A brief history of the development of oscilloscopes

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A brief history of the development of oscilloscopes [Copy link]

An oscilloscope is an electronic measuring instrument with a wide range of uses. It can transform invisible electrical signals into visible images, making it easier for people to study the changing processes of various electrical phenomena.

Some people think that a multimeter can conquer the world, so why spend time and energy to learn oscilloscopes? In a word, times have changed. The complexity and working frequency of today's electronic equipment systems are not comparable to those of a black and white TV or radio in the past. Learning to use an oscilloscope can definitely greatly reduce your maintenance workload and improve work efficiency.

And the application of oscilloscopes is not limited to the field of electronics. When equipped with appropriate sensors, oscilloscopes can measure various phenomena. For example, sensors for sound, mechanical stress, pressure, light or heat. Medical personnel can also use oscilloscopes to measure brain waves. Therefore, it is not an exaggeration to say that the oscilloscope is an electronic measuring instrument with a very wide range of uses.

Today we will take a brief look at the development history of oscilloscopes.

1. Draw the waveform by hand

The history of the oscilloscope dates back to the 1820s, when waveforms were recorded manually using a galvanometer coupled to a mechanical drawing system. The device consisted of a special single-contact commutator mounted on the shaft of a rotating rotor. The contact point could be moved around the rotor in accordance with a precise degree indicator scale, and the output appeared on the galvanometer, which was hand-drawn by the technician. Since this process was developed over several thousand wave cycles, only a very crude approximation of the waveform could be produced.

2. Mechanical automatic drawing of waveform

The first automatic oscilloscope used a galvanometer and pen to capture a waveform onto a continuously moving roll of paper. Because the frequency of the waveform was relatively high compared to the slow reaction time of mechanical parts, rather than drawing the waveform image directly, a waveform image was created by combining small segments of many different waveforms over a period of time. It would automatically charge a capacitor from the 100th wave and record it, with each subsequent charge of the capacitor starting from a point slightly further along the wave. Such waveform measurements were still averages of hundreds of wave cycles, but were more accurate than the hand-drawn waveform graphs that had preceded them.

3. Analog Oscilloscope

Analog oscilloscopes are mainly based on cathode ray tubes (CRTs). The electron beam is transmitted through the horizontal bias and vertical bias systems and hits the fluorescent material on the screen to display the waveform.

Cathode ray tubes for oscilloscopes:

1. Deflection voltage electrode

2. Electron gun

3. Electron beam

4. Focusing coil

5. The screen is coated with phosphorus coating

In the 1940s, the development of radar and television required waveform observation tools with good performance. Tektronix successfully developed a synchronous oscilloscope with a bandwidth of 10MHz, which is the basis of modern oscilloscopes.

Oscilloscope with synchronous sweep function

To improve the bandwidth of analog oscilloscopes, oscilloscope tubes, vertical amplification and horizontal scanning are required. To improve the bandwidth of digital oscilloscopes, it is only necessary to improve the performance of the front-end A/D converter, and there are no special requirements for oscilloscope tubes and scanning circuits. In addition, digital oscilloscopes can make full use of memory, storage and processing, as well as multiple triggering and pre-triggering capabilities. The 1980s became the world of digital oscilloscopes. Many manufacturers no longer produced analog oscilloscopes, and analog oscilloscopes gradually withdrew from the stage of history.

4. Digital Oscilloscope

Digital oscilloscopes are high-performance oscilloscopes made with a series of technologies such as data acquisition, A/D conversion, and software programming. Digital oscilloscopes generally support multi-level menus, which can provide users with a variety of choices and analysis functions. Some oscilloscopes can also provide storage to save and process waveforms. For oscilloscopes within a few hundred megabytes of bandwidth, domestic brands of oscilloscopes can currently compete with foreign brands in terms of performance, and have obvious cost-effectiveness advantages.

Digital oscilloscopes have most of the basic functions of analog oscilloscopes, such as basic waveform display function, xY working mode, basic triggering mode, etc. They also include trigger delay, input signal coupling mode, afterglow adjustment, calibration signal source output, etc.

Digital oscilloscopes have many more useful functions than analog oscilloscopes. The most common ones are auto-ranging, automatic measurement of various parameters, storage of waveforms and setting states, interface bus, display average level curve fitting (interpolation method), bandwidth high and low pass filtering, trigger working mode and trigger condition selection, cursor measurement, etc.

5. Touch Oscilloscope

In today's era, mankind is experiencing a digital revolution, with emerging technologies such as 5G, Internet of Things, big data, cloud computing, and artificial intelligence constantly evolving. Oscilloscopes are also undergoing a revolution. Compared with traditional buttons, the touch operation of smartphones has proven its efficiency. Oscilloscope manufacturers are also considering applying touch technology to oscilloscopes to replace traditional button and knob operation.

The backwardness of the original technical equipment and the slow improvement of the existing technology have caused headaches for engineers. The touch oscilloscope has brought engineers a new experience and greatly improved the original work efficiency. This new interactive method allows engineers to more quickly understand the problems in the entire product design, and use the test results to analyze, discover and solve problems without worrying about how to operate the oscilloscope.

maychang

"The history of the oscilloscope dates back to the 1820s"

To say so is too ignorant.

In 1800, a year before the beginning of the 19th century, Volta of Italy invented the battery. In 1820, Oersted of Denmark discovered the magnetic effect of electric current - a magnetic needle near a wire with electric current will be deflected by the current. In 1831, Faraday of Britain discovered the phenomenon of electromagnetic induction (that was already in the 1830s).

In the 1820s, it was impossible for a device to exist that consisted of a special single-contact commutator mounted on the rotating rotor shaft.