BASE BAND DECODER Project Team Gurrampati Venkatakrishna Reddy Mokrala Srikrishna Chaitanya Under the guidance Bengt Oelmann 2005-03-15

BASE BAND DECODER Introduction Over view of the System Coding Techniques Interfacing of the system Results Conclusion 2005-03-15

BASE BAND DECODER Introduction The Base band decoder project is a part of ZigBee Lite Receiver. Zig bee is new global standard for wireless connectivity focusing on standardizing and enabling interoperability of products with in home control, building automation and industrial control and monitoring. Most wireless sensors use too much power. By resolving this problem we develop the Zigbee. The purpose of this project is to design and implement a hardware module that decodes the bit-stream and convert into bytes to be transmitted. A decoder is a device that decodes a scrambled electronic signal to make it interpretable The function of base band decoder in zig bee is as shown below . 2005-03-15

BASE BAND DECODER BLOCK DIAGRAM 2005-03-15

BASE BAND DECODER WISHBONE INTERFACE: The interface to the microcontroller should be Wishbone. Input parameters S3 & S2 helps in selecting the frequency of the data rate. Input parameters S0 & S1 helps in selecting the type of coding which is to be generated. S3 S2 Freq(Kbps) 10 1 20 40 80 S0 S1 Type of coding NRZ 1 RZ MANCHESTER DIFFERENTIAL 2005-03-15

BASE BAND DECODER FREQUENCY GENERATOR: The function of whole system depends on the Frequency Generator Generation of Data rate Generation of Pclk2 Frequency Generator output is connected to the MULTIPLEXER and SERIAL to PARALLEL converter Data Rate No of Samples/bit 10 4000 20 2000 40 1000 80 500 4000 2000 2005-03-15

BASE BAND DECODER RZ Coding: 0 - Absence of pulse NRZ Coding: 0 - Absence of the pulse 1 - Presence of the pulse NRZ coding in Base band Decoder : Data in = Data out 0 1 0 0 1 1 0 0 0 1 1 0 1 0 0 1 1 0 0 0 1 1 RZ Coding: 0 - Absence of pulse 1 - Presence of pulse in the first half of the bit duration ,the light level returns to zero during the second half RZ coding in Base band Decoder : If start is set to ’1’, the arriving input is the output for twice the max value of count. 1 0 0 1 1 0 0 0 2005-03-15

BASE BAND DECODER Manchester coding: 0 - Upward transition at bit center. 1 - Downward transition at bit center. 1 0 0 1 1 0 Manchester coding in Base band Decoder: The synchronization is obtained by comparing the previous bit with any bit and also counting the duration of half pulse period. when transition is value occurs the count is decreased for the second half of the pulse until it becomes ’0’ when a start bit is sent to indicate the Next pulse starting. 2005-03-15

BASE BAND DECODER Differential manchester coding: 0 - first half of the signal opposite to last half of the previous signal . 1 - first half of the signal equals to the last half of the previous signal. Diff Manchester coding in Base band Decoder: The synchronization is obtained by comparing the previous bit with any bit and also counting the duration of half pulse period. when transition is value occurs the count is decreased for the second half of the pulse until it becomes ’0’ when a start bit is sent to indicate the Next pulse starting. 1 0 1 1 0 0 0 2005-03-15

BASE BAND DECODER Multiplexer: Here, the 40 M-Hz clock and the data rate clock are compared. The transition occurs anywhere in 40 M-Hz clock with respect to the data rate clock’s bit rate and generates the output. The output is sent to serial to parallel converter. Serial to Parallel Converter: It takes 1bit of data at a time as input and generates the output after 8bits of data are stored in it , parallelly. The output is generated in form of serial data in (byte form). 2005-03-15

BASE BAND DECODER RESULTS: Total memory usage is 73300 kilobytes. The outputs of matlab and vhdl are compared and both are same. Total memory usage is 73300 kilobytes. The decoded digital output can be obtained at four different data rates as per the requirement. synthesis report: Number of 4 input LUTs: 585 out of 1536 10% Minimum period: 10.688ns (maximum frequency : 93.563 MHZ) Minimum input arrival time before clock: 11.556ns Maximum output required time after clock: 5.106ns 2005-03-15

BASE BAND DECODER Conclusion: We have successfully obtained the required type of decoding data at the out put as well the signal is continuos. Requirements of the customer have been fulfilled. 2005-03-15

BASE BAND DECODER THANKS: we thank our supervisor Bengt oelmann for his constant vigil and encouragement and all our friends for their support. 2005-03-15