Reception apparatus and reception method

• US 8,081,943 B2
• Filed: 11/21/2008
• Issued: 12/20/2011
• Est. Priority Date: 12/01/2003
• Status: Active Grant

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Shimizu, Yoshito, Watanabe, Takeaki, Saito, Noriaki
• Primary Examiner(s): Tran, Pablo
• Application Number:
  US12/276,047
• Publication Number:
  US 20090080571A1
• Time in Patent Office: 1,124 Days
• Field of Search: 455/244.1, 455/241.1, 455/232.1, 455/253.1, 455/130, 455/226.1, 455/227, 455/230, 455/231, 455/234.2, 455/240.1, 4552421-2422, 455/245.1, 455/252.1, 455/307, 455333-334, 455/341
• US Class Current: 455/244.1
• CPC Class Codes: H04B 1/30 for homodyne or synchrodyne receivers demodulator circuits H03D1/22

Abstract

A receiving apparatus includes an amplification section that amplifies a received signal and a frequency conversion section that converts a frequency of the received signal, from a radio frequency to a baseband, the baseband having a lower frequency than the radio frequency. A gain control section amplifies, by a predetermined gain, the signal that has been subjected to the frequency conversion to the baseband. A voltage calibration section performs calibration on an offset voltage generated in the signal subjected to frequency conversion to the baseband. A time constant control section sets a first time constant during a reception operation and sets a second time constant, which is reduced with respect to the first time constant, during the calibration. A filter section passes a received signal of a predetermined band, with the first time constant or the second time constant, an operation control section stops operation of the amplification section during the calibration, controls the amplification section to operate during the reception operation, and controls the operation of the amplification section so as to reduce a residual offset voltage caused by switching the operation of the amplification section.

Claims

1. A receiving apparatus comprising:

an amplification section that amplifies a received signal;

a frequency conversion section that converts a frequency of the received signal, amplified by the amplification section, from a radio frequency to a baseband, the baseband having a lower frequency than the radio frequency;

a gain control section that amplifies, by a predetermined gain, the received signal, subjected to the frequency conversion to the baseband, by the frequency conversion section;

a voltage calibration section that performs calibration processing on an offset voltage generated in the received signal subjected to frequency conversion to the baseband by the frequency conversion section;

a time constant control section that sets a first time constant during a reception operation and sets a second time constant, which is reduced with respect to the first time constant, during the calibration processing;

a filter section that passes a received signal of a predetermined band with the first time constant or the second time constant; and

an operation control section that stops an operation of the amplification section during the calibration processing and controls the amplification section to operate during the reception operation, and controls the operation of the amplification section so as to reduce a residual offset voltage caused by switching the operation of the amplification section.

2. The receiving apparatus according to claim 1, wherein:

the amplification section is provided per received signal in a plurality of different bands and performs amplification processing for the different bands; and

the operation control section, during the calibration processing of the received signal subjected to frequency conversion to the baseband by the frequency conversion section, the operation control section stops the operation of the amplification section used for amplification of the received signal, in the band being subjected to reception processing, and reduces the offset voltage by performing switching so as to cause the amplification section used for amplification of the received signal, in the band not being subjected to reception processing, to operate.

3. The receiving apparatus according to claim 2, wherein the operation control section cause the amplification section used for amplification of the received signal in the band not used in a proximity cell to operate during the calibration processing.

4. The receiving apparatus according to claim 2, further comprising a storage section that stores first selection information which associates a band with the amplification section,

wherein the operation control section selects the amplification section to be stopped and the amplification section to be operated, with reference to the first selection information using information on the band reported from a communicating party.

5. The receiving apparatus according to claim 2, further comprising a storage section that stores second selection information which associates position information, the band with the amplification section,

wherein the operation control section selects the amplification section to be stopped and the amplification section to be operated, with reference to the second selection information using the position information indicating a position of the receiving apparatus.

6. The receiving apparatus according to claim 1, wherein:

the operation control section stops operation of the amplification section during the calibration processing, when the gain, upon amplification of the received signal by the gain control section, is equal to or more than a threshold value; and

the operation control section performs switching so as to cause the amplification section to operate during the calibration processing, when the gain, upon amplification of the received signal by the gain control section, is less than the threshold value.

7. The receiving apparatus according to claim 1, further comprising a detection section that detects a level of received power of the received signal subjected to frequency conversion to the baseband by the frequency conversion section, wherein:

the operation control section stops operation of the amplification section during the calibration processing, when the level of the received power detected by the detection section is equal to or more than a threshold value; and

the operation control section reduces the offset voltage by performing switching so as to cause the amplification section to operate during the calibration processing, when the level of the received power detected by the detection section is less than the threshold value.