Oscilloscopes are essential tools for engineers, technicians, and researchers working with electronic signals. Choosing the right oscilloscope and understanding its technical specifications can significantly impact measurement accuracy and efficiency. This FAQ addresses some of the most important aspects of oscilloscope performance and application.

    General Questions
    What is an oscilloscope?
    An oscilloscope is an electronic test instrument used for observing the precise shape and timing characteristics of electrical signals over time.

    • Provides a visual representation of voltage vs. time on a two-dimensional graph.
    • Enables measurement and analysis of signal parameters such as amplitude, frequency, phase, noise, and distortion.
    • Essential for troubleshooting, validation, and characterisation in R&D, manufacturing, and repair environments.

    What are the different types of oscilloscopes?
    Oscilloscopes vary based on signal acquisition and display technology.

    • Analog Oscilloscopes: Use a cathode ray tube (CRT) to directly deflect an electron beam across the screen.
    • Digital Storage Oscilloscopes (DSOs): Sample input signals, convert them to digital data, and store them for processing and display.
    • Mixed-Signal Oscilloscopes (MSOs): Combine analogue channels with digital (logic) channels to simultaneously observe and correlate analogue and digital signals.
    • Digital Phosphor Oscilloscopes (DPOs): Enhance waveform intensity grading and acquisition rate for better visualisation of dynamic signal behaviour.

    What is the difference between an analogue and a digital oscilloscope?
    The core difference lies in how signals are processed and displayed.

    • Analogue: Real-time, continuous waveform representation via electron beam on CRT.
    • Digital: Converts analogue input into digital samples using an ADC, allowing advanced processing such as storage, measurement, and zoom functions

    What does real-time vs. equivalent-time sampling mean?
    These modes determine how data is acquired and processed.

    • Real-time sampling: Captures waveform in a single acquisition. Ideal for single-shot or non-repetitive signals.
    • Equivalent-time sampling: Reconstructs periodic signals over multiple acquisitions, offering higher effective resolution.

    How do I choose an oscilloscope?
    Selecting the right oscilloscope depends on your specific application and measurement needs. Key considerations include:

    • Bandwidth: Ensure the oscilloscope’s bandwidth is 2.5 to 5 times greater than the highest frequency component of the signal under test.
    • Sampling Rate: The sampling rate should be at least 5 times the maximum signal frequency to avoid aliasing and ensure signal fidelity.
    • Number of Channels: Choose the number of analogue and digital channels based on whether you need to observe multiple signals simultaneously.
    • Memory Depth: Deeper memory enables high-resolution captures over longer durations—important for protocol analysis and signal troubleshooting.
    • Vertical Resolution: A higher resolution (e.g., 12-bit ADC) allows more precise voltage measurements and better visibility of low-amplitude signals.
    • Triggering Capabilities: Look for advanced triggering for capturing complex and transient signal events.

    Technical Specifications
    Why Is Bandwidth Important in Oscilloscopes, and How Does It Affect Measurement Accuracy?
    Bandwidth determines how well an oscilloscope can accurately display signals of different frequencies. To measure a signal with minimal distortion, the oscilloscope's bandwidth should be at least 5 times the highest frequency component in the signal.

    • Determines the highest frequency component of a signal that can be accurately captured (~3 dB point).
    • Insufficient bandwidth causes attenuation and signal distortion, leading to inaccurate amplitude and waveform representation.
    • For high-speed digital signals and RF applications, selecting an oscilloscope with the right bandwidth ensures precise waveform reproduction.

    What Is the Role of Maximum Real-Time Sampling Rate in Accurately Reconstructing High-Frequency Signals?
    Sampling rate determines how frequently an oscilloscope digitises an input signal and impacts the fidelity of signal reconstruction.

    • To avoid aliasing, the Nyquist criteria states that the oscilloscope should sample at a rate of at least 2.5 to 5 times the highest signal frequency.
    • A higher sampling rate allows for better reconstruction of high-speed signals, ensuring that signal edges and transients are captured accurately.
    • Essential for applications in RF, high-speed digital design, and signal integrity analysis.

    How Does a High Waveform Capture Rate (e.g., 1,000,000 wfms/s) Enhance Transient Event Detection?
    A high waveform capture rate improves an oscilloscope’s ability to detect rare and intermittent signal anomalies.

    • Helps in identifying glitches, dropouts, and jitter, which may be missed at lower capture rates.
    • Increases the probability of observing signal defects in digital and analogue systems.
    • Reduces the dead time between acquisitions, making it easier to visualise subtle timing variations.

    How Does Increased Memory Depth (e.g., 500Mpts) Benefit the Analysis of Long-Duration Signal Events?
    Memory depth determines how long an oscilloscope can store captured data at a given sampling rate.

    • Deeper memory enables high-resolution acquisition over extended time periods, allowing detailed signal analysis.
    • Useful for serial protocol debugging, power analysis, and long-duration transient capture.
    • Prevents loss of critical data when capturing long signal sequences at high sampling rates.

    What is rise time in an oscilloscope?
    Rise time is the time required for a signal to transition from a low to a high value (typically 10% to 90%).

    • Critical for characterising high-speed edges and transitions.
    • Approximated by: Rise Time (sec) ≈ 0.35 / Bandwidth (Hz).
    • A shorter rise time indicates a faster and more responsive measurement system.

    How Does Vertical Resolution Impact Measurement Precision, and What Are the Benefits of a 12-bit ADC Over an 8-bit ADC?
    Vertical resolution refers to the oscilloscope's ability to differentiate small voltage variations.

    • An 8-bit ADC offers 256 discrete levels, while a 12-bit ADC provides 4,096 levels, significantly improving the ability to capture finer signal details.
    • A higher vertical resolution is particularly beneficial for low-noise and high-precision applications, such as power integrity analysis and sensor measurements.
    • It allows for better measurement of small signal variations superimposed on a larger waveform.

    Usage and Applications
    How do I properly set up an oscilloscope?
    Proper setup ensures accurate and stable waveform acquisition.

    • Connect probe securely to input channel.
    • Match probe attenuation setting with oscilloscope input.
    • Ground probe appropriately to minimize noise.
    • Set correct voltage (vertical) and time (horizontal) scales.
    • Adjust trigger level and mode to stabilize the waveform.

    How can I prevent signal distortion?
    Distortion can arise from incorrect probing or environmental issues.

    • Use probes with matched impedance (typically 10:1).
    • Avoid ground loops; use shortest possible ground lead.
    • Set oscilloscope bandwidth limit to reduce high-frequency noise if appropriate.
    • Use high-quality, short-length cables to minimize inductance and resistance.

    When Is Battery-Powered Operation Beneficial in an Oscilloscope?
    Battery-powered oscilloscopes provide mobility and isolation, making them useful in specific scenarios:

    • Field measurements where AC power is unavailable.
    • Automotive and aerospace testing, allowing measurements inside vehicles or aircraft.
    • High-voltage isolation, reducing the risk of ground loops when measuring floating signals.
    • Portable troubleshooting, offering flexibility in environments where power sources are limited.

    What is triggering, and why is it important?
    Triggering synchronises waveform display for repetitive signal observation.

    • Ensures a stable and repeatable display of periodic signals.
    • Trigger types:
      • Edge: Detects rising/falling edges.
      • Pulse Width: Detects pulses of specific duration.
      • Video: For TV signals.
      • Pattern and Logic: For MSO operation.
    • Critical for analysing Intermittent or asynchronous events.

    What Should Be Considered When Selecting an Oscilloscope for Power Sequencing and 3-Phase Power Analysis?
    Power analysis applications require specialised oscilloscope features, including:

    • Multiple isolated channels for safe differential voltage and current measurements.
    • High-resolution ADCs (12-bit or higher) to capture precise power variations.
    • Advanced triggering and analysis functions, such as harmonics, inrush current, and power factor calculations.
    • Support for differential probes and current clamps to measure three-phase systems accurately.

    How Do Multiple Analogue Channels and High Vertical Resolution Facilitate Testing in Embedded and Power Semiconductor Applications?
    Oscilloscopes with multiple channels and high resolution enable comprehensive testing of embedded systems and power semiconductors.

    • Multi-channel support allows simultaneous observation of digital and analogue signals in mixed-signal designs.
    • Higher resolution enhances detection of small anomalies in power electronics, motor drives, and switching regulators.
    • Protocol decoding (I2C, SPI, CAN, etc.) simplifies embedded system debugging.
    • FFT and harmonic analysis provide deeper insight into signal integrity and spectral characteristics.

    How Can I Capture Single-Shot Signals or Sporadic Events Using an Oscilloscope?
    Capturing single-shot or infrequent signals requires the use of the single trigger mode. This setting allows the oscilloscope to wait for a specific trigger event, capture it once, and then freeze the display for analysis.

    • Utilise advanced trigger options such as edge, pulse width, runt, or pattern triggers to detect specific events.
    • Adjust persistence mode to retain the waveform on-screen for better visibility of rare events.
    • Use high waveform capture rates to increase the likelihood of detecting transient occurrences.

    How do I measure frequency and voltage using an oscilloscope?
    Use on-screen tools for precise measurements.

    • Voltage: Measure peak-to-peak (Vpp), RMS, or average voltage using cursors or built-in measurement functions.
    • Frequency: Measure the period (T) and apply f=1Tf = frac{1}{T}f=T1.
    • Ensure the signal is cantered and scaled appropriately for clear cursor placement.

    Troubleshooting & Maintenance
    Why is my oscilloscope not displaying a waveform?
    Several common setup issues may prevent signal visualisation.

    • Verify probe is connected and functional.
    • Confirm correct input channel is selected.
    • Adjust vertical and horizontal scales to appropriate ranges.
    • Check trigger level, slope, and mode settings.

    How do I calibrate my oscilloscope?
    Calibration ensures measurement accuracy.

    • Most digital scopes offer self-calibration via software.
    • For manual calibration:
    • Connect probe to the external square wave terminal.
    • Adjust probe compensation to match the expected square waveform shape.
    • Select self-calibrate from the utility menu
    • Annual or periodic factory calibration may be required for compliance and traceability.

    How should I maintain my oscilloscope for long-term use?
    Proper care extends lifespan and performance.

    • Store in a clean, dry, temperature-controlled environment.
    • Avoid mechanical shock and exposure to ESD.
    • Regularly inspect and clean probes and connectors.
    • Keep firmware updated as per manufacturer guidelines.

    By understanding these key oscilloscope specifications and features, engineers and technicians can make informed decisions when selecting and using an oscilloscope for their specific applications. Whether troubleshooting digital circuits, analysing power systems, or capturing transient events, the right oscilloscope features can significantly enhance measurement accuracy and testing efficiency.

    SeriesBandwidthSample RateMemory DepthChannels8 Bit12 BitMixed Signal
    DS700003.5 GHz - 5 GHz20 GSa/s2 Gpts4YesNoNo
    MSO8000600 MHz - 2 GHz10 GSa/s500 Mpts4YesNoYes
    MHO5000500 MHz - 1 GHz4 GSa/s500 Mpts4/6NoYesYes
    DHO5000500 MHz - 1 GHz4 GSa/s500 Mpts4/8NoYesNo
    DHO4000200 MHz - 800 MHz4 GSa/s500 Mpts (optional)4NoYesNo
    MSO7000100 MHz - 500 MHz10 GSa/s500 Mpts (optional)4YesNoYes
    MHO2000200 MHz - 350 MHz2 GSa/s500 Mpts4NoYesYes
    MSO500070 MHz - 350 MHz8 GSa/s200 Mpts (optional)2/4YesNoYes
    MSO2000A100 MHz - 300 MHz1 GSa/s56 Mpts (optional)2YesNoYes
    DHO900125 MHz - 250 MHz1.25 GSa/s50 Mpts4NoYesYes
    DHO100070 MHz - 200 MHz4 GSa/s100 Mpts2/4NoYesNo
    MSO1000Z50 MHz - 200 MHz1 GSa/s24 Mpts4YesNoYes
    DHO80070 MHz - 100 MHz1.25 GSa/s25 Mpts2/4NoNoNo