Pseudo-random bit sequence generator

• US 9,619,206 B2
• Filed: 04/23/2014
• Issued: 04/11/2017
• Est. Priority Date: 05/07/2009
• Status: Active Grant

• Current Assignee: Altera Corporation (Intel Corporation)
• Original Assignee: Altera Corporation (Intel Corporation)
• Inventors: Yan, Junjie
• Primary Examiner(s): Caldwell, Andrew
• Assistant Examiner(s): Brien, Calvin M
• Application Number:
  US14/259,824
• Publication Number:
  US 20140237013A1
• Time in Patent Office: 1,084 Days
• CPC Class Codes: G06F 2207/581 Generating an LFSR sequence, e.g. an m-sequence; sequence may be generated without LFSR, e.g. using Galois Field arithmetic
• CPC Class Codes: G06F 7/582 Pseudo-random number generators
• CPC Class Codes: G06F 7/584 using finite field arithmetic, e.g. using a linear feedback shift register
• CPC Class Codes: H03K 3/84 Generating pulses having a predetermined statistical distribution of a parameter, e.g. random pulse generators

Abstract

The present invention discloses a pseudo-random bit sequence (PRBS) generator which outputs the entire datapath, or entire pseudo-random bit sequence, over one single clock cycle. This is accomplished by removing redundancy, or any redundant exclusive-or gates from linear feedback shift registers; using logic to identify the critical path and optimal shift for the critical path; and dividing the datapath into several pipeline stages to increase the clock rate (i.e., transmission speed).

Claims

1. Bit sequence generation circuitry comprising:

first register circuitry that stores a current state data; and

first combinational logic circuitry that;

receives the current state data from the first register circuitry;

determines a next state data in a single clock cycle by processing the current state data through the first combinational logic circuitry, wherein the next state data is equivalent to an n-bit datapath that would be generated by a linear feedback shift register as a result of n bit-shifts through the linear feedback shift register; and

outputs the next state data;

wherein a critical path of the first combinational logic circuitry comprises a maximum number of logic gates for data to travel through to process from the current state data to the next state data, wherein the maximum number of logic gates is fewer than a number of logic gates that would be applied by the linear feedback shift register over the n bit-shifts through the linear feedback shift register.

2. The bit sequence generation circuitry of claim 1, wherein the first combinational logic circuitry does not include logic gates that would be redundant.

3. The bit sequence generation circuitry of claim 1, wherein the first register circuitry outputs a plurality of pseudo-random bits.

4. The bit sequence generation circuitry of claim 3, wherein the first register circuitry outputs the plurality of pseudo-random bits in the single clock cycle.

5. The bit sequence generation circuitry of claim 1, wherein the logic gates comprise XOR gates.

6. The bit sequence generation circuitry of claim 1, wherein the first register circuitry receives the next state data from the first combinational logic circuitry and replaces the stored current state data with the received next state data.

7. Bit sequence generation circuitry comprising:

first combinational logic circuitry that;

receives a current state data stored in first register circuitry;

determines a next state data in a single clock cycle by processing the current state data through the first combinational logic circuitry, wherein the next state data is equivalent to an n-bit datapath that would be generated by a linear feedback shift register as a result of n bit-shifts through the linear feedback shift register; and

outputs the next state data; and

the first register circuitry that;

receives the next state data from the first combinational logic circuitry; and

replaces the stored current state data with the received next state data;

wherein a critical path of the first combinational logic circuitry comprises a maximum number of logic gates for data to travel through to process from the current state data to the next state data, wherein the maximum number of logic gates is fewer than a number of logic gates that would be applied by the linear feedback shift register over the n bit-shifts through the linear feedback shift register.

8. The bit sequence generation circuitry of claim 7, wherein the first combinational logic circuitry does not include logic gates that would be redundant.

9. The bit sequence generation circuitry of claim 7, wherein logic gates that would be redundant were removed by a hardware platform or a software platform.

10. The bit sequence generation circuitry of claim 7, wherein the first register circuitry outputs a plurality of pseudo-random bits.

11. The bit sequence generation circuitry of claim 10, wherein the first register circuitry outputs the plurality of pseudo-random bits in the single clock cycle.

12. The bit sequence generation circuitry of claim 7, wherein the logic gates comprise XOR gates.

13. The bit sequence generation circuitry of claim 7, wherein the first combinational logic circuitry performs the receiving, determining, and outputting without a clock input.

14. A method for generating a bit sequence comprising:

transmitting current state data stored in first register circuitry to first combinational logic circuitry;

receiving next state data from the first combinational logic circuitry into the first register circuitry, wherein the next state data is determined in a single clock cycle by processing the current state data through the first combinational logic circuitry, wherein the next state data is equivalent to an n-bit datapath that would be generated by a linear feedback shift register as a result of n bit-shifts through the linear feedback shift register, wherein a critical path of the first combinational logic circuitry comprises a maximum number of logic gates for data to travel through to process from the current state data to the next state data, and wherein the maximum number of logic gates is fewer than a number of logic gates that would be applied by the linear feedback shift register over the n-bit shifts through the linear feedback shift register; and

replacing the current state data stored in the first register circuitry with the received next state data.

15. The method of claim 14, wherein the first combinational logic circuitry does not include logic gates that would be redundant.

16. The method of claim 14, comprising outputting, via the first register circuitry, a plurality of pseudo-random bits.

17. The method of claim 16, wherein the plurality of pseudo-random bits are output in a single clock cycle.