Electronic production internship log

Electronic production internship log

Major: Electronics 0503 Student ID: XX4811 Name: Wang Kang

Internship log Day 1 July 31, 2019

The first internship, I wanted to arrive earlier, but for other reasons, I went to the company at 9:00. I thought I was going to be approved, but the receptionist was more cordial and took me directly to the group. The place. We have a total of 9 people this time, we have to be divided into different groups. One group usually has 1 or 2 people, so it is easier to communicate.

It didn't take long for the person in charge to come. After the brief introduction, we divided the group. My team leader is Zhang Qinghai. Others are very amiable and always have a smile.

Because the first day was just to report, so I didn't go to the base station, they are going to take me to see it the next day.

When I arrived at the group, Master Zhang gave us some basic knowledge of base stations. The base station is a site in the communication transmission. As for how to wait, I will wait until tomorrow. If the signal can be transmitted, it will set a lot of sites, but the site may have some faults, which will affect the signal transmission. We are dealing with the fault. Therefore, the stations are monitored by the monitoring center for 24 hours. When the monitoring center finds a problem, we must immediately go to the station to find out what is wrong, and then notify the corresponding department to go to the repair.

Internship log 2nd day August 1, 2019

Nothing happened today, the team leader took us to the inspection. Every group in every month has to inspect all of its own sites, and it has to go regardless of whether there are any problems. The inspection is to count the model, quantity, and specifications of the equipment in the base station. Put the completed form in the base station for later inspection. Today is the first day of August, and naturally start cleaning up all the sites.

Into the base station, the temperature inside is 23 or 24. It’s especially cool in the summer, and there are a lot of equipment inside. Generally divided into the following systems: transmission systems, including sdh equipment, optical cables, cables, etc.; power systems, batteries, utility power, etc.; moving loop monitoring systems; antenna feeder systems; bts main equipment; and other auxiliary equipment, such as air conditioning , security doors and more. The temperature inside is kept at 23 ° C or 24 ° C. Because it is particularly cool in the summer, but some air conditioners are broken, the temperature inside can reach above 40 °C. Because it is a patrol, it is especially simple.

The so-called patrol is to make a statistics of the names, types, numbers and models of all the devices in the base station. It may be convenient for later inspection. We have four people in this group, two drivers, but we also have jurisdiction over about 50 sites. The base station in my understanding should be a midpoint of signal transmission, just like the bus platform, with it you can easily go to various places, and the base station signal can be transmitted farther and wider.

Because of the first day of inspection, there was no problem with the problem. We just went into the statistics of the model and number of the equipment inside, and then placed it in the base station to complete today's work. Tomorrow is to deal with the fault.

Internship log The third day, August 2, 2019

Today, there is a lot of gains in general, because it is finally a problem. . . . Oh, something is done.

In the morning, the monitoring center called and said that the base station in Tumu Village had been seriously rushed. So our group immediately set off for Tumu Village. When I found out that the AC transformer outside the house was open, the colleague who took me said to myself, "I clearly remembered that when I left, I shut him down. Is anyone stealing electricity?" In fact, I still don't know what he asked this question. He went up to get this done, I was thinking that we would not do this. Later I learned that I was completely wrong.

Later, we went in and looked at the following. He checked several devices and found that there was no problem. The air conditioner inside was also running normally. This is strange. Later, the driver's master came in. He said to us: "I asked the people here, and there has been a power outage since last night." Colleagues did not say anything. Then we will work.

In the car, I asked him what was wrong with it. He said that it is a blackout problem, and we have no generators today. It is not very important here, so please check it again when there is electricity. If you bring a generator, you may have to guard the power here, and you have to pull the cable. It seems that doing base station maintenance is also very hard.

Internship log 4th day August 3, 2019

Today is the day when the Olympic torch arrived in Chengdu. Haha, ease, because we are going to the Panda Park to look after the base station there, to ensure that the torch relay process will not cause communication problems.

Because we need to go to work, so we don’t have to give tickets to the Panda Park. Hey, after I went in, I went to the Panda Park with Longjun’s “Guide” under Master Zhang’s “Guide” and said that we didn’t come once. easily.

By 6 o'clock in the afternoon, the torch was over, and we successfully completed the task~~ Two hard masters pulled ~

In fact, this mission is very important. The Olympic Games are highly valued throughout the country, and we have to pay more attention to communication. Because the communication is interrupted, the consequences can be very serious. So before the torch came, the superior had already arranged it. The site is also divided into several categories, and some important sites have to enter the market, that is, move there to live, to ensure that the communication is unimpeded. So when I arrived at the company, some people actually lived in the heavyweight site. And our internship is not so heavy, it will be easy to pass ~~

Internship log 7th day August 6th, 2019

The base station system that arrives today is rbs883. After the installation and commissioning, the base station can work normally. After running for a period of time, the exchange side test found that the tenth carrier frequency of the b cell in the system has no transmit power. After observing the scene, it is found that the corresponding comb can not be tuned.

First replace comb, the problem remains, prove that comb is normal; connect the power meter to the tx port of trm, use the lctrl1 software to turn the power of trm, and find that the power meter has power display, which proves that the channel disc is normal; generally speaking, if power monitoring If the unit or directional coupler is bad, it will cause problems in all the carrier frequencies of the cell, and not a certain carrier frequency. Therefore, we can conclude that the power monitoring unit and the directional coupler have no problem.

So we turned our attention to the connection: after connecting the pi output head of the comb end with the adjacent carrier frequency and connecting the motor, it was found that the carrier frequency can work normally, but the adjacent carrier frequency can not work, thus positioning the obstacle. On the pi output line and the motor connection line; after replacing the connection from the pi port on the power combiner to the comb port on the power monitoring unit, the carrier frequency works normally and the problem is solved.

These problems are caused by the connection between the pi port on the power synthesizer and the comb port on the power monitoring unit. The power monitoring unit cannot receive the -32db RF signal coupled from the power synthesizer, and thus cannot control the comb tuning.

Internship log 8th day August 7th, 2019

Today's base stations use the rbs200 system. A certain carrier frequency can't work: the test side test reaction is that the carrier frequency receiving is normal but cannot be effectively transmitted; when the base station observes, the carrier frequency is in the process of pushing, rrx, trxc and spu are all normal, and rtx is not effective. Locked, causing the entire carrier frequency to not work properly.

The rbs200 is generally in the form of an auto-tuning synthesizer. The auto-tuner is essentially a narrow-band combiner whose input is mechanically tuned to the specified gsm frequency. At the input of each combiner there is a stepper motor that is controlled by the rtx to which it is connected. The two inputs are combined into one output, and the outputs of several synthesizers can be wired into a single chain. During tuning, the transmitter sets the input of its combiner to a position that gives the maximum forward power, and also checks the reflected back power. If the reflected power exceeds the maximum allowable value, the transmitter disables itself and sends out An error code.

We checked and replaced the hardware devices comb, rtx and txd. As a result, when checking rtx, we found that the needle in the "pt" connection of the rtx collapsed, causing the rtx to be ineffective contact with the RF line from txd. Rtx can't receive the reference signal added from txd feedback, can't analyze and compare the signal with its own transmit signal, and can't control the auto-tuning synthesizer to accurately tune to the corresponding frequency point, so the carrier frequency can't work normally. . After the needle in the "pt" connection of the rtx is dialed, the carrier frequency works normally.

Internship log 10th day August 9, 2019

There is nothing to do today, let’s talk about the hardware causing the base station alarm. After one of the base stations is installed and commissioned by the engineering bureau, the base station can work normally. However, after a period of traffic statistics analysis, it is found that the a and b cells of the base station have higher congestion and dropped calls. Observed by bsc, it is found that the a and b cells of the station have diversity receiving alarms, and the a cell also has an alarm of standing wave ratio. Observed by the omt to the base station, it is found that there is a diversity reception loss alarm and a vswr/power detection loss alarm.

Since the alarms are all related to the antenna feeder system, we first tested the four antenna feeders of the a and b cells with the standing wave ratio tester. The results show that the measured values ​​are within the standard range, which proves that the antenna feeder itself has no problem. We know that diversity acceptance is one of the important measures to solve signal fading and improve signal reception intensity. The cell receives signals through two receiving antennas, and can generate a gain of about 3 db. At the same time, it is judged whether the receiving system is normal by comparing the two signals. If the strength of the two signals detected by tru is very different, the base station will generate a diversity reception loss alarm. The diversity reception loss alarm may be caused by tru, cdu, radio connection to tru or antenna feeder failure.

In this fault detection, we notice that both the a and b cells have diversity receiving alarms and the congestion and dropped calls are high, so the antenna feeders of the a and b cells are suspected to be misaligned. After the high-altitude workers checked the antenna feeders one by one, it was found that the receiving antennas of the a and b cells were misaligned with each other. Therefore, the receiving antennas of the two receiving antennas of the a and b cells are inconsistent, and the antennas in the wrong direction do not receive the signal sent by the mobile phone of the cell or the receiving signal is weak, so that the cell generates a diversity receiving loss alarm and is accompanied by high congestion and Dropped words. After the change, the diversity reception loss alarm disappears, and the congestion and dropped calls fall within the scope of the indicator.

Internship log 11th day August 10, 2019

One of the base stations of the base station that went to check today failed and exited the service. The channel "malf" is displayed on the monitoring terminal, and the self-diagnosis information of the system is called from the management terminal to display the status of the channel: ?diag? 8?11?54. . ?. . ?03 ma 00 tib 22 075 c 00 21

?Time Date System activation master device device name device number status report target information)

Firstly, the frequency and power of the channel are measured, and the frequency is found to meet the requirements of the index. The power is only about 10w. After the overhaul, it is known that the fourth power tube of the final stage power amplifier is damaged, and the power is up to standard after replacement. However, after accessing the system, the channel machine still cannot enter the service state, and the diagnostic information remains. Again measure its frequency and power, both values ​​meet the requirements of the indicator. The analysis may be that the working frequency of the channel is interfered. After the frequency sweep, there is indeed an interference source. After the interference source is removed, the channel machine returns to the normal service state.

Interference is an important factor that limits the performance and capacity of wireless communication systems. It can cause crosstalk, loss of call or dropped call signals and unsatisfactory call quality. The most important thing is that interference limits operators' reusability. The closeness of the frequency. Interference may come from another mobile terminal, other wireless communication devices operating at the same frequency, or out-of-band RF energy that is dissipated into the allocated spectrum. The most common types of cluster interference are co-channel interference and adjacent channel interference. After the occurrence of interference, the source of the interference and the cause of the interference should be ascertained as soon as possible, and the loss due to the interference should be minimized as much as possible.

Although the Motorola Smartnet ii system is a cluster communication system with high intelligence and reliability, it will also have various faults in actual operation, in order to ensure smooth communication, especially to ensure the smooth communication of important departments. We need to fully grasp the system performance, continuously summarize the lessons learned in the daily maintenance process, and strive to improve the system maintenance level.

Internship log 12th day August 11, 2019

Today is the last day of the internship. I was looking forward to doing something more~~ As a result, our base station security system is doing quite well. This is also a good thing, huh, huh. Master Zhang and the driver took us out to inspect the two base stations, came back after visiting, and wrote several reports. We talked a lot about the company apartments we were resting in. There were a lot of questions about the maintenance of the base station about the Olympics. For more than 10 days, we have got along very well with Master Zhang. Now it’s really reluctant to leave, especially the air-conditioned rescue vehicle. However, there is no banquet in the world. When I left, I only thanked them for their careful teaching and patient explanation, especially the amiable master Zhang Qinghai.

At 2 o'clock in the afternoon, we left the apartment, I was very sad, I hope they can work smoothly.