Digging back to the prehistoric era of oscilloscopes, why did China not have high-end oscilloscopes?

As the most basic comprehensive instrument in the electrical measurement industry, the oscilloscope is designed and manufactured in a wide range of fields, from semiconductors to special materials, from machining to electronic design. This requires a strong and complete industrial system as support. But the Soviet Union had all of these in its early days? Why didn't the Soviet Union succeed? In fact, the market is also very critical. Relying solely on national power, it may be possible to concentrate on solving a problem in a short period of time, and then invest in the treatment of other problems. Some things cannot be studied in depth continuously. Only when the continuous demand of the market continues to stimulate technological progress, just like war, can technology have a huge leap. In addition, the progress of some other technologies, such as electronic computers, is also complementary to the development of instruments, which has also brought about a comprehensive change in thinking.

Regarding the specific technologies related to oscilloscopes, before the 1960s, generally speaking, the gap between China and foreign countries was not particularly large, because everyone used electron tubes, which only had certain requirements for industrial machinery and equipment, mainly stamping and welding, etc. In addition, the special cathode coating material of the electron tube also had a crucial impact on the performance, but all of this was not out of reach. In addition, the bandwidth of oscilloscopes during this period usually did not exceed 40MHz, which was indeed not particularly difficult. At this stage, we did not have much gap in technical reserves, mainly because the demand was not too much, resulting in the product being somewhat backward in terms of process and structure.
  Figure: Part of the TEK 511 oscilloscope. You can see that there are many text prompts printed on the bottom plate, which are quite detailed.

By the way, the manufacturing process of this era, because the electron tube itself is large in size, and most of the components used are also large with high voltage and high current, both domestic and foreign components are installed in this way, that is, the components are installed on the bracket, and then connected with wires. This method is commonly known as scaffolding welding in China.

In the mid-1960s, some semiconductor devices began to gradually replace the position of electron tubes, and the bandwidth of oscilloscopes began to reach 100MHz. During this period, the application of electronic computers also began to be gradually promoted, which led to more demand for oscilloscopes. At this time (around 1965), HP also released the HP-IB bus, which was later standardized in the 1970s as IEEE488, also known as GPIB. Through this control bus, computers can control the operation of electronic instruments, collect instrument data and analyze them. This has brought our use and understanding of data to a new level, and at the same time has given rise to the concept of automated measurement systems, which has brought higher efficiency and better accuracy. At this time, there was still not much progress in China. High-bandwidth oscilloscopes put forward very high requirements for processing technology and design, and there were not many electronic computers in the country.
  
As transistors reduced the size and power consumption, printed circuit board technology began to be promoted. Through PCB boards, electronic components can be installed quickly and orderly, while reducing parasitic parameters. Therefore, the manufacturing industry technology of circuit boards also developed synchronously.

http s://www.youtube.com/watch?v=7weZ0TNRcuw&index=14&list=PLRkbT1iOCUUl9fI55OYJEWu-

This video was filmed by Tektronix in 1969 about the entire process of PCB design and production. You can see how it was done at that time. As a reminder, the elegant curves in the picture above are all drawn manually.
  
The picture comes from a DIY by an old predecessor, but the domestic PCB at that time was basically like this. It looks much rougher. The main method is to punch holes and rivets at the mounting points of each component, and then weld them on the rivets, and connect them on the back. This process is inefficient and the mounting density is also low. These auxiliary industries also seriously affect the improvement of the integration of instruments.

Entering the 1970s. The microwave semiconductor technology of the Americans has made great progress, and the microelectronic integrated circuit technology has been changing with each passing day. During this period, the bandwidth of conventional oscilloscopes reached 350MHz, and special oscilloscopes could reach 1GHz. At the same time, the further development of semiconductor technology has made the oscilloscope completely programmable and can also perform digital acquisition. For example, analog oscilloscopes of the same era already have microprocessors, which can read the measurement parameters intuitively on the fluorescent screen, and can pass the parameters and waveforms to the computer. It was not until decades later that domestic analog oscilloscopes began to have this capability. At this time, our semiconductor industry has stagnated and can only produce ordinary logic gate circuits. Of course, CPUs such as 8086 have also been copied, but think about it, 1. No one will use it, 2. The cost is frighteningly high, and 3. Using these things to make measuring instruments greatly increases the cost and complexity of the instruments, but there are not enough computers to match them. At this time, the measurement needs are mainly met by imports (Sino-US relations are still okay). In this era, due to the needs of instruments and the military, the Americans began to make 4-layer circuit boards, and used early computers for EDA-assisted circuit design,
  
such as... If you don't compare, you really don't know how big the gap is.

The 1980s was the era of the rise of PC and Subor. In this era, thanks to the demand for ultra-large-scale circuits in many industries, oscilloscopes also benefited from it and entered the digital age. Due to special needs such as radar, gallium arsenide semiconductor technology grew rapidly and was also used in radio frequency measuring instruments such as network analyzers and spectrum analyzers. These technical preparations in other fields paved the way for high-performance digital oscilloscopes. However, due to the scarcity of related industries in China, a huge technological gap appeared at this time, and it has not been caught up until today. If you are interested, you can take a look at the various American Subor in the 1980s, which have various CPUs, such as Z80, MC6800, MC68000, 6502, etc. It has to be said that the market played a huge role. Due to the manufacture of these consumer electronic products, there is naturally a huge demand for electrical measuring instruments. During this period, the density of components was greatly improved, which also promoted the maturity of SMD surface mounting technology, which means that the integration, stability and production speed of circuits have been greatly improved.

In the early 1990s, with the increasing complexity of computers and various network systems, higher requirements were put forward for measuring instruments. At this time, high-performance digital oscilloscopes represented by the HP54600 series and the Tektronix TDS500 series came on the scene. After a long period of technical accumulation, the digital oscilloscopes at this time integrated advanced semiconductor technologies, such as microcomputers, DSP, CPLD, and specially designed ASICs and ADCs representing core technologies, trigger controllers, etc. In terms of software, it is also a collection of various advanced measurement algorithms. It can be said that no matter from which aspect, our gap in that era was not a little bit. After all, the parts of a 286 cannot be completely localized, so how can we talk about more advanced oscilloscopes?

So the question from the author is actually very broad in my opinion, and it involves multiple fields. Although from the perspective of an instrument itself, it may be mainly limited to a few key components. However, to make these things is by no means to organize a few national technical research and development to get the corresponding results. It is the product of long-term accumulation and progress, and the crystallization of wisdom. At the same time, it is also the inevitable result of adapting to the development of the times and market demand.

Below, we will take a brief look at the history of oscilloscope development to gain a deeper understanding of the concept of technology accumulation. We will also take a look at the ideas of our predecessors.

In ancient times (before the 1990s), HP had not yet been split up, so it also produced electrical measuring instruments, and made its fortune with instruments. After the split, electrical measuring and biochemical measuring was called Agilent (now electrical measuring was split up again and called Keysight). Semiconductor technology was called Avago. Similarly, Tektronix once had MAXTEK, which designed and manufactured special customized parts required for its own instruments.

-01: ​​Prehistoric
  
Oscilloscope history | Wikiwand

The origin of electronic oscilloscopes is not easy to verify, so the prehistoric era is divided by the operating characteristics of the oscilloscope. Today, we probably use the edge trigger mode most often, and even often think that it is part of the basic functions of the oscilloscope. In fact, before the TEK 511, oscilloscopes did not have triggering capabilities. In order to display the waveform stably, the oscilloscope at this time used a technology called synchronous scanning. The oscilloscope scans freely at a fixed frequency to display the waveform. In order to stabilize the waveform, it also has a simple comparator control to determine when to start scanning. However, due to the uncertainty of the scanning time, the time axis of the oscilloscope tube is also unstable. This oscilloscope cannot perform accurate time measurements and cannot observe non-periodic signals.