U-LI 201 Spectrum Test and Instructions for YBT250-20080613-A-1.0

8/13/2019 U-LI 201 Spectrum Test and Instructions for YBT250-20080613-A-1.0

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HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential

Internal

www.huawei.com

Spectrum Test and

Instructions for YBT250

ISSUE1.0


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HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 1

The WCDMA system is a restricted

communication system by the interference.

The network quality, capacity and coverage

are all related to the background noise.

When design the radio network, we must

obtain the strength of the background noise in

the coverage area.

If strong interference exists within the band,spectrum test need to be performed, or the

operator have to apply for new frequency

spectrum.


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After studying this course, you should be

able to:

Know the sources of electromagneticbackground interference.

Master the methods for electromagnetic

background test.

Know how to use YBT250 for spectrum test.


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Chapter 1 Impact of Electromagnetic

Interference on the System

Chapter 2 Sources of ElectromagneticBackground Interference

Chapter 3 Introduction to Interference

Test Tools

Chapter 4 Methods for Electromagnetic

Background Test

Chapter 5 Instructions for YBT250


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Chapter 1 Impact of Electromagnetic Interference

on the System

1.1 Bands Used in the WCDMA System

1.2 Interference Requirements for UE Reception

1.3 Interference Requirements for NodeB

Reception


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Bands used in the WCDMA system

Operating

Band

UpLink Band

UE transmit, Node Breceive

DownLink Band

UE receive, Node Btransmit

I 1920 - 1980 MHz 2110 -2170 MHz

II 1850 -1910 MHz 1930 -1990 MHz

III 1710-1785 MHz 1805-1880 MHz

IV 1710-1755 MHz 2110-2155 MHz

V 824 - 849MHz 869-894MHz

VI 830-840 MHz 875-885 MHz

VII 2500 - 2570 MHz 2620 - 2690 MHz

VIII 880 - 915 MHz 925 - 960 MHz

IX 1749.9 - 1784.9 MHz 1844.9 - 1879.9 MHz

Band I, II, V and VII are most popular used in the world.

Band I is used in China.


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Impact of Electromagnetic Interference on the System

Determine the impact of interference on the system according to experience, as

shown in the following table (for UE).

Interference Band

Interference Level

Not AffectingReceiver Sensitivity

(With the Sensitivity

Worsened by 0.1 dB)

Acceptable

Interference Level(With the Sensitivity

Worsened by 3 dB)

Acceptable

Interference Level(With the Sensitivity

Worsened by 6 dB)

Interference That SeriouslyEffects Equipment Indexes

Instead of Equipment Running,Lower Than the Maximum Signal

Strength (-25 dBm) the UE Can

Receive by 10 dB

ProtocolRequirement

2110-2170 MHz (co-

frequency interference)-117 dBm/ 3.84 MHz

-101 dBm/ 3.84

MHz-96 dBm/ 3.84 MHz -35 dBm/ 3.84 MHz

The required

sensitivity is -107

dBm/ 3.84 MHz.

2095-2185 MHz (adjacent

channel interference,

deviated from the carrier

by 5 MHz)

-82 dBm/ 3.84 MHz -66 dBm/ 3.84 MHz -61 dBm/ 3.84 MHz -16 dBm/ 3.84 MHz

-66 dBm/ 3.84

MHz (with the

sensitivity

worsened by 3 dB)

2095-2185 MHz (in-band

blocking, deviated from

the carrier by 10 MHz)

-72 dBm/ 3.84 MHz -56 dBm/ 3.84 MHz -51 dBm/ 3.84 MHz -6 dBm/ 3.84 MHz

-56 dBm/ 3.84

MHz (with the

sensitivity

worsened by 3 dB)


blocking, deviated from

the carrier by 15 MHz)

-60 dBm/ 3.84 MHz -44 dBm/ 3.84 MHz -39 dBm/ 3.84 MHz 6 dBm/ 3.84 MHz

-44 dBm/ 3.84

MHz (with the

sensitivity

worsened by 3 dB)

Other bands (out-of-band

blocking and spurious

response)

-60 dBm/ 3.84 MHz -44 dBm/ 3.84 MHz -39 dBm/ 3.84 MHz 6 dBm/ 3.84 MHz

-44 dBm/ 3.84MHz (with the

sensitivity

worsened by 3 dB)

Note:

dBm/Hz refers to the level unit of single-tone signals.

The reference port for measurement is the reception port of the UE antenna.

The reference requirements are based on the protocol TSG25.101.


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Impact of Electromagnetic Interference on the System Determine the impact of interference on the system according to experience,

as shown in the following table (for NodeB).

Interference Band

Interference Level

Not AffectingReceiver Sensitivity

(With the SensitivityWorsened by 0.1 dB)

Acceptable

Interference Level(With the

SensitivityWorsened by 3 dB)

Acceptable

Interference Level(With the

SensitivityWorsened by 6 dB)

Interference That Seriously

Effects Equipment IndexesInstead of Equipment Running,

Lower Than the Maximum

Signal Strength (-70 dBm) the

UE Can Receive by 10 dB

Specification for NodeB

Indexes

1920-1980 MHz (co-

frequency interference)-121 dBm/ 3.84 MHz -105 dBm/ 3.84 MHz -100 dBm/ 3.84 MHz -80 dBm/ 3.8 4MHz

The sensitivity specification

is -123 dBm/3.84MHz.

1900-2000 MHz

(adjacent channel

interference, deviated

from the carrier by 5

MHz)

-63 dBm/ 3.84 MHz -47 dBm/ 3.84 MHz -42 dBm/ 3.84 MHz -22 dBm/ 3.84 MHz-42 dBm/ 3.84 MHz (with the

sensitivity worsened by 6 dB)


blocking)-51 dBm/ 3.84 MHz -35 dBm/ 3.84 MHz -30 dBm/ 3.84 MHz -10 dBm/ 3.84 MHz

-30 dBm/ 3.84 MHz (with the


1900-2000 MHz (out-of-

band blocking)-46 dBm/ 3.84 MHz -30 dBm/ 3.84 MHz -25 dBm/ 3.84 MHz -5 dBm/ 3.84 MHz

-25 dBm/ 3.84 MHz (with the


935-960 MHz

1805-1880 MHz (out-of-

band blocking)

-5 dBm/Hz 11 dBm/Hz 16 dBm/Hz 36 dBm/Hz16 dBm/Hz (with the


Other bands (out-of-

band blocking)-26 dBm/Hz -10 dBm/Hz -5 dBm/Hz 15 dBm/Hz

-5 dBm/Hz (with the


Note:

dBm/Hz refers to the level unit of single-tone signals.

The reference port for measurement is the reception port of the NodeB antenna.

The reference requirements are based on the protocol TSG25.101.

During analysis, the index for adjacent channel interference and in-band blocking is 10 dB better than that specified in the protocol. This is the RF index the NodeBcan ensure.


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Interference requirements for UE reception(taking the band 2110 -

2170 MHz as an example)

Interference band: 2110 - 2170 MHz

Interference level not affecting receiver sensitivity: -117 dBm/3.84 MHz, with

the sensitivity worsened by 0.1 dB

Acceptable interference: -101 dBm/3.84 MHz, with the sensitivity worsened

by 3 dB

Acceptable interference: -96 dBm/3.84 MHz, with the sensitivity worsened by

6 dB

Interference that seriously effects equipment indexes instead of equipment

running:

-35dBm/3.84MHz, lower than the maximum signal strength (-25 dBm) the UE

can receive by 10 dB

Sensitivity: at least -107 dBm/3.84 MHz as required in the protocol


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Interference requirements for NodeB reception (taking the band

1920 -1980 MHz as example)

Interference band: 1920 - 1980 MHz

Interference level not affecting receiver sensitivity: -121 dBm/3.84 MHz, with

the sensitivity worsened by 0.1 dB

Acceptable interference: - 105 dBm/3.84 MHz, with the sensitivity worsened

by 3 dB

Acceptable interference: - 100 dBm/3.84 MHz, with the sensitivity worsened

by 6 dB

Interference that seriously effects equipment indexes instead of equipment

running: -80 dBm/3.84MHz

Sensitivity: at least -123 dBm/3.84 MHz as required in the protocol


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Chapter 2 Sources of Electromagnetic

Background Interference

Chapter 3 Introduction to InterferenceTest Tools


Background Test



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2.1 2G Band Allocation

2.2 Analysis on Interference Sources


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2G Band Allocation

In china, 2G bands are allocated as follows:

Band (MHz) Occupation

1710~1720/1805~1815 GSM1800 for China Mobile

1745~1755/1840~1850 GSM1800 for China Unicom

1800~1805 SCDMA (Beijing Xinwei)

1850~1865/1920~1945 Reserved

1865~1880/1954~1960 PCS1900 (not occupied)

1880~1900/1960~1980 FDD WIL (used by China Telecom and China

Unicom in some cities by the end of 2002)

1900~1920 TDD WLL (PHS/DECT)

Planning of Bands 1.8 GHz and 1.9 GHz in China


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2.1 2G Band Allocation2.2 Analysis on Interference Sources

TDD WLL

FDD WLL

Microwave transmission

Repeater


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Analysis of Interference Sources

TDD WLL (PHS/DECT)

The system occupies the 1900 -1920 MHz band.

For the PHS system, the bandwidth occupied by the channel is

smaller than or equal to 288 KHz.

For the DECT system, the bandwidth occupied by the channel

is smaller than or equal to 1533 KHz.

FDD WLL

Uplink band: 1880 -1900 MHz

Downlink band: 1960 -1980 MHz

The bandwidth occupied by the system is 1.25 MHz.

The EiRP of a typical NodeB is about 25 dBm.


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Analysis of Interference Sources

Microwave transmission

Occupied bandwidth: usually over several MHz.

Normal reception level of microwave is about -60 dBm, imposing a great impact

on the WCDMA system.

Repeater

Nonstandard installation results in insufficient antenna isolation, thus self-

excitation. This affects normal running of the NodeB where the repeater is

installed.

The repeater is a wide-band non-linear amplifier. Its intermodulation index

exceeds the one specified in the protocol. The repeater easily causes

interference to nearby NodeBs when its power is too large.

Others

Some communication devices occupy WCDM bands. Unreasonable installation

and isolation result in high harmonic signals and thus cause interference to the

WCDMA system. In addition, radar is also a common interference source.


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Test Tools


Background Test



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Chapter 3 Introduction to Interference Test Tools

1.1 Spectrum Analyzer

1.2 Antenna

1.3 Low Noise Amplifier


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Interference Test Tools

Spectrum analyzer

A spectrum analyzer is used to test frequency domain features of signals,covering spectrum, adjacent channel power, fast time domain scanning,

spurious radiation and intermodulation attenuation.

Key indexes

Resolution bandwidth (RBW)

Input frequency and central frequency (F0) Sensitivity

Span

Reference level (RefLvl)

Video filter bandwidth (VBW)

Input signal attenuation (ATT) Detection mode (RMS)

Sweep time


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Main technical indexes of various spectrum analyzers

Model Working Band Sensitivity (1 Hz)Minimum Resolution

Bandwidth

HP8591E 30 - 1.8 GHz -145 dBm 30 Hz

HP8594E 30 - 2.9 GHz -142 dBm 30 Hz

HP8595E 30 - 6.5 GHz -142 dBm 30 Hz

HP8561E 30 - 6.5 GHz -145 dBm 1 Hz

YBT250 30 - 2500 MHz -132 dBm 1 KHz


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Antenna

Omnidirectional antenna: It facilitates interference

measurement instead of interference location.

Directional antenna: It is used to search interference sources.

The more distinct the directivity is and the higher the gain is,

the stronger the searching capability is. Common directional antennas:

Panel antenna

Yagi antenna

Log periodic antenna


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Low noise amplifier (LNA)

Used to improve the receiver sensitivity of the testing instrument.

During a test, we can select the LNA with 30 dB gain and 5 dB

noise coefficient.

Additional power supply needs to be considered for the LNA. Some

testing instruments (like YBT250 ) are configured a built-in LNA.

For a cascade network, the noise coefficient of the system depends

on level-1 noise coefficient when a high gain amplifier is configured

at the front end of the system.


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Test Tools


Background Test



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Chapter 4 Methods for Electromagnetic Background Test

4.1 Preparations

4.2 Setting Basic Parameters

4.3 Measurement Procedure

4.4 Data Processing


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Preparations

Master local radio band planning and the usage of radio

equipment by enterprises

For pilot networks

No available frequency is determined and the testing frequency is allocated

temporarily. During a spectrum test, you need to scan the entire band or

select several 5 MHz bands for test according to the local frequency

resources for use at the later phase.

For commercial networks

Frequency resources are determined. The test focuses on the bands used

by the operator and is intended to eliminate interference at the bands in use.


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Preparations

Determine the test time and place

Uplink electromagnetic interference test

Test place: the place where the NodeB antenna is installed.

Conduct the test in three directions (0, 120 and 240).

Use a portable antenna or the NodeBs antenna.

Downlink electromagnetic interference test

Select a certain quantity of typical points within the cell coverage for test.

Conduct the test in three directions (0, 120 and 240).

Use a portable antenna.

Perform a drive test, drive the vehicle slowly along the main streets covered by acell and then stop the vehicle for further test when detecting the interference.


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Preparations

Prepare tools and make surethat they are available:

Spectrum analyzer

GPS receiver

Compass

Testing antenna

Vehicle


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Preparations

Prepare tools and make them available:

Connect an LNA to the spectrum

analyzer with low receiver sensitivity.

During system connection, check

whether connectors are matched and

ensure continuous power supply for

the instruments.

Device Connector Model

Yagi antenna N (female)

Bandpass filter N (female)

YBT250 spectrum

analyzerN (female)

LNA SMA (male)

Feeder N (male)

Feeder N (male)/SMA (male)

50 ohm matched

loadN (male)

YBT250spectrumanalyzer

Yaqi antenna

Filter

LNA

Cable


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4.1 Preparations



4.4 Data Processing


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Setting Basic Parameters

Set the following basic parameters

Parameter Parameter Value Remarks

FoUplink: Fo=1950; downlink: Fo=2140

(MHz)

Central frequency of the

spectrum under test

SPAN For example, SPAN=100 MHzSpan of the testable

spectrum

MaxHold

/Average

Select MaxHoldor Averageaccording

to occurrent or continuous interference

respectively.

Display the maximum

value/the average value

RefLvl

Do notselect AutoLevel. Set the

reference level according to the testing

signal and try to display the signal in themiddle of the spectrum analyzer.

Reference level

Vertical

Scale10 dB/div (default) Vertical scale


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4.1 Preparations



4.4 Data Processing


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Measurement Procedure

Determining the test azimuth Select the position where the NodeB antenna is installed for test. Usually, you

need to conduct the test in three directions. If the direction of the NodeB

antenna is determined, make the testing antenna be in the same direction as

the NodeB antenna.

Searching interference

Search interference within the uplink band and then within the downlink band.

Specific operations:

Enter the YBT250 spectrum test interface and set Fo and Span.

Fill in the record table, save data files, and check whether there is interference.

Judge rule: whether there is interference waveform higher than the noise floor.


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Interference confirmation

During interference search, if there is interference, conduct a interference

confirmation test. Specific steps are as follows:

Enter the interface for measuring YBT250 NodeB test information, and set Foto a

central frequency point near interference,Spanto 3 interference bandwidth,

and Channel Bandwidthto 4 M.

Read the in-band interference power, fill in the record table, and save the data file.

In-band test

For the customer pilot, test the in-band power for all the candidate channels.

For commercial offices, focus on testing the in-band power for the available

channels. Specific steps are as follows:

Enter the interface for measuring YBT250 NodeB test information, and

set Foto a central frequency point of the testing channel, ChannelBandwidthto 5 M, and Spanto 3 interference bandwidth.

Read the in-band power, fill in the record table, and save the data file.


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Downlink drive test

Downlink drive test means driving a vehicle slowly along the main

streets covered by a cell and conducting a point test after discovering

large interference.


Enter the YBT250 spectrum test interface.

Set Foto 2140 MHzand Spanto 60 MHz. Search interference when the

vehicle moves at a speed lower than 15 km/h.

Point test items include:

Set Foto a central frequency point near the interference, Channel

Bandwidthto 4 MHz, and Spanto 3 interference bandwidth. Record the

in-band interference power.

Or set Foto a central frequency point of the testing channel, ChannelBandwidthto 5 MHz, and Spanto 3 channel bandwidth. Record the in-

band power.


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4.1 Preparations



4.4 Data Processing


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Data Processing

After completing measurement, perform data

processing.

After completing measurement for the test area,

output

WCDMA Electromagnetic Interference Test Form

After completing measurement for the entire

local network, output

Report on WCDMA Electromagnetic Interference

Test


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Question

Is the interference level obtained

from the electromagnetic

interference test equal to the

level of the interference signals

at the top of the NodeB or at the

antenna port of the MS?


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Answer

The testing system and WCDMA

system adopt different antennas

and feeders. Therefore, you

need to calculate the level of the

interference signals at the top of

the NodeB or at the antenna port

of the MS according to the test

data during analysis.


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Answer

Testing system Antenna gain: 3 dBi

Feeder loss: 1 dB

Measured interference level: -90 dBm

WCDMA system

Gain of the NodeB antenna: 10 dBi

Feeder loss: 2 dB

Interference level at the NodeB: 90 - (3 -1) + (10 - 2)-84 dBm


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Question

How to estimate the power of the

interference level within the

channel bandwidth according to

the interference level within the

RBW?


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Answer

The WCDMA system is a broadband system.Therefore, you need to calculate theintegral

power of the interference level within the

channel bandwidth.

RBW of the testing system: 10 KHz

Interference level within the RBW: -80 dBm

Channel bandwidth: 3.84 MHz

Integral power within the channel:

P = -80 + 10LOG(3.84*106/10*103) = -54dBm


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Test Tools


Background TestChapter 5 Instructions for YBT250


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System connection

Power-on

Measurement

Measurement setting

Measurement result


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Before site survey, you need to conduct a spectrum testand find proper frequency test instruments.

Tektronix YBT250 is recommended.

Features of YBT250

Portable, easy to carry

System integration, with a built-in LNA


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System connection

The matched antenna of YBT250 is Yagi

directional antenna.

A portable small antenna can be used for

electromagnetic background test.

YBT250 can use the battery deliveredtogether or can be externally connected to

the power supply.

Power-on

Press Powerand enter the Windows CE

operating system.

Enter the measurement interface through

the touch screen of YBT250.

YBT250spectrumanalyzer

Yaqi antenna

Filter

LNA

Cable


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Measurement

YBT250 supports the following three

measurement functions:

NodeB information measurement

Spectrum test

Interference source search

Spectrum test supports the following two

display modes:

Spectrum mode

Spectrogrum mode


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Measurement The spectrum mode is used for real-time measurement.

Determine the band to be tested and set Fo.

Modify the span.

Observe the spectrum diagram, adjust the Fo and span, and view whether there is

interference.

The Tracemenu includes the following options:

Normal, Max Hold, Min Hold and Max/Min Hold

Save the current spectrum diagram.

Note: You need to set RefLvlcorrectly to make the measured signal levelrange from RefLvl to (RefLvl-70dB). The difference of the maximum level and

minimum of level that the YBT250 can correctly display is 70 dB.


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Measurement

The spectrogrum mode is used to check

whether there is interference at a certain band

in a specified time. The horizontal axis stands

for the band and the vertical axis for the time.


Set the automatic storage option and a file name.

Set the band (Fo and span).

Open the saved file and view interference.

To view the exact interference, you can export

the file as:

A picture

Data (.txt,.csv)

Export the data from YBT250 using the U disk or

network cable.


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Measurement setting

Fo: the central frequency of the testing signal (unit: MHz)

Span: It can be set to 100 MHz, 10 MHz or 5 MHz.

RBW: It is automatically set by the instrument according to the span.

MaxHold/Average: display the maximum value and the average value.

RefLvl: set according to the interference level.

Measurement result

WCDMA Electromagnetic Interference Test Formand Report on WCDMA

Electromagnetic Interference Test


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A spectrum trail in the interference windowInstance of displaying signal strength


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Conclusion

This course describes possible

interference sources at the WCDMA

band, methods for electromagnetic

background test, and instructions for

YBT250.


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Thank You!

www.huawei.com

Documents

U-LI 201 Spectrum Test and Instructions for YBT250-20080613-A-1.0