Chapter 669 Wait for Your Comrade

At this point, Mr. Mo pointed to a component in the design diagram and said, "But the adjustment effect of this piezoelectric component has not been ideal. At first, we thought that the input and output characteristics of the piezoelectric component were not good and could not output accurately."

To put it simply, a piezoelectric element can precisely control the degree of deformation of the active surface of the element according to the input voltage.

The most common piezoelectric component is the piezoelectric ceramic buzzer, which controls the vibration of the buzzer according to the voltage and makes a buzzing sound.

From this point we can see that the piezoelectric element has a fast control speed. After all, in order for people to be able to hear it, the vibration frequency of the piezoelectric element must be at least 3k, which is 3000 times per second.

But things change when the control goal changes from deformation frequency to precise control of deformation amplitude.

The voltage input and deformation output must be in an accurately corresponding relationship. Otherwise, if the voltage is 1V, the deformation is 1mm this time and 1.2mm next time, which is a fantasy for the optical cavity length control of the laser gyroscope.

"So we found a piezoelectric component manufacturer and worked together to solve the problem of the input and output characteristics of piezoelectric ceramics."

Upon hearing the news, Gao Zhendong slapped his thigh and said, "Well done!"

Startled by Gao Zhendong's sudden excitement, Mr. Mo reacted with a wry smile: "The comrades in the production plant who cooperated with us are indeed good, but we are not so good. After the input and output characteristics problem was solved, we found that the biggest problem is not just this problem, but also that we can't accurately control the output voltage. If the voltage is not accurate, the deformation will naturally be inaccurate, and the optical resonant cavity length will not be good."

The wavelength of the laser is not much larger, and accordingly, the length adjustment of the optical resonant cavity is extremely small, which is why piezoelectric elements are used for adjustment and control.

This means that a sufficiently accurate output voltage is required to achieve an acceptable level of accuracy in adjusting the cavity length.

"We have tried many methods, but the resolution of the output voltage has not been ideal. We thought that Chief Engineer Gao is also very proficient in electronics, so we came to you to see if there is any solution."

Mr. Mo is also very frank. He has no other choice so he comes to you. It's not shameful to find the inventor of the laser.

Gao Zhendong thought about it and realized that you made the right choice to come to me for this matter.

"What voltage resolution can you achieve now? How many?"

"We have solved the problem of high-precision voltage source...but the resolution is only 6 bits, and it can't be improved any further."

To output a precise and adjustable voltage, two conditions are essential. One is a high-precision voltage source as a reference voltage, which determines the accuracy of the voltage. Otherwise, if you want 5V, the output will be 5.1V.

The other is a D/A with sufficient resolution, which determines the output resolution.

The so-called precision actually includes two aspects, precision and accuracy. The former refers to the degree of fineness, that is, resolution, and the latter refers to the degree of accuracy, that is, whether it is accurate or not.

Now they have solved the accuracy, but there is still a problem with the level of detail.

With a high-precision voltage source, its output characteristics are certain, but it does not mean that by reducing the voltage through the secondary circuit, a more practical resolution can be obtained when the number of bits of resolution is insufficient. The voltage reduction circuit will introduce new errors, and this also means that the controllable range becomes smaller.

Therefore, a high-resolution D/A is still required.

The 6 bits mentioned by Mr. Mo means that a voltage can be split into 64 parts at most for control, which is indeed a bit low.

However, the original research institute is indeed very powerful and solved all the problems that could be solved. They only came to Gao Zhendong for the last problem because they had no other solution.

This is easy to handle. Gao Zhendong smiled and said, "This is easy to handle. Is 8-bit accuracy enough?"

"8 bits? That's enough!" President Mo was very happy that Chief Engineer Gao directly asked "Is 8 bits enough?" instead of "How many bits are needed?" This means that Chief Engineer Gao has at least an 8-bit D/A or related technology.

Even though the number has only increased by 6 digits from 8 bits to 2 bits, in fact, the number of levels of voltage division has increased from 64 levels to 256 levels.

Gao Zhendong was happy: "You can go to the Military Communication Institute. They are developing an 8-bit weighted network decoder. It was originally used for voice coding, but at its core, it is an 8-bit digital-to-analog converter. You can go and have a look. It should be usable. If the number of bits is not enough, this kind of device is also relatively easy to expand. If 8 bits is not enough, then 10 bits, if 10 bits is not enough, then 12 bits... Anyway, your requirements for the conversion speed are not particularly high."

There is such a good thing? Mr. Mo was so happy.

"Really? Haha, that's great, great, we'll go ask the National Defense Committee for permission later."

After he finished speaking, he looked up and said, "Chief Engineer Gao, you don't know that with this one move, we have also solved half of our other problem."

The comrades in the original research institute are very interesting. They know all the problems, but they can't solve them. This is the case with optical cavity length control and frequency locking.

"Frequency locking uses dithering offset frequency. Just like what you said last time, dithering offset frequency looks simple, but how to dither is a practical engineering problem. Our current problem is that we can't accurately control the dithering frequency."

Mr. Mo was very happy and talked a lot.

"The current situation is that the frequency and amplitude of the jitter cannot be controlled very well, resulting in a large deviation between the compensation value of the frequency lock zone and the theoretical value." "We have also analyzed that the main problems we can see now are, first, the accuracy of digital-to-analog conversion is not enough, and second, the jitter control device is not good enough, and we cannot realize our control function under this volume."

Due to processing issues, the consistency between devices is not very good. Even though it is theoretically possible to use fixed optimal parameter jitter, in reality, this parameter of each gyroscope is still slightly different.

Gao Zhendong understood it as soon as he heard it. This jitter frequency still needs to be digitally controlled. The most troublesome parts of digital control for them are the control core and the digital-to-analog conversion.

After all, the core volume of a single unit of this thing is not large, with a scale of more than ten centimeters, and it is mainly occupied by optical devices. The external control system cannot be too large, otherwise it will lose half of its meaning.

The D/A device that Gao Zhendong had just instructed them to make could also solve half of the problem of the mechanical jitter frequency deviation system, so Engineer Mo was so happy.

In this way, even if the remaining problems cannot be solved, the worst that can happen is to hang up another DJS-60D, and it can be barely used. Although the advantage of small size is gone, at least other advantages are still retained, so it is not a loss.

But soon, Gao Zhendong told him what it meant to truly not lose out.

"As for the core control issue, I think this solution does not require too high computing power and speed. It just needs to have a flexible enough control method to take into account the calculation and output of data, right?"

"Yes, yes, yes, on this basis, the higher the output refresh rate, the better."

Under the premise of ensuring accuracy, the data refresh rate is theoretically as high as possible. For high-level gyro data users, this is equivalent to greatly increasing the sampling frequency, which means that the error will be smaller.

"Well... let's put it this way. For the control core issue, you guys can use DJS-61 first."

"DJS-61? How small is this?"

They knew about C6108 and DJS-61, but they had no idea how small they were, especially the DJS-61, which, in the photo, had a case with a power supply.

Gao Zhendong didn't say much, turned around, opened a drawer, took out three DJS-61 motherboards, and handed them to Mr. Mo.

Then, in front of everyone's stunned expressions, he opened another drawer, took out a matching number of C6108 and C6110, and handed them to them.

"You guys can use these first, are they enough?"

"That's enough, Mr. Gao. Is this all there is to the DJS-61?" In fact, he had another half sentence to say: How can you treat such an expensive thing like scratch paper?

Gao Zhendong nodded: "Yes, this thing is only this big, but don't underestimate it, it is at least 60 times faster than the DJS-2.5D!"

Mr. Mo then remembered that in the report on DJS-61, it was indeed mentioned that the speed of this machine was much higher than that of DJS-60D, but it did not say how much higher.

Mr. Mo calculated in his mind, haha...

"If that's the case, we don't need three DJS-60Ds. One is enough."

A complete gyroscope requires three laser gyroscopes to measure rotation in three-dimensional space. At the speed of DJS-60D, one computer must serve one to provide a sufficient data refresh rate. Even so, it is still impossible to take into account the control of mechanical jitter and frequency deviation.

The volume of three DJS-60Ds is still too large compared to the laser gyroscope.

But now with this thing that Chief Engineer Gao has come up with, one device can take care of the data solution and refresh of a laser gyroscope and various controls.

In this way, three DJS-61s can accomplish what three DJS-60Ds cannot. More importantly, the three formers combined are not as big as one latter!

This is of great significance to the practical application of laser gyroscope.

"Hey, Mr. Gao, we won't be polite then. So, put it away, put it away."

Mr. Mo's expression at this moment was very similar to the way we refused New Year's money from our elders when we were kids.

"You guys can use it first. We are working on some new things here. Maybe by next year, you will be able to use even smaller devices."

Gao Zhendong's words made Mr. Mo and the others fall into deep self-doubt.

No, I haven't finished one thing yet. Why are you making new things here as if it doesn't cost money or time, one after another, too many?

This made Mr. Mo even fall into a happy trouble. How about we wait? Otherwise, we will have to change the system connection and installation design, and even the program will have to be changed, which is very troublesome.

Chief Engineer Gao, please stop and wait for your comrades!
(End of this chapter)