"Oh? Let's hear it. Zhou Jianhua nodded and replied.

"There is a communication device, which involves both analog signals and pulse signals, both high-frequency signals and low-frequency signals, because of its portability requirements, this equipment is designed to be very compact, and then, there are a lot of electromagnetic compatibility problems......" Cai Shangzi said carefully:

"Hmm...... Truth be told, this is a problem that my research group is currently trying to solve. We have taken a variety of signal shielding and isolation measures, but we still can't solve all the problems of mutual interference, I don't know what you think about this situation......"

"Huh...... You can't intuitively see the device you're talking about, and you're talking so vaguely...... Where do I start? Zhou Jianhua shook his head with a smile and said:

"Hehe, I'm sorry, it's a bit hard for you...... But we have discipline and can't ......," Cai Shang replied with an embarrassed smile.

"Hmmm! I understand......" Zhou Jianhua said with a slight sigh:

"Well, in view of the equipment situation you described, I will talk about some of the technical methods I can think of one by one, and see if there is anything that can be supplemented by the various measures you have done."

"Hmmm! That's the best! Just do what you say, you say I'll listen! Hehe...... Jianhua, it's going to take a lot of effort for you. Cai Shang replied with an apologetic expression.

"Well, it's fine! Let's say the same. Zhou Jianhua replied:

"First of all, the power part, your equipment is definitely indispensable. As a portable device, it must have a DC power supply, can your device be plugged in and charged? ”

"Yes!" Cai Shang replied.

"First of all, the power supply and high-current wires should be close to the bottom of the box of the portable communication equipment, and the wiring should be routed along the corners." Zhou Jianhua said, pausing and looking at Cai Shang.

"Hmm!" Cai Shang nodded in confirmation.

"Switching power supplies – if you use them – need to be isolated to prevent radiated emissions, filters should be π or T-type to suppress wide-band noise, and ferromagnet materials should be used to suppress RF noise." Zhou Jianhua said, glancing at Cai Shang again.

"Hmm!" Cai Shang nodded again.

"Isolated grounding must be considered at both ends of the power line to avoid common impedance coupling in the ground loop and coupling noise to the signal line."

"Hmm!"

"The power and signal lines should be isolated or separately as much as possible. The power transformer should be isolated, and the shell should be well grounded. ”

"Hmm!"

"Stranded wires are recommended for single-phase AC control wires, and stranded wires are recommended for DC conductors. Avoid connecting the power supply to the same connector as the signal cable. ”

"Oh? DC wires also use stranded wires for wiring? Cai Shang asked puzzled.

"Yes! Although it is a DC wire, it can also be loaded by an external AC signal, so it is best to use stranded wires for wiring. Zhou Jianhua explained.

"Oh...... What a shame! Wait a minute......"

Cai Shang nodded, quickly took out a small notebook from his pocket and wrote it down, then raised his head and said happily to Zhou Jianhua:

"Thank you! Let's move on! ”

"Hmm...... That's all I'd like to get right now about the power supply, but now let's talk about the isolation and shielding measures for the signal lines. ”

"What a shame!" Cai Shang nodded and replied excitedly.

Zhou Jianhua continued to analyze with Cai Shang one by one:

"Signal input and output lines should not be lined up together to avoid mutual interference......"

……

Cai Xueying saw that her brother and Zhou Jianhua were discussing some technical issues that she didn't understand, and she didn't understand it, and it was inconvenient to disturb her, and she was bored, when she suddenly saw her father pushing a bicycle into the hospital, she quietly walked out of the living room, walked forward and said while helping her father park his bicycle:

"Dad, Zhou Jianhua has come to pay you a New Year's greeting."

"Oh?! Hehe...... How did this busy man come over today? Cai Zhongming immediately looked happy.

"He just came over after work and brought you two bottles of good wine!" Cai Xueying replied.

"Really?! Go and ask your mom to stir-fry two more good dishes! It just so happens that your brother is also here, so let's talk about it today! Cai Zhongming happily commanded.

"You don't need to tell me, my mother is already frying." Cai Xueying also replied happily. Seeing that Cai Zhongming was going to the living room, Cai Xueying hurriedly stopped Cai Zhongming:

"Dad, Zhou Jianhua is talking to his brother about skills, the things Zhou Jianhua said seem to be very important to my brother, you better don't disturb them first, let them finish chatting quickly, let's eat again." Zhou Jianhua is so busy every day, let him finish eating early or rush back to rest early. ”

"Oh! That's good! Then I'll go to the kitchen first. Cai Zhongming responded, and was just about to walk to the kitchen, when he suddenly turned his head to look at Cai Xueying, and asked jokingly:

"Huh? That's not right! Your dad and I just came back, why don't you care about me and let me rest early, but you care about others? ”

"I ...... Didn't you say he's a busy man all the time? Let him go back and rest early, can't you rest early? Cai Xueying hurriedly argued, but her face turned red.

"Huh...... Okay, I'll go to the kitchen first, you go and keep an eye on them, and as soon as you're done talking, call them to dinner! Cai Zhongming said and went to the kitchen.

Cai Xueying returned to the living room, and saw that the two of them hadn't finished chatting, so she sat at the table with her head propped up with her hands, and patiently watched Zhou Jianhua and her brother concentrate on analyzing the technical problem, and waited for a while before Zhou Jianhua was almost done, and his brother's notebook was full of pages.

"Brother Cai Shang, that's all I can think of, I hope it can be useful to you." Zhou Jianhua said after the most reluctance.

"It definitely works!" Cai Shang said excitedly:

"Brother Jianhua! You've done me a great favor today! These questions have been bothering our group for many days, but I am glad to have met you today! I'm leaving tomorrow, and if you come any later, I'll miss out on a good opportunity! Thank you so much today! ”

"Hehe, Brother Cai Shang, you don't have to be polite, it is also my wish to contribute to the country." Zhou Jianhua replied with a smile.

"Two scholars, have you finished talking?" Cai Xueying saw that the two were finally chatting, sighed, and quickly interjected:

"Mom and Dad are waiting for you two college scholars to eat!"

"Hehe, I'm sorry, Brother Jianhua, let you go hungry and talk to me so much, let's hurry up and eat!" Cai Shang also greeted warmly.

"Brother! When did you take in a brother? Did you get my permission? Cai Xueying protested angrily.

"Ah...... Why...... I want your permission to recognize a brother? Cai Shang asked inexplicably.

"He has already been accepted by me first, if you want to accept it, you have to get my permission first!" Cai Xueying glanced at Cai Shang savagely, and replied proudly.

Cai Xueying is 5 years younger than Cai Shang, Cai Shang has loved his sister since he was a child, and let his sister in everything, the relationship between the brother and sister has always been very good, in front of their parents, many things about the brother and sister are a tacit offensive and defensive alliance, so Cai Xueying's small temperament is more vividly shown in front of her brother than in front of her parents.

"Uh...... This...... Is it any difference if you take me and I take it? You are my sister, and if you take my brother, of course you will be my brother. Cai Shang had no choice but to show his sister his logical thinking ability.

"Of course it's different!" Of course, Cai Xueying also has her own logic, she pointed to the orange and yellow scarf around her neck and said:

"This is my scarf, can you say that this is also your scarf because I am your sister?!"

"This ......" Cai Shang was speechless by Cai Xueying's logic, and he couldn't find a suitable rebuttal for a while.

Zhou Jianhua listened to Cai Xueying's words, so he had no choice but to laugh on the side, thinking to himself that Cai Xueying's logic was to treat herself as a private exclusive item.

Most of the people who study science and engineering have strong logical thinking skills, and Cai Shang immediately figured out his sister's mentality at this time, and couldn't help but be slyly happy.

PS: Readers, please recommend votes!