当前位置：网站首页>With st7008, the Bluetooth test is completely grasped

With st7008, the Bluetooth test is completely grasped

2022-07-07 20:10:00 【Professional ate provider】

From smart home 、 Smart city 、 Intelligent industry and other fields , Constantly updating and iterating Bluetooth devices provide people with an infinite possibility of intelligent life . Bluetooth has been integrated into every aspect of our life , Quietly changing our living habits , Make our daily life more convenient . Once simple around us 、 Everything divided , Now start connecting , And become intelligent .

Review Bluetooth V1.0 To V5.2 Technology change , From audio transmission 、 Picture and text transmission 、 video transmission , Then to the Internet of things transmission based on low power consumption . Bluetooth wireless technology is perfect with its encryption measures , The advantages of stable transmission process and abundant compatible devices stand out from many wireless transmission technologies . Especially today when the threshold of authorization is gradually lowered , Bluetooth technology has really spread to all kinds of digital devices .

With the wide application of Bluetooth Technology , bluetooth IC The market demand of is increasing ,ATE Test as Bluetooth IC An important link in the production process , It's also IC The key to quality control , It is a very costly process , How to meet customers' increasingly high test performance requirements while taking into account cost considerations , a ATE New challenges faced by manufacturers .

Today, Xiaobian will bring you to talk about Bluetooth IC ATE Those things tested . Before we start talking about the test plan, let's learn about Bluetooth technology and the iterative development history of Bluetooth technology update .

One 、 Bluetooth Overview

Bluetooth technology is a cutting-edge open wireless communication standard , It can connect desktop computers and laptops wirelessly in a short distance 、 Portable devices 、PDA、 Mobile phone 、 Camera phone 、 The printer 、 Digital camera 、 headset 、 Keyboard or even computer mouse ;

Bluetooth adopts distributed network structure, fast frequency hopping and short packet technology , Support point-to-point and point to multipoint communication , Working in the world 2.4GHz ISM（ I.e. industry 、 science 、 Medical Science ） Frequency band . Its data rate is 1Mbps, Time division duplex transmission scheme is adopted to realize full duplex transmission .

Compared with other wireless technologies ： infrared 、 wireless 2.4G、WiFi Come on , Bluetooth has perfect encryption measures , It has many advantages, such as stable transmission process and abundant compatible devices . Especially today when the threshold of authorization is gradually lowered , Bluetooth technology has really spread to all digital devices . however , Bluetooth is not perfect along the way , from 1.0 To 4.2, To the present 5.0, It's an extraordinary process .

Two 、 History of Bluetooth technology

First generation Bluetooth ： Early exploration of short distance communication

1999 year ： bluetooth 1.0

Early Bluetooth 1.0 A and 1.0B There are several problems with the version , Several manufacturers have pointed out that their products are incompatible with each other . meanwhile , In two devices “ link ”（Handshaking） In the process of , Address of Bluetooth hardware （BD_ADDR） Will be sent out , Anonymity cannot be achieved at the protocol level , Risk of data leakage .

therefore , When 1.0 After the release , Bluetooth was not immediately widely used . Except that there were few kinds of electronic devices corresponding to Bluetooth function at that time , Bluetooth devices are also very expensive .

2001 year ： bluetooth 1.1

bluetooth 1.1 Edition officially included IEEE 802.15.1 standard , This standard defines the physical layer （PHY） Media access control （MAC） standard , For wireless connection between devices , The transmission rate is 0.7Mbps. But because it was an early design , Vulnerable to product interference between the same frequency , Affect communication quality .

2003 year ： bluetooth 1.2

bluetooth 1.2 Version for 1.0 Security issues exposed by version , Improved anonymity , Add the hardware address of shielding equipment （BD_ADDR） function , Protect users from identity sniffing attacks and tracking , At the same time, downward compatibility 1.1 edition . Besides , Four new features have also been added ;

AFH（Adaptive Frequency Hopping） Adaptive frequency hopping technology , It reduces the interference between Bluetooth products and other wireless communication devices ;

Support Stereo Transmission requirements of sound effects , But it can only work as a simplex .

Second generation Bluetooth ： Force transmission rate EDR when

2004 year ： bluetooth 2.0

bluetooth 2.0 yes 1.2 An improved version of , Newly added EDR（Enhanced Data Rate） Technology improves the ability of multitasking and multiple Bluetooth devices running at the same time , The transmission rate of Bluetooth device can reach 3Mbps.

bluetooth 2.0 Duplex mode is supported ： Voice communication can be carried out at the same time , While transferring documents / High quality pictures .

meanwhile ,EDR Technology reduces power consumption by reducing the duty cycle , Due to the increase of bandwidth , bluetooth 2.0 Increased the number of connected devices .

2007 year ： bluetooth 2.1

bluetooth 2.1 Added Sniff Subrating Power saving function , The sending time interval of mutual confirmation signals between devices is changed from that of the old version 0.1 Seconds extended to 0.5 About seconds , Thus, the workload of Bluetooth chip is greatly reduced .

in addition , newly added SSP Easy secure pairing function , Improved pairing experience for Bluetooth devices , At the same time, it improves the use and safety intensity .

Third generation Bluetooth ：High Speed, The transmission rate is as high as 24Mbps

2009 year ： bluetooth 3.0

bluetooth 3.0 Added optional technology High Speed,High Speed Can make Bluetooth call 802.11 WiFi It is used to realize high-speed data transmission , The transmission rate is as high as 24Mbps, It's Bluetooth 2.0 Of 8 times .

bluetooth 3.0 The core is AMP（Generic Alternate MAC/PHY）, It's a new alternative RF Technology , The Bluetooth protocol stack is allowed to dynamically select the right RF for any task .

Power consumption , bluetooth 3.0 Introduced EPC Enhanced power control technology , Supplemented by 802.11, The actual idle power consumption is significantly reduced .

Fourth generation Bluetooth ： main ” Low Energy” low power consumption

2010 year ： bluetooth 4.0

bluetooth 4.0 It is the first Bluetooth integrated protocol specification so far , Integrate the three specifications together . One of the most important changes is BLE（Bluetooth Low Energy） Low power function , Proposed low-power Bluetooth 、 There are three modes of traditional Bluetooth and high-speed Bluetooth ：

” High speed Bluetooth “ Focus on data exchange and transmission ;“ Traditional Bluetooth ” Then communicate with information 、 Focus on equipment connection ;” Low power Bluetooth “ It is mainly connected to devices that do not occupy too much bandwidth , The power consumption is lower than that of the old version 90%.

2013 year ： bluetooth 4.1

bluetooth 4.1 There is little change in transmission speed and transmission range , But there are obvious improvements in software . The purpose of this update is to make Bluetooth Smart Technology eventually became the Internet of things （Internet of Things） The core driving force of development .

Support and LTE Seamless collaboration . When Bluetooth and LTE When the radio signal transmits data at the same time , So Bluetooth 4.1 It can automatically coordinate the transmission information between the two , To ensure simultaneous interpreting , Reduce mutual interference .

2014 year ： bluetooth 4.2

bluetooth 4.2 The transmission speed is faster , Higher than the previous generation 2.5 times , Because Bluetooth is smart （Bluetooth Smart） The capacity of packets is increased , The amount of data it can hold is equivalent to the previous 10 About times .

Improved transmission rate and privacy protection , Bluetooth signals want to connect or track user devices , Must be licensed by the user . Users can safely use wearable devices without worrying about being tracked .

Fifth generation Bluetooth ： Turn on 「 The Internet of things 」 The gate of the times

2016 year ： bluetooth 5.0

bluetooth 5.0 It has faster and longer transmission capability in low power consumption mode , The transmission rate is Bluetooth 4.2 Twice as many （ The speed limit is 2Mbps）, The effective transmission distance is Bluetooth 4.2 Four times the size of （ Theoretically, it can reach 300 rice ）, The packet capacity is Bluetooth 4.2 Eight times . Support indoor positioning and navigation function , combination WiFi It can achieve the precision less than 1 Indoor positioning of meters . in the light of IoT The Internet of things is optimized at the bottom , Strive to serve the smart home with lower power consumption and higher performance .

2020 year 1 month 7 Japan , Held in Las Vegas, USA CES2020 The show , Bluetooth Technology Alliance （Bluetooth Special Interest Group, abbreviation SIG） Announced the upcoming release of a new generation of Bluetooth audio technology standard — Low power audio LE Audio, The new generation Bluetooth audio technology breaks the market monopoly of classic Bluetooth audio , Created a new Bluetooth wireless audio market .LE Audio It not only improves the audio quality , Low power consumption is added , Enable Bluetooth audio to be applied in more scenes .

After introducing the development history of Bluetooth Technology , I believe you have a preliminary understanding of Bluetooth Technology , Next, Xiaobian will BLE（ Low power Bluetooth ） For example , Let's talk about Bluetooth again IC Test requirements and ATE Test plan ;

3、 ... and 、BLE Test requirements

1. Introduction of key technical points in Bluetooth testing

（1） Bluetooth protocol stack

Generic Access Profile（GAP）

front Link Layer Although the process of connection establishment is defined , But it does not reflect Application（ perhaps Profile） level , and GAP Is an interface that communicates directly with applications or configuration files , It implements the following functions ： Definition GAP Layer of Bluetooth device role （role）, Definition GAP Layer is used to realize various communication operation modes （Operational Mode） And process （Procedures）, Definition User Interface About Bluetooth parameters , Including Bluetooth address 、 Bluetooth name 、 Bluetooth PIN Code, etc ;

Host control interface layer （Host Controller Interface, Abbreviation HCI）： Definition Host（ host ） and Controller（ controller ） Communication protocol between , This layer can be software or hardware interface , Such as UART、SPI、USB etc. .

Link Layer Used to control the RF status of the equipment , The device will be in Standby（ standby ）、Advertising（ notice ）、Scanning（ scanning ）、Initiating（ initialization ）、Connection（ Connect ） One of these five states .

because BLE It belongs to wireless communication , Then its communication medium is a frequency band resource in a certain frequency range （Frequency Band）;BLE Our market positioning is individual and civilian , So use free ISM Frequency band （ The frequency range is 2.400-2.4835 GHz）; To support multiple devices at the same time , Divide the whole frequency band into 40 Share , The bandwidth of each is 2MHz, Referred to as RF Channel.

（2） BLE Physical channels

After the above definition ,BLE The physical channel has come out , namely “ The channels are ‘f=2402 +k * 2 MHz, k=0, … ,39’, The bandwidth is 2MHz” Of 40 individual RF Channel.

At link level , take 40 The channels are divided into broadcast channels and data channels , Yes 3 The first channel is advertising channel（ Broadcast channel ）, Namely 37、38、39, For discovering devices （Scanning devices）、 Initialize connection （initiating a connection） And broadcast data （broadcasting date）; The rest 37 Channels are data channel（ Data channel ）, Used for communication between two connected devices .

Broadcast channels are scattered in frequency bands far away , Excessive concentration will lead to serious interference in this frequency band , It may be impossible to broadcast , The purpose of decentralization is to increase fault tolerance .

（3） Bluetooth package format

• There are many common types of Bluetooth packets , But usually only DH (Data High-rate) and DM (Data Medium-rate) Two types will be used in production testing .

• DH、DM There are three levels , They are single time slots 、3 Times timeslot and 5 Multiple time slot , Every DM or DH The data package is marked with corresponding numbers , Used to indicate the length of the packet .

• Standard Data Rate (1Mbps)

* DH1, DH3, DH5

* DM1, DM3, DM5

• EDR 2Mbps Data Rate (pi/4-DQPSK modulation)

* 2-DH1, 2-DH3, 2-DH5

* 2-DM1, 2-DM3, 2-DM5

• EDR 3Mbps Data Rate (8DPSK modulation)

* 3-DH1, 3-DH3, 3-DH5

* 3-DM1, 3-DM3, 3-DM5

（4） Bluetooth payload type （payload）

In production testing, there are three different payload（ Payload ） type , Each of these payload Focusing on the device A test of ：

• PRBS9

* Send a pseudo-random sequence whose spectrum distribution is close to the actual signal , test device Working performance ;

• 10101010

* For modulation filter module ;

* Stress test the output capability of the transmitter by significantly changing the shape of the spectrum ;

• 11110000

* Mainly used to detect DUT Internal Gaussian filter ;

（5） Bluetooth adaptive frequency hopping technology

Bluetooth technology works in 2.4GHz Short distance wireless communication technology on free industrial frequency band , Work at the same time 2.4G There are other wireless communication standards on the frequency , for example 802.11. We know that if two frequencies work in the same frequency band at the same time , Then there will be mutual interference , The quality of data transmission is reduced . So early Bluetooth designers considered these issues , Decide to use FM technology to avoid and 802.11 Frequency competition , That is, it only stays on each fixed frequency for a very short time, and then communicates data on another frequency .

• Adaptive frequency hopping technology （AFH） It is a frequency hopping technology based on automatic channel quality analysis, which combines frequency adaptive and power adaptive control . This technology can make the frequency hopping communication process automatically avoid the interfered frequency hopping points , And with the minimum transmission power 、 The lowest probability of interception , Achieve on the frequency hopping channel without interference , Maintain high-quality communication for a long time ;

• This function is mainly through SCAN To test , And if the PLL If you pass the test, you can ensure that the function can work ;

2. Bluetooth transmitter characteristic test （TX）：

* Output Power

adopt Output Power test , Verify the maximum peak power and average RF output power ;

Initial conditions ：

DUT Direct set at maximum power TX Pattern ;

DUT The initial state of is set to loopback (Loop back);

The link is Frequency hopping, White noise is turned off

The payload emitted by the instrument is PRBS9;

The specification requires peak power <23dBm, Average power <20dbm;

If DUT The power level of is 1, Average power >0dbm;

If DUT The power level of is 2,-6dbm< Average power <4bm;

If DUT The power level of is 3, Average power <0dbm;

* Modulation Characteristics

Modulation characteristic is a method of measuring frequency deviation , Mainly the verification of modulation index ;

Initial conditions ：

The modulation mode is GFSK;

DUT The initial state of is set to loopback (Loop back);

close Frequency hopping;

Two different types of payloads ：

0xF0(11110000)：∆f1

0x55(10101010)：∆f2

test log The index meets the following conditions ：

140kHz ≤ ∆f1avg ≤ 175kHz（ At least 99.9% Of ∆f1avg Satisfy ）

∆f2max ≥ 115kHz（ At least 99.9% Of ∆f2max Satisfy ）

∆f2avg/∆f1avg ≥ 0.8

* 20dB Bandwidth

Test and verify whether the emission within the operating frequency range is within the limit ;

Initial conditions ：

DUT Direct set at maximum power TX Pattern ;

White noise off , Turn off frequency hopping (Frequency hopping);

The chips work at low 、 in 、 Three high frequency points ;

Scan the frequency of Bluetooth tester to find the corresponding frequency point of maximum power ;

Find the corresponding power drop on the left and right sides of the maximum power 20dB At the time of the fL and fH,20dB Of ∆f=|fH-fL|, requirement ∆f<1MHz;

* In-band emissions

The test mainly verifies that the frequency range used by the equipment , come from DPSK The harmful signal level of the transmitter is lower than the required level ;

Initial conditions ：

DUT Set to direct at maximum output power TX Pattern ;

Turn off white noise 、 frequency hopping , Fixed frequency test (fTX=2406MHz、2440MHz、2476MHz);

Set line loss ;

DUT Configure the maximum output power ;

The payload is PRBS9 data format ;

Test evaluation criteria ：

stay fTX=2406MHz、2440MHz、2476MHz when ,PTX≤20dBm( Satisfy Out Power Classes that will do );

stay fTXz±2MHz when ,PTX≤-20dBm;

stay fTXz±[3+n]MHz,n=0,1,2…… when ,PTX≤-30dBm;

3. Bluetooth receiver test （RX）：

* Sensitivity -signal slot packets

Test purpose ： Use non ideal transmitters （ Single slot packet ） Test sensitivity . This test case defines in detail the sending to IUT The signal of .IUT It shall meet the sensitivity required by the non ideal signal .

Initial conditions ：

DUT The initial state of is set to loopback (Loop back);

close Frequency hopping;

DUT Send back to the tester with maximum output power ;

The transmission power of the tester is selected as DUT The input power of the receiver is -70dBm;

* Sensitivity -multi slot packets

Test purpose ： Multi slot data packets are sent at sensitivity level to DUT.（ Maximum length allowed ）. This test case defines in detail the sending to DUT The signal of .DUT It shall meet the sensitivity required by the non ideal signal .