Patent US6236690B1 successfully refreshed from Google Patents.
US6236690B1
Expired / Lapsed
US
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Direct-conversion receiver for digital-modulation signal
Assignee: Panasonic Intellectual Property Corp of America
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Filing: 1999-06-14
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Granted: 2001-05-22
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Expires: 2019-06-14
Abstract
Abstract A direct-conversion receiver includes a local oscillator for generating a local oscillator signal, a converter circuit for converting a received radio signal into a pair of a baseband I signal and a baseband Q signal in response to the local oscillator signal, a demodulator for demodulating the pair of the baseband I signal and the baseband Q signal into a demodulation-resultant signal which is neither an I signal nor a Q signal, a detector circuit for detecting a difference between a frequency of the local oscillator signal and a frequency of a carrier of the received radio signal, a clock signal generator for generating a first clock signal providing a timing which corresponds to a center of a symbol period, a signal delay device for delaying the first clock signal to provide a second clock signal, and a symbol deciding circuit for deciding a logic state of the demodulation-resultant signal at a timing determined by the second clock signal.
Inventors
- 👤 Masahiro Mimura
- 👤 Makoto Hasegawa
- 👤 Katsushi Yokozaki
- 👤 Hiroyuki Harada
- 👤 Takaaki Kishigami
- 👤 Yasunari Tanaka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 06:24
CPC Classifications
H; H04; H04B; H04B1/00; H04B1/06; H04B1/16; H04B1/30; H03; H03D; H03D3/00; H03D3/007; H04B17/00; H04B17/30; H04B17/309; H04B17/318
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
165 words
A direct-conversion receiver comprising: a local oscillator for generating a local oscillator signal; means for converting a received radio signal into a pair of a baseband I signal and a baseband Q signal in response to the local oscillator signal; a demodulator for demodulating the pair of the baseband I signal and the baseband Q signal into a demodulation-resultant signal which is neither an I signal nor a Q signal; means for detecting a difference between a frequency of the local oscillator signal and a frequency of a carrier of the received radio signal; a clock signal generator for generating a first clock signal providing a timing which corresponds to a center of a symbol period; a signal delay device for delaying the first clock signal in response to the detected frequency difference, and thereby converting the first clock signal into a second clock signal; and means for deciding a logic state of the demodulation-resultant signal at a timing determined by the second clock signal.
Claim 2
Dependent Claim
165 words
A direct-conversion receiver comprising: a local oscillator for generating a local oscillator signal; means for converting a received radio signal into a pair of a baseband I signal and a baseband Q signal in response to the local oscillator signal; a demodulator for demodulating the pair of the baseband I signal and the baseband Q signal into a demodulation-resultant signal which is neither an I signal nor a Q signal; means for detecting a difference between a frequency of the local oscillator signal and a frequency of a carrier of the received radio signal; a clock signal generator for generating a first clock signal providing a timing which corresponds to a center of a symbol period; a signal delay device for delaying the first clock signal in response to the detected frequency difference, and thereby converting the first clock signal into a second clock signal; and means for deciding a logic state of the demodulation-resultant signal at a timing determined by the second clock signal.
Claim 3
Dependent Claim
193 words
A direct-conversion receiver for a radio signal carrying information, comprising: first means for receiving the radio signal; a local oscillator outputting a signal having a frequency which is designed to correspond to a frequency of a carrier of the radio signal; a phase shifter for shifting a phase of the output signal of the local oscillator by 90°; mixers for mixing the radio signal received by the first means, the output signal of the local oscillator, and an output signal of the phase shifter, and down-converting the radio signal into a pair of a baseband I signal and a baseband Q signal representing the information; a demodulator for demodulating the pair of the baseband I signal and the baseband Q signal into a demodulation-resultant signal which is neither an I signal nor a Q signal; second means for detecting a difference between the frequency of the output signal of the local oscillator and the frequency of the carrier of the radio signal received by the first means; and third means for deciding a logic state of the demodulation-resultant signal at a timing which depends on the frequency difference detected by the second means.
Claim 4
Dependent Claim
193 words
A direct-conversion receiver for a radio signal carrying information, comprising: first means for receiving the radio signal; a local oscillator outputting a signal having a frequency which is designed to correspond to a frequency of a carrier of the radio signal; a phase shifter for shifting a phase of the output signal of the local oscillator by 90°; mixers for mixing the radio signal received by the first means, the output signal of the local oscillator, and an output signal of the phase shifter, and down-converting the radio signal into a pair of a baseband I signal and a baseband Q signal representing the information; a demodulator for demodulating the pair of the baseband I signal and the baseband Q signal into a demodulation-resultant signal which is neither an I signal nor a Q signal; second means for detecting a difference between the frequency of the output signal of the local oscillator and the frequency of the carrier of the radio signal received by the first means; and third means for deciding a logic state of the demodulation-resultant signal at a timing which depends on the frequency difference detected by the second means.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2004-05-21 | 2004-11-20 | 2005-05-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2008-05-21 | 2008-11-20 | 2009-05-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2012-05-21 | 2012-11-20 | 2013-05-22 | $7700.00 | Window Closed / Lapsed |