Embedded Systems Design Europe - March 2008 - (Page 34) communications rial bits to be encoded with the clock running at the bit-boundary rate (see Figure 5). When you compare the Manchester-encoded output in Figure 5 with the bit stream in Figure 4, you’ll see the same waveform. DECODING MANCHESTERENCODED DATA Decoding Manchester-encoded data is as easy as encoding it. You simply perform an exclusive-OR of the Manchester-encoded signal with a logical “1” at the bit-boundary sample points, as shown in Figure 6. If you prefer an analog solution for decoding, Figure 7 shows a simple circuit that can achieve the same results. The beauty of this circuit, sometimes called a data-slicer, is that it doesn’t require a synchronizing clock. This eliminates the possibly of errors caused by clock jitters or mismatches between the transmitting and receiving clock signals. The only issue is the values selected for the resistor and capacitor. They must be selected so that the RC-time constant is longer than 1⁄2 the bit-boundary period. This will prevent detection during a setup period. While Figure 7 represents a conceptual view, in practice you would want to create some positive feedback around the amplifier. The positive feedback will provide hysteresis that will help filter out noise that could possibly be misinterpreted as a real Manchester-encoded transition. Once the hysteresis and the RCtime constant have been properly 34 MARCH 2008 | embedded systems design europe | www.embedded.com/europe 031-032-033-034-035-ESDE.indd 34 5/03/08 17:07:56 http://www.embedded.com/europe
Table of Contents Feed for the Digital Edition of Embedded Systems Design Europe - March 2008 Embedded Systems Design Europe - March 2008 Distributors to Increase Embedded Focus Kontron and Quanta to Join Forces Coverity Raises $22m as European Business Booms Help is at Hand for Europe's Industrial Control Developers Milestones in Embedded Systems Microsoft is Recruiting for Embedded Center in Aachen European Designers to Win Cash for Green Designs Duo Work on Smaller Form Factor Europe Invests in Real-Time Java for Multicore Systems Curtiss-Wright Buys Pentland Systems Designing DSP-Based Motor Control Using Fuzzy Logic Lower the Cost of Intelligent Power Control with FPGAs Virtualizing Embedded Linux Back to the Future: Manchester Encoding Is Multicore Hype or Reality New Products Advertising Contacts Embedded Systems Design Europe - March 2008 Embedded Systems Design Europe - March 2008 - Embedded Systems Design Europe - March 2008 (Page 1) Embedded Systems Design Europe - March 2008 - Embedded Systems Design Europe - March 2008 (Page 2) Embedded Systems Design Europe - March 2008 - Embedded Systems Design Europe - March 2008 (Page 3) Embedded Systems Design Europe - March 2008 - Embedded Systems Design Europe - March 2008 (Page 4) Embedded Systems Design Europe - March 2008 - Embedded Systems Design Europe - March 2008 (Page 5) Embedded Systems Design Europe - March 2008 - Kontron and Quanta to Join Forces (Page 6) Embedded Systems Design Europe - March 2008 - Kontron and Quanta to Join Forces (Page 7) Embedded Systems Design Europe - March 2008 - Milestones in Embedded Systems (Page 8) Embedded Systems Design Europe - March 2008 - Milestones in Embedded Systems (Page 9) Embedded Systems Design Europe - March 2008 - Duo Work on Smaller Form Factor (Page 10) Embedded Systems Design Europe - March 2008 - Duo Work on Smaller Form Factor (Page 11) Embedded Systems Design Europe - March 2008 - Curtiss-Wright Buys Pentland Systems (Page 12) Embedded Systems Design Europe - March 2008 - Curtiss-Wright Buys Pentland Systems (Page 13) Embedded Systems Design Europe - March 2008 - Designing DSP-Based Motor Control Using Fuzzy Logic (Page 14) Embedded Systems Design Europe - March 2008 - Designing DSP-Based Motor Control Using Fuzzy Logic (Page 15) Embedded Systems Design Europe - March 2008 - Designing DSP-Based Motor Control Using Fuzzy Logic (Page 16) Embedded Systems Design Europe - March 2008 - Designing DSP-Based Motor Control Using Fuzzy Logic (Page 17) Embedded Systems Design Europe - March 2008 - Designing DSP-Based Motor Control Using Fuzzy Logic (Page 18) Embedded Systems Design Europe - March 2008 - Designing DSP-Based Motor Control Using Fuzzy Logic (Page 19) Embedded Systems Design Europe - March 2008 - Designing DSP-Based Motor Control Using Fuzzy Logic (Page 20) Embedded Systems Design Europe - March 2008 - Designing DSP-Based Motor Control Using Fuzzy Logic (Page 21) Embedded Systems Design Europe - March 2008 - Lower the Cost of Intelligent Power Control with FPGAs (Page 22) Embedded Systems Design Europe - March 2008 - Lower the Cost of Intelligent Power Control with FPGAs (Page 23) Embedded Systems Design Europe - March 2008 - Lower the Cost of Intelligent Power Control with FPGAs (Page 24) Embedded Systems Design Europe - March 2008 - Lower the Cost of Intelligent Power Control with FPGAs (Page 25) Embedded Systems Design Europe - March 2008 - Virtualizing Embedded Linux (Page 26) Embedded Systems Design Europe - March 2008 - Virtualizing Embedded Linux (Page 27) Embedded Systems Design Europe - March 2008 - Virtualizing Embedded Linux (Page 28) Embedded Systems Design Europe - March 2008 - Virtualizing Embedded Linux (Page 29) Embedded Systems Design Europe - March 2008 - Virtualizing Embedded Linux (Page 30) Embedded Systems Design Europe - March 2008 - Back to the Future: Manchester Encoding (Page 31) Embedded Systems Design Europe - March 2008 - Back to the Future: Manchester Encoding (Page 32) Embedded Systems Design Europe - March 2008 - Back to the Future: Manchester Encoding (Page 33) Embedded Systems Design Europe - March 2008 - Back to the Future: Manchester Encoding (Page 34) Embedded Systems Design Europe - March 2008 - Back to the Future: Manchester Encoding (Page 35) Embedded Systems Design Europe - March 2008 - Is Multicore Hype or Reality (Page 36) Embedded Systems Design Europe - March 2008 - Is Multicore Hype or Reality (Page 37) Embedded Systems Design Europe - March 2008 - Is Multicore Hype or Reality (Page 38) Embedded Systems Design Europe - March 2008 - New Products (Page 39) Embedded Systems Design Europe - March 2008 - New Products (Page 40) Embedded Systems Design Europe - March 2008 - New Products (Page 41) Embedded Systems Design Europe - March 2008 - New Products (Page 42) Embedded Systems Design Europe - March 2008 - Advertising Contacts (Page 43) Embedded Systems Design Europe - March 2008 - Advertising Contacts (Page 44)
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