INFRARED SIGNAL DECODE CIRCUIT AND INFRARED SIGNAL DECODE METHOD

• US 20100266075A1
• Filed: 11/18/2009
• Published: 10/21/2010
• Est. Priority Date: 04/16/2009
• Status: Active Grant

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: YAMAMOTO, Toshifumi, CHIBA, Norikatsu, IWATA, Shigeyasu
• Granted Patent: US 7,877,024 B2
• Time in Patent Office: Days
• US Class Current: 375/343
• CPC Class Codes: G08C 23/04 using light waves, e.g. infrared

Abstract

According to one embodiment, an infrared signal decode circuit includes: a comparator; a correlation signal generator generating a sum of a first detection signal and a second detection signal as a correlation signal, the first detection signal being obtained by performing an absolute value calculation on a first correlation signal, the second detection signal being obtained by performing an absolute value calculation on a second correlation signal, the first correlation signal corresponding to a correlation between a binary signal and a first reference signal with a frequency substantially identical to a base frequency of a subcarrier of an infrared signal, the second correlation signal corresponding to a correlation between the binary signal and a second reference signal with a phase that differ from a phase of the first reference signal by 90 degrees; and a decoder binarizing the correlation signal generated by the correlation signal generator.

Claims

1. An infrared signal decode circuit, comprising:

a comparator configured to compare an electric signal converted from an infrared signal with a sampling frequency greater than or equal to double of a subcarrier frequency contained in the infrared signal to convert the electric signal to a binary signal;

a correlation signal generator configured to generate a sum of a first detection signal and a second detection signal as a correlation signal, the first detection signal being obtained by performing an absolute value calculation on a first correlation signal, the second detection signal being obtained by performing an absolute value calculation on a second correlation signal, the first correlation signal being a first correlation value within a sampling interval, the second correlation signal being a second correlation value within a sampling interval, the first correlation value corresponding to a correlation between the binary signal and a first reference signal with a frequency substantially identical to a base frequency of a subcarrier of the infrared signal, the second correlation signal corresponding to a correlation between the binary signal and a second reference signal with a phase that differ from a phase of the first reference signal by 90 degrees; and

a decoder configured to binarize the correlation signal generated by the correlation signal generator and output the binarized correlation signal as a decode signal.

2. The infrared signal decode circuit of claim 1, wherein the correlation signal generator and the decoder are configured by a digital circuit.

3. The infrared signal decode circuit of claim 1, wherein the comparator is configured by a one-bit comparator.

4. The infrared signal decode circuit of claim 1, further comprising an amplifier configured to amplify the electric signal, wherein the amplifier has a variable gain.

5. An infrared signal decode method, comprising:

comparing an electric signal converted from an infrared signal with a sampling frequency greater than or equal to double of a sub carrier frequency contained in the infrared signal to convert the electric signal to a binary signal;

generating a sum of a first detection signal and a second detection signal as a correlation signal, the first detection signal being obtained by performing an absolute value calculation on a first correlation signal, the second detection signal being obtained by performing an absolute value calculation on a second correlation signal, the first correlation signal being a first correlation value within a sampling interval, the second correlation signal being a second correlation value within a sampling interval, the first correlation value corresponding to a correlation between the binary signal and a first reference signal with a frequency substantially identical to a base frequency of a subcarrier of the infrared signal, the second correlation signal corresponding to a correlation between the binary signal and a second reference signal with a phase that differ from a phase of the first reference signal by 90 degrees; and

binarizing the correlation signal generated by the generating and outputting the binarized correlation signal as a decode signal.