Checking of the skew constancy of a bit flow

• US 20050288924A1
• Filed: 06/24/2005
• Published: 12/29/2005
• Est. Priority Date: 06/24/2004
• Status: Active Grant

• Current Assignee: STMicroelectronics SA (STMicroelectronics NV)
• Original Assignee: STMicroelectronics SA (STMicroelectronics NV)
• Inventors: Teglia, Yannick, Liardet, Pierre-Yvan
• Granted Patent: US 7,827,222 B2
• Time in Patent Office: Days
• US Class Current: 704/226
• CPC Class Codes: G06F 7/58 Random or pseudo-random number generators
• CPC Class Codes: G06F 7/588 Random number generators, i.e. based on natural stochastic processes
• CPC Class Codes: H03K 3/84 Generating pulses having a predetermined statistical distribution of a parameter, e.g. random pulse generators

Abstract

A method and a circuit for detecting a possible loss in the equiprobable character of a first output bit flow originating from at least one first element of normalization of an initial bit flow, consisting of analyzing the flow rate of the normalization element.

Claims

1. A circuit for generating a bit flow based on a noise source and on at least one first element for normalizing the initial bit flow provided by this noise source, comprising circuitry for calculating the difference between the input and output flow rates of the normalization circuit.

2. A circuit for generating a bit flow based on a noise source and on at least one first element for normalizing the initial bit flow provided by this noise source, comprising:

at least one second normalization element of the same noise source, of a different flow rate than the first element; and

an element for calculating the difference between the respective flow rates of the two normalization elements.

3. The circuit of claim 2, providing a bit for validating the equiprobable character of the output flow if said difference between the two flow rates remains within a predetermined range of values.

4. A method for detecting a possible loss in the equiprobable character of a first output bit flow originating from at least one first element of normalization of an initial bit flow, said method comprising checking the constancy of the ratio of the rate of the output flow to the initial flow.

6. The method of claim 4, wherein a loss in the equiprobable character of the output bit flow in case of a non-constant flow rate is considered.

5. A method for detecting a possible loss in the equiprobable character of a first output bit flow originating from at least one first element of normalization of an initial bit flow, said method comprising:

submitting the initial flow to at least one second flow rate normalization element different from the first one; and

checking the constancy of the difference between the respective output flow rates.

7. The method of claim 5, comprising checking the constancy of the ratio of the rates of the output flow to the initial flow.