Reduced peak EMI bus using variable bit rate spreading
View Patent ↗Systems and methods are described for a reduced peak EMI bus using variable bit rate spreading. A method for reducing radiated Electro-Magnetic Interference from a wire communication bus transferring data between one or more physically separate modules or units comprises changing a data clock period controlling a rate of data bits on a communications bus. A Distributed Systems Interface communication bus data transmission protocol includes: alternating a data bit-rate between a first bit-rate and a second bit-rate on a bit-by-bit basis; transmitting a bit over the distributed systems interface communication bus according to the alternating data bit-rate; and varying a difference between the first bit-rate and the second bit-rate.
1. A method for reducing radiated Electro-Magnetic Interference from a wire communication bus, comprising:
alternating a data clock period between a first period and a second period on a bit-by-bit basis;
transmitting a bit over the communication bus according to a bit-rate defined by the data clock period; and
varying a difference between the first period and the second period.
2. The method of claim 1 , further comprising alternating the data clock period between the first period and the second period on a message-by-message basis.
3. The method of claim 1 , further comprising alternating the data clock period between the first period and the second period on a word-by-word basis.
4. The method of claim 1 , further comprising transmitting a command over the wire communication bus.
5. The method of claim 1 , wherein varying the difference includes varying the difference proportionally to a number of an iteration.
6. The method of claim 1 , wherein varying a difference includes continuously varying the difference.
7. The method of claim 1 , wherein varying the difference includes varying the difference according to a look-up table.
8. The method of claim 1 , wherein varying the difference includes varying the difference according to a pseudo-random sequence.
9. The method of claim 1 , further comprising spreading an energy across a frequency range.
10. The method of claim 1 , further comprising reducing a peak Electro-Magnetic Interference.
11. The method of claim 1 , wherein alternating the data clock period includes alternating a clock signal embedded into a data stream.
12. The method of claim 1 , further comprising resetting the difference to an initial value when the bit-rate reaches a limit.
13. A computer readable media comprising computer executable instructions, where the instructions, when executed, reduce radiated Electro-Magnetic Interference from a wire communication bus by:
alternating a data clock period between a first period and a second period on a bit-by-bit basis;
transmitting a bit over the communication bus according to a bit-rate defined by the data clock period; and
varying a difference between the first period and the second period.
14. A Distributed Systems Interface, for being coupled to a wire communication bus, the distributed systems interface reducing radiated Electro-Magnetic Interface from the wire communication bus and comprising:
a processor for providing data and a data clock; and
a communications generator coupled to the processor, the communications generator alternating a data clock period between a first period and a second period on a bit-by-bit basis, transmitting a bit over the wire communication bus according to a bit-rate defined by the data clock period, and varying a difference between the first period and the second period.
15. A Distributed Systems Interface communication bus data transmission protocol, comprising:
alternating a data bit-rate between a first bit-rate and a second bit-rate on a bit-by-bit basis;
transmitting a bit over the distributed systems interface communication bus according to the alternating data bit-rate; and
varying a difference between the first bit-rate and the second bit-rate.
16. The Distributed Systems Interface data transmission protocol of claim 15 , further comprising alternating the data bit-rate between the first bit-rate and the second bit-rate on a command-by-command basis.
17. The Distributed Systems Interface data transmission protocol of claim 15 , further comprising transmitting a command over the communication bus.
18. The Distributed Systems Interface data transmission protocol of claim 15 , wherein varying the difference includes varying the difference proportionally to a number of an iteration.
19. The Distributed Systems Interface data transmission protocol of claim 15 , wherein varying a difference includes continuously varying the difference.
20. The Distributed Systems Interface data transmission protocol of claim 15 , wherein varying the difference includes varying the difference according to a look-up table.
21. The Distributed Systems Interface data transmission protocol of claim 15 , further comprising resetting the difference to an initial value when the data bit-rate reaches a limit.
22. The Distributed Systems Interface data transmission protocol of claim 15 , wherein varying the difference includes varying the difference according to a pseudo random sequence generator.
23. A computer readable media comprising computer executable instructions for implementing the Distributed Systems Interface communication bus data transmission protocol, the instructions implementing the protocol when executed, said protocol comprising:
alternating a data bit-rate between a first bit-rate and a second bit-rate on a bit-by-bit basis;
transmitting a bit over the distributed systems interface communication bus according to the alternating bit-rate; and
varying a difference between the first bit-rate and the second bit-rate.