Understanding
and Using Them Effectively
Rémy Mallard
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3.3
3.3.4.4
3.4.3
3.4.5
4.4.3.1
4.4.3.2
4.4.3.3
4.4.3.5
4.5.5.1
4.5.5.2
4.7.2.1
4.7.2.2
5.2.3
6.2.2
6.5.1
6.7
6.7.1
6.7.2
6.7.3
6.7.3.3
6.7.4
6.7.4.1
6.7.4.2
6.7.4.3
6.7.5
6.7.5.1
6.7.5.2
6.7.5.3
6.9.3
6.9.6
6.9.12
8.1.6
8.1.7
8.1.8
8.2
Acknowledgements
To Elektor, for their continued trust.
To OVIO France, for the reliability of their after-sales service and for generously providing a license for serial data decoding for the Rigol DS1054Z oscilloscope purchased from them.
To Digital Vision, for their generous donation of Tektronix video oscilloscopes.
To PicoTech, for lending their differential probe.
To Édouard, for his careful proofreading and constructive feedback.
To Marie-Christiane, for her help with corrections and for her waterside home, which helped me better organise the chapters of this book.
And to myself, for indulging my own desires.
Chapter 1• Introduction
The oscilloscope is a fascinating device. Not only does it allow us to see the shape of signals invisible to the human eye, but it also teaches us a great deal about things that are difficult to imagine. For a long time, it was reserved for laboratories and after-sales service departments, but it is now available for a modest price. This makes it accessible even to beginners, who will find it increasingly difficult to come up with an excuse for not having one on their workbench.
I was 16 years old when I embarked on building an oscilloscope kit offered by the Electroradio Institute (Oscilloscope 70 with a DG7-32 cathode-ray tube). At that time, there was no talk of the Internet, but electronics, which was growing at an unstoppable pace, was heralded as the career of the future—electronics magazines were filled with entire pages of advertisements. The device I was about to become familiar with, with its round green screen staring at me like a doubtful eye, operated with vacuum tubes (valves) and high voltages. These high voltages could have frightened me or discouraged me. But I was no more scared than when I built my first stroboscope with its xenon flash tube, which also required a high voltage. I assembled the oscilloscope’s components, carefully following the instructions in the manual that came with it. And, I must admit, without understanding half or even a quarter of what I was doing. When I powered up the oscilloscope for the first time, not without some apprehension, a straight horizontal line appeared on the screen. I was proud of myself—the device had not exploded. However, my excitement was shortlived. When I applied a sinusoidal signal to the oscilloscope’s input, the displayed waveform became increasingly compressed on the right-hand side of the screen. The trace was bright and stable, but an oscilloscope worth its name should not distort a simple sine wave so badly. I immediately suspected my wiring—I must have made an error during assembly. So, I completely disassembled the device and rebuilt it from scratch. Unfortunately, after reassembly, the problem persisted exactly as before. That day, I felt deep disappointment, as I had no idea how the device worked and was completely unable to locate the problem. So, I set it aside and later gave it to a friend, who did not mind the fault (which I, of course, mentioned). He probably knew where to look...
This first experience with an oscilloscope disappointed me, but it did not discourage me in the slightest. After all, when I started in electronics, nine out of ten circuits I built did not work (and I like to remind people of that). Clearly, today, I would have been able to repair that stubborn oscilloscope myself—especially with the range of analogue and digital oscilloscopes that now fill my workshop...
I believe I can understand the frustration, questions, or even fear that a beginner may feel when faced with an oscilloscope, because I experienced them myself—even with a working device. To someone starting out, an oscilloscope may at first glance seem incredibly complex, both in its function and its use. This feeling is natural—there are a lot of adjustment knobs (and yet sometimes not enough—I will elaborate on this later). But this complexity is only apparent—and once the basics of how it works are understood, using the device becomes simple, and it quickly becomes indispensable.
Throughout this book, I have tried to put myself in the beginner’s shoes, setting aside the habits and reflexes I have developed over time. It is not for me to say whether I have succeeded in this challenge. But if we are to believe an old saying, it does not matter whether the arrow from the bow lands in the centre of the target—the important thing is that it flies. So, I hope that, like me, you will take off and continue your journey, no matter what obstacles stand in your way. I always wish my students to make as many mistakes as possible, and I wish the same for you. But please, follow the necessary safety precautions and heed the warnings scattered throughout this book. I would be genuinely saddened to hear that you had blown yourself up along with your workbench.
1.1 – What Is an Oscilloscope?
To fully understand everything discussed in this book, it is necessary to begin with a brief reminder of the structure of an oscilloscope.
An electrical current is the result of a phenomenon related to the movement of electrons. Due to the tiny size of electrons, we cannot rely on our eyes to follow their motion. This is incredibly frustrating, especially for those with a keen interest in atomic physics. Fortunately, the day arrived (not so long ago, as it happened in the twentieth century) when ingenious individuals developed an electronic device that allowed, through a cathode-ray screen, the examination of the shape of an electrical voltage—or the electric current that this voltage generated—within a circuit. The oscilloscope was born.
An oscilloscope is simply a device that enables the visualisation of the evolution of an electrical signal over time on a screen. It can also be used to display a quantity other than an electrical signal (such as air pressure, temperature, or current), as long as this quantity is first converted into a voltage. This makes oscilloscopes relevant across electrical, electronic, and mechanical fields, as well as in both analogue and digital domains. When starting out in electronics, people usually associate oscilloscopes with electronics engineers. However, the scope of an oscilloscope’s applications is vast—both air surveillance radar and the electron microscope are derivatives of oscilloscope technology. The signal to be observed is displayed on a screen in the form of a bright trace, known as an oscillogram, as shown in Figure 1.1.a.
Figure 1.1.a – Oscilloscope waveform (oscillogram) displaying an alternating triangular signal.
The display of the signal to be observed is in two dimensions: height (vertical scale) and width (horizontal scale). The screen is divided into multiple equally spaced sections, with each vertical or horizontal segment of the grid called a division (div). Dividing the screen into smaller sections makes it easier to read the “width” and “height” parameters of the displayed signal. In Figure 1.1.b, the screen is divided into eight equal vertical sections and ten equal horizontal sections.
Figure 1.1.b – Oscilloscope screen with horizontal and vertical divisions. The division markers form a grid, also called a graticule. The number of divisions may vary between oscilloscopes.
Note: The number of vertical and horizontal divisions may vary depending on the oscilloscope model.
The vertical scale represents the amplitude of the electrical signal in volts per division (V/div). As we will see later (in the chapter on oscilloscope configuration), the V/div unit can express millivolts, volts, or even tens of volts. In other words, the spacing between two vertical divisions does not always correspond to “1 V per division.”
The horizontal scale represents the time interval of the observed signal, expressed in seconds per division (s/div). This unit (s/div) can represent nanoseconds, microseconds, milliseconds, seconds, or even tens of seconds. In other words, the spacing between two horizontal divisions does not always correspond to “1 second per division.”
Notes:
• On early oscilloscopes, divisions were marked as “cm”, and the user manual specified sensitivity as “per cm” (e.g., 100 μV/cm to 20 V/cm for the HP 140A oscilloscope). Each division could correspond to 1 cm, but this varied (0.72 cm per division on the HP 1744A, for example). Over time, the term “div” (division) became standard, as “cm” had to refer specifically to 1 cm, which not all manufacturers adhered to.
• A classic oscilloscope typically shows how a signal changes over time. However, a dual-input oscilloscope can also display how one signal evolves relative to another (such as in signal composition, Lissajous figures, and XY mode, which will be discussed later).
• An oscilloscope is primarily a diagnostic tool rather than a measurement instrument. However, if sufficiently precise and used within its known limitations, it can be used for measurements. In practice, an inspection can sometimes serve as a low-precision measurement. For hobbyist use, a measurement accuracy of ±5% is generally sufficient.
Electrical signals exist both in nature and in a technician’s laboratory. These signals vary widely in their characteristics: low or high amplitude, low or high frequency, simple or complex waveform. For example, the electrical signals from the human body, measured using an electrocardiogram (ECG) or electroencephalogram (EEG) with electrodes and conductive gel, are vastly different from the 230 V mains voltage supplied by an electricity provider such as EDF/ERDF. Yet, both are electrical signals that evolve over time, each in their own way, and both can be displayed on an oscilloscope (see Figure 1.1.c).
Figure 1.1.c – Electrical pulses linked to human heart activity can be observed on an oscilloscope. Similarly, the alternating voltage supplied by a domestic electricity provider can also be displayed. In both cases, an electrical signal evolving over time is visible— whether at a slow speed (detectable by the human eye) or at high speed (too fast for the eye to follow).
For an oscilloscope to correctly display these different types of signals, it must have settings that allow it to adapt accordingly. First, it requires a sensitivity adjustment, which enables the amplification or attenuation of the signal to be visualised. When this setting is properly adjusted and the bright trace is positioned correctly on the vertical axis of the screen, it becomes possible to observe low-amplitude signals (for example, a few millivolts) or high-amplitude signals (several tens of volts) with precision. Second, the oscilloscope must have a sweep speed adjustment, which determines the ideal placement of the bright trace along the horizontal axis of the screen. With these two adjustments, the oscilloscope is almost ready to accurately display how various signals evolve, whether they have a low or high frequency. We will, of course, explore these two settings—height/amplitude and width/speed—in greater detail later, as they are based on fundamental concepts.
The oscilloscope is a frequently used device in electronics because it allows the observation of electrical signals at different points in a circuit—something a simple multimeter cannot
do. It is the ideal tool for anyone designing or troubleshooting a circuit. It is no coincidence that the oscilloscope has earned the nickname “the electronic engineer’s eye.”
Note: Some oscilloscopes, in addition to serving as signal visualisers, can also function as signal generators. We will later explore how such an option or extension can be useful.
1.2 – Basic Operation of an Analogue Oscilloscope
A basic analogue oscilloscope is relatively simple to construct. In its most simplified form, it consists of:
• a cathode-ray tube for display,
• a voltage amplification stage (to visualise low-amplitude signals),
• an oscillator circuit that generates a ramp-shaped (sawtooth) signal.
This chapter explains how the oscilloscope functions. It does not cover how to perform measurements—that will be explained in the chapters Basic Measurements and Advanced Measurements.
1.2.1 – General Block Diagram
The simplified block diagram in Figure 1.2.1.a illustrates the functional blocks (subsystems) that form the basis of an analogue oscilloscope.
Figure 1.2.1.a – General block diagram of an analogue oscilloscope, showing its voltage amplifier, synchronisation system, and time base, which generates a periodic ramp signal.
The input amplifier ensures that the signal applied to the cathode-ray tube has a sufficient amplitude. The tube itself operates with (and requires) high voltages. The ramp generator (the official supplier of sawtooth signals) determines where on the screen the oscilloscope should display the waveform at any given moment. This generator can produce ramp signals in different ways:
• Continuously, one after the other, without considering the nature of the signal being displayed. This mode is known as AUTOMATIC or FREE-RUNNING mode.
• Synchronised with the observed signal. In this case, it is called NORMAL mode, which is the most commonly used mode in standard operation.
• Synchronised with an external signal, which may have a different waveform from the one being visualised.
Depending on the selected mode, the displayed trace may appear either stable or unstable. These different modes will be explained in the Oscilloscope Configuration chapter, under the Triggering Modes section.
To summarise:
The vertical position of the spot on the screen (the bright point used to draw the waveform) depends on the amplitude of the input signal and the settings of the voltage amplifier. The horizontal position of the spot depends on the ramp (sawtooth) signal produced by the time base generator.
1.2.2 – Amplifiers
The signal to be visualised rarely has a sufficient amplitude to cause a significant deflection of the electron beam in the cathode-ray tube. If it were applied directly to the vertical deflection plates, the bright trace would either remain stationary or deviate only slightly from its central position. To accommodate voltage sources with widely varying amplitudes, the oscilloscope is equipped with a voltage amplifier, preceded by a user-adjustable attenuator. With these two elements (attenuator and amplifier), it is possible to obtain a “normal and sufficient” voltage to drive the vertical deflection plates of the cathode-ray tube, regardless of whether the input signal has an amplitude of a few millivolts or several volts.
The oscilloscope’s input stage also ensures a fixed and high input impedance, typically 1 MΩ in parallel with a capacitance of a few or several tens of picofarads (pF). As we will soon see, these two parameters—”input impedance” and “input capacitance”—play a crucial role in the accuracy of a measurement.
Note: The author once had the opportunity to work with a technician who admitted to disconnecting the input amplifier of his oscilloscope in order to inject a high-frequency (HF) signal directly onto the vertical deflection plates (the HF signal came from a probe monitoring the output of a TV transmitter). He claimed this bypassed the bandwidth limitation of the input amplifier. The displayed signal was unstable, but that did not concern him. After “calibrating” his modified oscilloscope, this colleague could determine whether the amplitude of the HF signal was correct or not. This reminded the author of a modification he had made to a black-and-white television, converting it into a giant oscilloscope—a topic discussed in Appendix 4.
1.2.3
– Time Base and Sweep
The amount of horizontal deflection (degree of horizontal displacement) of the electron beam in the cathode-ray tube is directly related to the value of the voltage applied to the horizontal deflection plates. The action of automatically moving the bright spot from left to right across the screen is called sweep. Without a sweep function, the electron beam
remains undisturbed in its straight-line trajectory within the tube, and the oscilloscope cannot display any trace along the horizontal plane (although it could still display one in the vertical plane). At most, in such a case, it would show a static bright dot of little interest. Additionally, it presents a potential burn hazard to the fluorescent surface of the screen, as illustrated in Figure 1.2.3.a.
Figure 1.2.3.a – If the electron beam is not deflected either vertically (no voltage applied to the oscilloscope input) or horizontally (no sweep), a fixed bright spot appears at the centre of the screen. This dot is of little use and poses a risk of burning the fluorescent coating.
Sweep (horizontal deflection) is achieved by applying a rising ramp-shaped voltage to the horizontal deflection plates, starting at a minimum value and increasing to a maximum. When the horizontal deflection plates receive the minimum voltage, the electron beam is deflected to the left, and the bright spot appears at the far-left side of the screen (as far left as possible while remaining visible). When the horizontal deflection plates receive the maximum voltage, the electron beam is deflected to the right, and the bright spot moves to the far-right side of the screen (again, while remaining visible). By varying the horizontal deflection voltage smoothly and continuously (in a rising linear ramp pattern), the bright spot moves from left to right at a constant speed.
Note: Once the spot moves quickly enough and due to the persistence of the cathoderay tube, the moving dot is no longer perceived as a point but rather as a continuous bright trace.
Once the bright spot reaches the far-right side of the screen, it can quickly return to the left. This is done by abruptly lowering the horizontal deflection voltage. At this moment, the electron beam is turned off to prevent the return movement from being visible. If, immediately after this, the horizontal deflection voltage resumes its linear increase, the resulting signal takes the shape of a sawtooth wave, and the bright spot once again moves across the screen from left to right, as shown in Figure 1.2.3.b. This continuous and uninterrupted sweep cycle, where the spot repeatedly moves back and forth across the screen, is called automatic mode (we will see in the chapter on triggering modes that the term AUTO can have multiple meanings).
Figure 1.2.3.b – In “automatic” mode, the voltage applied to the horizontal deflection plates of the oscilloscope’s cathode-ray tube increases linearly from a minimum to a maximum, then abruptly drops back to the minimum before restarting another linear rise. This type of signal, consisting of a series of rising ramps, is called a sawtooth wave due to its distinctive shape.
The speed at which the bright spot moves (the time it takes for the sawtooth wave to rise from its minimum to maximum value) is determined by the time base setting. If the user sets the time base to 10 ms/div (10 milliseconds per division) and the screen is divided into 10 equal horizontal divisions, this means the bright spot will take 100 ms to travel across the entire screen (10 ms × 10 divisions). If the same oscilloscope is set to 100 µs/ div (100 microseconds per division), the bright spot will take 1 ms to traverse the entire screen (100 µs × 10 divisions).
Key takeaway: The duration represented by a single horizontal division is not always the same, as it depends on the time base setting adjusted by the user. On a basic analogue oscilloscope (without embedded computing), a waveform can be displayed, but the current time base value is not shown on-screen. For this reason, the user must remember the selected time base setting. On modern devices, however, the time base value is displayed (or can be displayed) directly on the screen.
The movement of the spot from left to right can be slow or fast, depending on the user’s preference. If it is sufficiently fast, the trace appears as a fixed line, as seen in Figure 1.2.3.c.
Figure 1.2.3.c – Once scanning is activated, the spot (bright point) moves from left to right at a speed that depends on the time base setting. If the spot moves quickly and repeatedly (automatic mode), a “fixed” line appears instead of a moving point.
Note: When the scanning speed is moderately slow, a type of flickering may be observed, which can be disturbing to the eye. Some devices allow this discomfort to be reduced with a trace persistence setting, which, when properly adjusted, keeps the previous trace on the screen until the next one appears. This setting also allows for a more comfortable view of occasional events, which would otherwise appear less bright than the rest. This issue does not exist with digital oscilloscopes, whose screens are free from afterglow (although this effect can be simulated with a software persistence option).
When an oscilloscope is turned on, assuming it is set to default settings, there is a high likelihood that a bright line will appear. This confirms that the scanning function is active. If a constant DC voltage is then applied to the oscilloscope’s input (for example, from a battery), the bright trace moves vertically (upwards or downwards, depending on the polarity of the voltage source) and remains in its new position as long as the voltage is present and remains unchanged. The distance of the trace from the centre of the screen depends on the amplitude of the voltage applied to the oscilloscope input, as well as the vertical scale setting. At this stage, the adjustment may not allow significant movement of the trace, or conversely, the trace may move completely off the screen. This will be discussed in more detail later.
If the voltage applied to the oscilloscope is positive relative to ground, the bright trace moves upwards on the screen, as shown in Figure 1.2.3.d.
Figure 1.2.3.d – If a positive DC voltage is applied to the oscilloscope input, the bright line shifts upwards on the screen. The degree of shift from the centre depends on the input voltage and the vertical scale setting (volts per division).
If the voltage is negative relative to ground, the bright trace moves downwards on the screen, as seen in Figure 1.2.3.e. Again, the displacement of the trace from the centre depends on the voltage applied to the oscilloscope input and the vertical scale setting.
Figure 1.2.3.e – If a negative DC voltage is applied to the oscilloscope input, the bright line shifts downwards on the screen. The degree of shift from the centre depends on the input voltage and the vertical scale setting.
For DC voltage observation, the time base setting is not particularly important since the spot remains at a fixed vertical position. However, to observe a signal that varies over time, such as an AC signal, the time base must be properly adjusted. The ideal setting depends on the frequency of the input signal. The higher the frequency, the lower the time base value should be. This is logical: over the same time interval, a high-frequency signal contains more cycles (periodic variations) than a low-frequency signal. The objective is usually to display one or more full periods of the signal. Later, a simple formula will be introduced to help determine an approximate time base value based on the frequency of the observed signal (though this is only useful if the signal’s frequency is already known).
Note: The concept of period applies to a signal with repetitive variation patterns. Some signals, whose amplitude changes over time, are not periodic. An example is white noise, which is inherently random. Likewise, digital data transmitted over a serial UART/RS-232 or USB link cannot be considered a periodic signal despite frequent state changes.
If a time base that is too short is used for a time-dependent signal, only part of the signal will be visible, and important details may be missed. Figure 1.2.3.f illustrates such a case, where the time base is too short compared to the observed signal’s frequency.
Figure 1.2.3.f – If the time base value is too small relative to the signal’s evolution speed, important details may be missed. Here, a 50 Hz sine wave is displayed with a time base of 1 ms/div (12 ms across the full screen width, as there are 12 horizontal divisions). While this setting does not allow for viewing a complete period of the signal, it does provide a “zoom” on a specific section, which may be useful.
In Figure 1.2.3.f, the signal is a 50 Hz sine wave. If the goal was to display at least one full period of the signal, the setting is incorrect. However, if the objective was to zoom in on a specific region, such as where the sine wave crosses 0 V, then the chosen time base is appropriate.
Key takeaway: The time base setting primarily depends on the signal’s frequency, but it also depends on what needs to be visualised (a full signal overview or a zoomed-in section).
If the same 50 Hz sine wave is observed with a time base that is too large, too much information is displayed at once, making it difficult or impossible to discern details. This issue is illustrated in Figure 1.2.3.g (though with a digital oscilloscope with a zoom function, this would not be a problem, as it allows magnifying the acquired trace afterward).
Figure 1.2.3.g – If the time base value is too large relative to the signal’s frequency, too much information is displayed at once, making details difficult to distinguish. Here, a 50 Hz sine wave is visualised with a time base of 500 ms/ div (6 s across the full screen width, as there are 12 divisions). The signal is so compressed that its shape is barely visible.
For observing a few periods of a repetitive signal, it is best to select a time base value that matches the signal’s period. Figure 1.2.3.h provides an example, where the time base is set to 5 ms/div (60 ms across the full screen width).
Figure 1.2.3.h – With an appropriately chosen time base, the observed signal is displayed with an ideal level of detail. Here, a 50 Hz signal is visualised with a time base of 5 ms/ div (60 ms across the full screen width). Since a 50 Hz frequency corresponds to a period of 20 ms, three complete periods are visible (3 × 20 ms = 60 ms).
In the Oscilloscope Usage chapter, we will explore how to properly select the time base value based on the signal’s frequency and period, assuming these values are known. However, we already understand that to view at least one complete period of a signal,
the oscilloscope’s display window (linked to the time base setting) must be equal to or greater than the signal’s period. Often, the user will simply turn the dial until the displayed waveform appears correct. This approach, while not technically precise, is practical and efficient.
Now, let’s discuss the stability of the displayed waveform. A continuously running sawtoothcontrolled sweep may seem like a great idea, but in practice, it presents challenges. Why?
Imagine observing a 1 kHz sine wave. Since its period is 1 ms (T = 1/F), the pattern repeats every millisecond. If the oscilloscope’s time base is set to 200 µs/div, covering 2.4 ms across the screen, the waveform may not always start at the same point in each cycle, leading to an unreadable overlapping display. This issue is illustrated in Figure 1.2.3.i.
Figure 1.2.3.i – A 1000 Hz sine wave displayed in automatic mode without signal synchronisation. The overlapping traces create a chaotic display, making it impossible to extract useful information.
To explain this in more detail, let us examine the three screens in Figure 1.2.3.j. These three screens, placed side by side, show three consecutive traces that would be recorded one after another, without considering the signal to be observed.
Figure 1.2.3.j – These three screens represent three consecutive snapshots, recorded without considering the voltage of the observed signal, which would determine when the trace display should begin. Each trace (each sweep) starts at a different point in the repetitive signal pattern.
The three adjacent screens in Figure 1.2.3.j represent these snapshots from a temporal perspective on a horizontal timeline (ignoring the dead time between traces). Now, let us reposition these three screens vertically, as shown in Figure 1.2.3.k. This better illustrates the disruptive effect of these uncontrolled overlaps.
Figure 1.2.3.k – If the three snapshots (several consecutive sweeps placed on the same screen) are superimposed, the traces do not align properly, making the final display unusable. This issue was also highlighted in Figure 1.2.3.i.
The issue here is clear—it arises because each trace does not start at the same point in the repetitive pattern. This can be resolved using a simple method known as synchronised triggering. The purpose of triggering is to prevent the sweep from running freely and automatically with a continuous sawtooth control signal, instead ensuring that the sweep begins at a precise moment that aligns with the signal being observed. By doing so, each new trace starts at a defined reference point within the signal, such as when it crosses zero volts. Thus, with our 1 kHz sine wave, we can ensure that each trace (each sweep) begins precisely when:
• The voltage is either rising or falling (i.e., the slope or direction of the observed signal) and
• The voltage reaches a specific value (trigger threshold).
Applying this principle of oscilloscope trace synchronisation to the observed signal results in a stable display, as shown in Figure 1.2.3.l.
Figure 1.2.3.l – If the sweep is synchronised with the movements of the observed signal, each new trace starts at the same point in the signal’s period. This ensures a stable display, where the traces no longer overlap chaotically.
This time, the patterns traced by the spot are superimposed from one sweep to the next, allowing the observer to clearly see the characteristic shape of the alternating signal in full detail.
Note: The superimposition of traces may give the impression that only one trace is visible at a time. However, multiple traces are present. The thickness of the displayed trace, resulting from multiple overlaid traces, may vary depending on the stability and purity of the observed signal. An unstable signal (either in time or amplitude) produces a thicker and less precise trace. Later, we will see that trace persistence can provide useful insights into the “validity” of a signal.
A simple synchronised trigger is effective for basic signal shapes, but it is not a universal solution for all types of signals. Stability issues may arise again with certain complex signals, such as amplitude-modulated signals containing both high-frequency carrier waves and low-frequency modulating waves, or even digital signals on a data bus. In such cases, when exactly should the sweep begin? For such signals, an analogue oscilloscope will struggle to produce a usable display (unless it includes a trace memory), whereas a digital oscilloscope (which inherently possesses some memory capacity) will handle the situation more effectively.
We have discussed triggering in broad terms without delving too deeply into details, as there are actually several triggering modes, which will be covered in a dedicated chapter. Similarly, we have seen that an oscilloscope allows the visualisation of a periodic signal, but we have not yet addressed how to determine its key characteristics, such as amplitude and frequency. This will also be explored in detail in a later chapter.
