ISM Band Device Test

Transcription

1 ISM Band Device Test

2 Agenda ISM Band Background Modulation and Parametric Testing of ISM Band ISM Device Test Demonstration ZigBee ZigBee Demonstration

3 Industrial, Scientific and Medical Radio Band Originally reserved internationally for non-commercial use of RF electromagnetic fields for industrial, scientific and medical purposes Available bands but not all countries: MHz MHz MHz MHz MHz GHz GHz GHz GHz GHz GHz Yellow Indicates important frequencies for RFID, WiFi, ZigBee, and Bluetooth

4 Custom ISM Band Applications Biomedical RFID Automotive Keyless entry RF-Keys Controls for Multimedia etc Consumer electronics Remote Controls Cordless Headphones & Microphones Home Automation Toys Wireless Personal Area Networks (WPAN) Bluetooth ZigBee

5 Modulation schemes FM Used in cordless headphones and microphones ASK Very easy to implement Information is mostly not encoded in the Amplitude but pulse-pause encoded (Miller, FM0, PCM, ) Used in remote controls, RFID, Tire Pressure Monitoring FSK / PSK More complicated to implement and to decode Also very often used with some kind of data encoding Used in more advanced applications like Audio & Video streaming applications

6 Data Encoding Transmitted data is very often encoded A series of 1s makes detection of single bits complicated Encoding adds additional transitions to transmitted signal Makes decoding easier Easier to sync on To prevent DC components in transmitted signal Common encoding schemes Manchester Miller FM0 PWM

7 Data Formatting Digital waveform to generate: Data NRZ RC FM0 Manchester PWM not easy for the receiver to sync on high DC component always transition on start of bit transition in middle of bit = 0 no transition in middle of bit = 1 inversion also possible transition LOW to HIGH = 0 transition HIGH to LOW = 1 inversion also possible used in IEEE ms HIGH, 1.8 ms LOW = ms HIGH, 0.7 ms LOW = 1 Symbols 1 and 0 do not have equal length

8 Manchester Encoding Very easy to implement From the input data take a bit and replace it with two bits Replace TRUE with FALSE and TRUE Replace FALSE with TRUE and FALSE Manchester Encoding doubles the number of bits Manchester Encoding doubles the baud rate

9 Manchester Decoding 1. Look for the first 01 or 10 combination in the Manchester encoded data to sync on 2. From the input data take two bits at a time if they represent the values 10 the resulting data bit is 0 if they represent the values 01 the resulting data bit is 1 3. Check for errors: 11 and 00 are illegal input combinations! (hidden in default case)

10 Traditional versus Modular Instrumentation Standalone Instrumentation Modular Instrumentation LAN-, USB GPIB-based PXI, VXI Proprietary Processor, OS Firmware Timing and Control Bus Measurement Subsystem Power Supply Fixed User Interface Timing and Control PC Processor, OS Software Bus Modular Hardware Shared Power Supply User Interface GPIB, LAN, USB Connectivity GPIB, LAN, USB Connectivity

11 Advantages of Modular Instrumentation Custom encoding is different with many ISM Standards One platform to cover multiple ISM standards PXI Platform is well suited for manufacturing test Size, cost, speed, operating temperature, flexibility

12 Measurements & Modulation for ISM Band Test Modulation Toolkit for LabVIEW and LabWindows/CVI Analog and Digital modulation formats AM, FM, PM ASK, FSK, MSK, GMSK, PAM, PSK, QAM Visualization 2D and 3D Eye, Trellis, Constellation Modulation Analysis BER, MER, EVM, burst timing, frequency deviation, ρ (rho) Impairments Additive White Gaussian Noise (AWGN) DC offset, Quadrature skew, IQ gain imbalance, phase noise Equalization, Channel Coding, Channel Models

13 Spectral Measurements Toolkit Parametric Measurements Power in Band Occupied Bandwidth Adjacent Channel Power Frequency Amplitude Zero span or IQ time domain IQ Power Trigger Phase Noise

14 ISM Band Device Test Demonstration FSK Transmitter DUT Digital I/O controller interface Parametric measurements Power in Band Occupied Bandwidth Adjacent Channel Power Frequency Amplitude Modulation measurements BER EVM

15 ISM Band Device Example: IEEE and ZigBee

16 Technology Overview Wireless Personal Area Networks (WPAN) Short range wireless networks Exchange information within personal space of m The latest technologies which represent WPANs are Bluetooth and ZigBee The diagram highlights the wireless personal area network sphere which includes industrial control and monitoring, home automation, sensor networks, medical solutions

17 ZigBee - IEEE std IEEE Std specifies two PHYs and a MAC sub layer PHY s /915 MHz Direct Sequence Spread Spectrum (DSSS) PHY MHz DSSS PHY The 2450 MHz PHY supports an over-the-air data rate of 250 kb/s, and the 868/915 MHz PHY supports over-the-air data rates of 20 kb/s and 40 kb/s. The PHY chosen depends on local regulations and user preference. i MHz (e.g., Europe), ii MHz (e.g., North America) or iii MHz (worldwide).

18 Operating Frequency Range Channel assignments Totally 27 channels, numbered 0 to 26, across the 3 frequency bands. 16 channels in 2450 MHz band 10 in 915 MHz band 1 in 868 MHz band

19 Applications The typical applications of IEEE /ZigBee Wireless Sensor Networks Industrial Monitoring and Control Home Automation Interactive toys Smart badges Remote controls IEEE /ZigBee and SeaSolve ZigBee and the underlying IEEE promise to give the market a cost-effective standards-based wireless network that supports low data rates, low power consumption, security, and reliability.

20 ZigBee Solutions from SeaSolve WiPAN LVSA /ZigBee PHY Signal Analysis Solution WiPAN LVSG /ZigBee PHY and MAC Signal Generation Solution WiPAN LVCT /ZigBee compliance testing Solution Overall test bed and testing strategy to evaluate products for performance, interoperability and compliance.

21 Demonstration: IEEE Automated Test