Method and apparatus for random sequence generator

• US 6,414,558 B1
• Filed: 09/18/2000
• Issued: 07/02/2002
• Est. Priority Date: 05/12/1999
• Status: Expired due to Term

• Current Assignee: CEVA Ireland Ltd. (CEVA Incorporated)
• Original Assignee: CEVA Ireland Ltd. (CEVA Incorporated)
• Inventors: Horan, John M., Ryan, John G.
• Primary Examiner(s): MIS, DAVID C
• Application Number:
  US09/664,042
• Time in Patent Office: 652 Days
• Field of Search: 331/78, 327/164, 708/250, 364/717
• US Class Current: 331/78
• CPC Class Codes: H03B 29/00 Generation of noise currents and voltages gasfilled discharge tubes with solid cathode specially adapted as noise generators H01J17/005

Abstract

An apparatus is described comprising a noise source coupled to an input of a gain stage. The apparatus also includes a noise shaping stage that forms a shaped noise signal by reducing 1/f noise introduced by the gain stage. The noise shaping stage has an input coupled to an output of the gain stage. The apparatus also has a decision circuit that decides whether the shaped noise signal, or a signal derived from the shaped noise signal corresponds to a 1 or a 0. A method is described that amplifies a first noise signal to produce a second noise signal. A shaped noise signal is formed by reducing 1/f noise introduced to the second noise signal by the amplifying. A random sequence is generated by comparing, against a reference, the shaped noise signal or a signal derived from the shaped noise signal.

Claims

1. An apparatus, comprising:

a) a noise source coupled to an input of a gain stage;

b) a noise shaping stage that forms a shaped noise signal by reducing 1/f noise introduced by said gain stage, said noise shaping stage having an input coupled to an output of said gain stage; and

c) a decision circuit that decides whether said shaped noise signal corresponds to a 1 or a 0.

2. The apparatus of claim 1 wherein said gain stage is a differential gain stage.

3. The apparatus of claim 1 wherein said noise shaping stage also forms said shaped noise signal by reducing an offset voltage introduced by said gain stage.

4. The apparatus of claim 1 wherein said noise source further comprises a white noise source.

5. The apparatus of claim 4 wherein said white noise source further comprises a resistor.

6. The apparatus of claim 1 wherein said gain stage further comprises an open loop amplifier.

7. A method, comprising:

a) amplifying a first noise signal to produce a second noise signal;

b) forming a shaped noise signal by reducing 1/f noise introduced to said second noise signal by said amplifying; and

c) comparing a said shaped noise signal against a reference to generate a random sequence.

8. The method of claim 7 wherein said 1/f noise is reduced by a correlated double sampling technique.

9. The method of claim 7 wherein said amplifying further comprises differentially amplifying.

10. The method of claim 9 wherein said first noise signal corresponds to the difference between noise generated from a first noise source and noise generated from a second noise source.

11. The method of claim 10 wherein said first noise signal is a white noise signal.

12. The method of claim 7 wherein said amplifying a first noise signal further comprises amplifying a first noise signal without feedback.

13. The method of claim 7 wherein said forming a shaped noise signal further comprises reducing an offset voltage introduced to said second noise signal by said gain stage.

14. An apparatus, comprising:

a) a first means for amplifying a noise signal, said amplifying introducing 1/f noise to said noise signal;

b) a second means for reducing said 1/f noise so as to produce a shaped noise signal; and

c) a third means for deciding whether said shaped noise signal corresponds to a 1 or a 0.

15. The apparatus of claim 14 further comprising a fourth means for providing said noise signal to said first means.

16. The apparatus of claim 14 wherein said first means further comprises a means for amplifying said noise signal without feedback.

17. The apparatus of claim 14 wherein said first means further comprises a means for providing a differentially amplified noise signal.

18. The apparatus of claim 14 wherein said second means further comprises a means for correlated double sampling of said noise signal with said 1/f noise.

19. The apparatus of claim 14 wherein said second means further comprises means for removing an offset voltage introduced to said noise signal by said amplifying.