Digital security system

• US 20070142943A1
• Filed: 12/19/2005
• Published: 06/21/2007
• Est. Priority Date: 12/19/2005
• Status: Active Grant

• Current Assignee: NXP USA, Inc. (NXP Semiconductors NV)
• Original Assignee: SigmaTel Incorporated (NXP Semiconductors NV)
• Inventors: Torrini, Antonio, Shkolnyy, Konstantin
• Granted Patent: US 7,949,131 B2
• Time in Patent Office: Days
• US Class Current: 700/94
• CPC Class Codes: G11B 20/00086 Circuits for prevention of unauthorised reproduction or copying, e.g. piracy indicating unauthorised use of record carriers in general G11B23/28; scrambling for television signal recording H04N5/913; network architectures or network protocols for network security H04L63/00; cryptographic mechanisms or cryptographic arrangements for secret or secure communication H04L9/00
• CPC Class Codes: G11B 20/00731 involving a digital rights management system for enforcing a usage restriction
• CPC Class Codes: G11B 20/00818 wherein the usage restriction limits the signal quality, e.g. by low-pass filtering of audio signals or by reducing the resolution of video signals
• CPC Class Codes: G11B 20/10037 A/D conversion, D/A conversion, sampling, slicing and digital quantisation or adjusting parameters thereof
• CPC Class Codes: G11B 20/10527 Audio or video recording; Data buffering arrangements G11B20/12 - G11B20/18 take precedence
• CPC Class Codes: G11B 2020/00057 MPEG-1 or MPEG-2 audio layer III [MP3]
• CPC Class Codes: G11B 2020/10546 specifically adapted for audio data

Abstract

A system and method for processing a digital audio signal is disclosed. The system includes an input to receive a digital audio signal and a first output to provide a first digital output signal. The digital audio signal has a first fidelity characteristic and the first digital output signal has a second fidelity characteristic. The second fidelity characteristic is determined in response to security information extracted from the digital audio signal. The first digital output signal is provided to a digital to converter.

Claims

1. A system, comprising:

an input to receive a digital audio signal, the digital audio signal having a first fidelity characteristic;

a first output to provide a first digital output signal having a second fidelity characteristic, wherein the second fidelity characteristic is determined in response to security information extracted from the digital audio signal; and

wherein the first digital output signal is provided to a digital to analog converter.

2. The system of claim 1, wherein the digital audio signal includes a third fidelity characteristic, and wherein the first digital output signal includes a fourth fidelity characteristic, and wherein the fourth fidelity characteristic is determined in response to the security information.

3. The system of claim 1, further comprising:

a security module to extract the security information from the digital audio signal.

4. The system of claim 3, further comprising:

a first signal processing module to set the second fidelity characteristic.

5. The system of claim 1, wherein the first fidelity characteristic is a first sample rate and the second fidelity characteristic is a second sample rate.

6. The system of claim 1, wherein the first fidelity characteristic is a first bit depth rate and the second fidelity characteristic is a second sample rate.

7. The system of claim 6, wherein the second sample rate is less than or equal to about 48 kilohertz.

8. The system of claim 1, wherein the first fidelity characteristic is a first bit depth and the second fidelity characteristic of a second bit depth.

9. The system of claim 1, wherein the first fidelity characteristic is a first signal to noise ratio and the second fidelity characteristic is a second signal to noise ratio.

10. The system of claim 1, wherein the first fidelity characteristic is a first distortion level and the second fidelity characteristic is a second distortion level.

11. The system of claim 1, further comprising:

a second output to provide a second digital output signal having a third fidelity characteristic.

12. The system of claim 1, wherein the security information includes digital rights management information.

13. A system comprising:

a digital to analog converter to receive a first digital signal, wherein a fidelity characteristic of the first digital signal is based on security information associated with a digital audio source of the first digital signal; and

wherein the digital to analog converter converts the first digital analog signal to an analog output.

14. The system of claim 13, further comprising:

processing logic to receive a second digital signal, wherein a fidelity characteristic of the second digital signal is based on security information associated with the digital audio source.

15. The system of claim 13, wherein the fidelity characteristic of the first digital signal is one of a sample rate, a bit depth, a signal to noise ratio, or a distortion level.

16. A method, comprising:

receiving a digital audio input signal;

extracting first security information at a first time from the digital audio input signal;

setting a fidelity characteristic of a digital output signal to a first level based on the extracted first security information; and

providing the digital output signal to a digital to analog converter.

17. The method of claim 16, further comprising:

extracting second security information at a second time from the digital audio input signal;

setting a fidelity characteristic of the digital output signal to a second level based on the extracted second security information.

18. The method of claim 16, wherein the fidelity characteristic is a sample rate.

19. The method of claim 18, wherein the sample rate is about 48 kilohertz.

20. The method of claim 16, wherein the first security information is associated with a digital rights management protocol.

21. The method of claim 16, wherein an analog output based on the digital output signal has a signal to noise ratio of less than about 96 dB.

22. A method, comprising:

receiving a digital audio signal, wherein a fidelity characteristic of the digital audio signal is modified based on security information associated therewith; and

converting the digital audio signal to an analog output signal.

23. The method of claim 22, wherein the fidelity characteristic of the digital audio signal is one of a sample rate, a bit depth, a signal to noise ratio, or a distortion level.

24. The method of claim 22, further comprising:

providing the analog output signal to a speaker.

25. The method of claim 22, wherein the security information is associated with a digital rights management protocol.

26. A computer readable medium having a computer program embedded within the computer readable medium, the computer program comprising:

instructions to extract first security information at a first time from a digital audio input signal;

instructions to set a fidelity characteristic of a digital output signal to a first level based on the extracted first security information; and

instructions to provide the digital output signal at an output.

27. The computer readable medium of claim 26, further comprising:

instructions to extract second security information at a second time from the digital audio input signal; and

instructions to set a fidelity characteristic of the digital output signal to a second rate based on the extracted second security information.