  • The standard 62.5 M point record length with optional upgrades allows for capturing long signal sequences or analyzing complex signal sequences.

  • The >500,000 waveforms/second capture rate significantly increases the probability of catching rare, intermittent events that might be missed.

  • The 12-bit ADC with up to 16-bit high-resolution mode provides 4,096 to 65,536 vertical digitization levels, offering much finer detail than traditional 8-bit oscilloscopes (256 levels).

  • It has advanced trigger types including edge, pulse width, logic, setup/hold, parallel bus, sequence, and optional video/RF triggers.

  • The 15.6-inch HD touchscreen with multi-touch interface improvesnvisibility of complex signals.

  • The standard and optional analysis packages enable troubleshooting and characterization across various application domains.

  • Multiple USB ports and network connectivity facilitate data > transfer, remote operation, and integration into automated test > environments.

Hence, Tektronix MSO54B is a top-tier oscilloscope for engineers and researchers who demand flexibility, precision, and advanced analysis tools for complex electronic systems.

To conclude, key manufacturers of oscilloscopes include Keysight Technologies, Tektronix, Rohde & Schwarz, Siglent Technologies, Rigol Technologies, B&K Precision Corporation, GW Instek (Good Will Instrument Co., Ltd), Pico Technology Limited, etc. A few specialized & handheld oscilloscope manufacturers are also available, like Fluke Corporation.

Oemsecrets.com features a wide range of oscilloscopes from key manufacturers, allowing users to compare prices and stock availability from global distributors such as Digikey, Mouser, Avnet, Arrow, Farnell, TTI, Buerklin, and more.

Summarizing the Key Points

  • Oscilloscopes visualize voltage over time, revealing signal shapes, frequency, phase, and transient events, enabling in-depth circuit behavior analysis.

  • Key oscilloscope components include the display, horizontal & vertical sections, trigger system, and connectors/probes.

  • Bandwidth and sampling rate are crucial specs; bandwidth defines the > maximum frequency accurately measured, and sampling rate is > required to reconstruct signals correctly.

Reference

Fushshilat, I., & Barmana, D. (2018). Low cost handheld digital oscilloscope. IOP Conference Series Materials Science and Engineering, 384, 012027. https://doi.org/10.1088/1757-899x/384/1/012027

Zhu, J., Wang, Y., Zhao, K., & Wang, Y. (2024). Oscilloscope measurement bandwidth expansion using frequency response compensation. IEEE Access, 12, 49772--49778. https://doi.org/10.1109/access.2024.3384381

APPLICATION OF OSCILLOSCOPE TECHNOLOGY IN THE EARLY 21ST CENTURY: A SYSTEMATIC LITERATURE REVIEW Theophilus Pandin. Widya Mandala Catholic University Surabaya.DOI:10.20944/preprints202106.0090.v1

Rohde & Schwarz. (2020, January 27). Understanding basic oscilloscope operation [Video]. YouTube. https://www.youtube.com/watch?v=zqCbJo6mo7o

GreatScott! (2021, August 8). Everything you need to know when buying/using an Oscilloscope! EB#49 [Video]. YouTube. https://www.youtube.com/watch?v=d58GzhXKKG8

Oemsecrets. (n.d.). MSO54B - Compare distributor prices & inventory | oemsecrets.com. oemsecrets.com. https://www.oemsecrets.com/compare/MSO54B