US5657313A
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US
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Signal transmitting apparatus and signal receiving apparatus using orthogonal frequency division multiplexing
Assignee: JVCKenwood Corp
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Filing: 1995-08-11
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Granted: 1997-08-12
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Expires: 2015-08-11
Abstract
Abstract A signal transmitting apparatus using orthogonal frequency division multiplexing includes an inverse fast Fourier transform circuit for converting a digital information signal into a first multi-value QAM modulation signal. A guard interval setting circuit is operative for periodically generating a guard interval signal equal to a time segment of the first multi-value QAM modulation signal, and inserting the guard interval signal into the first multi-value QAM modulation signal to convert the first multi-value QAM modulation signal into a second multi-value QAM modulation signal. A clock signal generating circuit is operative for generating a first clock signal which drives the inverse fast Fourier transform circuit, and generating a second dock signal which drives the guard interval setting circuit. The inverse fast Fourier transform circuit includes a device for generating a pilot signal which corresponds to a given-order carrier, and adding the pilot signal to the first multi-value QAM modulation signal. The pilot signal has a predetermined frequency and an angle modulation component which remains constant over a plurality of symbol periods. The pilot signal corresponding to a given integer times its wavelength or a given odd number times its half wavelength is present in a guard interval occupied by the guard interval signal in the second multi-value QAM modulation signal. The pilot signal is continuously present over the guard interval and another interval.
Inventors
- 👤 Nobuaki Takahashi
- 👤 Susumu Takahashi
- 👤 Kenji Sugiyama
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 11:57
CPC Classifications
H; H04; H04L; H04L27/00; H04L27/26; H04L27/2601; H04L27/2647; H04L27/2655; H04L27/2662; H04L27/2602; H04L27/2657; H04L27/2668; H04L27/2673; H04L27/2675
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
223 words
A signal transmitting apparatus using orthogonal frequency division multiplexing, comprising: an inverse fast Fourier transform circuit for converting a digital information signal into a first multi-value QAM modulation signal; a guard interval setting circuit for periodically generating a guard interval signal equal to a time segment of the first multi-value QAM modulation signal, and inserting the guard interval signal into the first multi-value QAM modulation signal to convert the first multi-value QAM modulation signal into a second multi-value QAM modulation signal; and a clock signal generating circuit for generating a first clock signal which drives the inverse fast Fourier transform circuit, and generating a second clock signal which drives the guard interval setting circuit; wherein the inverse fast Fourier transform circuit comprises means for generating a pilot signal which corresponds to a given-order carrier, and adding the pilot signal to the first multi-value QAM modulation signal, wherein the pilot signal has a predetermined frequency and an angle modulation component which remains constant over a plurality of symbol periods, wherein the pilot signal corresponding to a given integer times its wavelength or a given odd number times its half wavelength is present in a guard interval occupied by the guard interval signal in the second multi-value QAM modulation signal, and wherein the pilot signal is continuously present over the guard interval and another interval.
Claim 2
Dependent Claim
223 words
A signal transmitting apparatus using orthogonal frequency division multiplexing, comprising: an inverse fast Fourier transform circuit for converting a digital information signal into a first multi-value QAM modulation signal; a guard interval setting circuit for periodically generating a guard interval signal equal to a time segment of the first multi-value QAM modulation signal, and inserting the guard interval signal into the first multi-value QAM modulation signal to convert the first multi-value QAM modulation signal into a second multi-value QAM modulation signal; and a clock signal generating circuit for generating a first clock signal which drives the inverse fast Fourier transform circuit, and generating a second clock signal which drives the guard interval setting circuit; wherein the inverse fast Fourier transform circuit comprises means for generating a pilot signal which corresponds to a given-order carrier, and adding the pilot signal to the first multi-value QAM modulation signal, wherein the pilot signal has a predetermined frequency and an angle modulation component which remains constant over a plurality of symbol periods, wherein the pilot signal corresponding to a given integer times its wavelength or a given odd number times its half wavelength is present in a guard interval occupied by the guard interval signal in the second multi-value QAM modulation signal, and wherein the pilot signal is continuously present over the guard interval and another interval.
Claim 3
Dependent Claim
20 words
The signal transmitting apparatus of claim 1, wherein the first dock signal and the second clock signal are the same.
Claim 4
Dependent Claim
33 words
The signal transmitting apparatus of claim 1, wherein a ratio between the frequency of the pilot signal and a frequency of the first clock signal is equal to a ratio between predetermined integers.
Claim 5
Dependent Claim
228 words
A signal transmitting apparatus using orthogonal frequency division multiplexing, comprising: an inverse fast Fourier transform circuit for converting a digital information signal into a first multi-value QAM modulation signal; a guard interval setting circuit for periodically generating a guard interval signal equal to a time segment of the first multi-value QAM modulation signal, and inserting the guard interval signal into the first multi-value QAM modulation signal to convert the first multi-value QAM modulation signal into a second multi-value QAM modulation signal; and a clock signal generating circuit for generating a first clock signal which drives the inverse fast Fourier transform circuit, and generating a second clock signal which drives the guard interval setting circuit; wherein the inverse fast Fourier transform circuit comprises means for generating a pilot signal which corresponds to a given-order carrier, and adding the pilot signal to the first multi-value QAM modulation signal, wherein the pilot signal has a predetermined frequency and an angle modulation component which remains constant over a plurality of symbol periods, wherein the pilot signal corresponding to a given integer times its wavelength or a given odd number times its half wavelength is present in a guard interval occupied by the guard interval signal in the second multi-value QAM modulation signal, and wherein time segments of the pilot signal in two adjacent symbol periods have an inverted relation with each other.
Claim 6
Dependent Claim
228 words
A signal transmitting apparatus using orthogonal frequency division multiplexing, comprising: an inverse fast Fourier transform circuit for converting a digital information signal into a first multi-value QAM modulation signal; a guard interval setting circuit for periodically generating a guard interval signal equal to a time segment of the first multi-value QAM modulation signal, and inserting the guard interval signal into the first multi-value QAM modulation signal to convert the first multi-value QAM modulation signal into a second multi-value QAM modulation signal; and a clock signal generating circuit for generating a first clock signal which drives the inverse fast Fourier transform circuit, and generating a second clock signal which drives the guard interval setting circuit; wherein the inverse fast Fourier transform circuit comprises means for generating a pilot signal which corresponds to a given-order carrier, and adding the pilot signal to the first multi-value QAM modulation signal, wherein the pilot signal has a predetermined frequency and an angle modulation component which remains constant over a plurality of symbol periods, wherein the pilot signal corresponding to a given integer times its wavelength or a given odd number times its half wavelength is present in a guard interval occupied by the guard interval signal in the second multi-value QAM modulation signal, and wherein time segments of the pilot signal in two adjacent symbol periods have an inverted relation with each other.
Claim 7
Dependent Claim
20 words
The signal transmitting apparatus of claim 4, wherein the first clock signal and the second clock signal are the same.
Claim 8
Dependent Claim
33 words
The signal transmitting apparatus of claim 4, wherein a ratio between the frequency of the pilot signal and a frequency of the first clock signal is equal to a ratio between predetermined integers.
Claim 9
Dependent Claim
158 words
A signal receiving apparatus using orthogonal frequency division multiplexing, comprising: first means for reproducing a pilot signal from a multi-value QAM modulation signal by angle demodulation, wherein the pilot signal has a predetermined frequency and an angle modulation component which remains constant over a plurality of symbol periods, wherein the pilot signal corresponding to a given integer times its wavelength or a given odd number times its half wavelength is present in a guard interval occupied by a guard interval signal in the multi-value QAM modulation signal, and wherein the pilot signal is continuously present over the guard interval and another interval; second means for converting a frequency of the reproduced pilot signal to change the reproduced pilot signal into a clock signal; and a fast Fourier transform circuit for converting the multi-value QAM modulation signal into a digital information signal; wherein the fast Fourier transform circuit is driven by the clock signal generated by the second means.
Claim 10
Dependent Claim
158 words
A signal receiving apparatus using orthogonal frequency division multiplexing, comprising: first means for reproducing a pilot signal from a multi-value QAM modulation signal by angle demodulation, wherein the pilot signal has a predetermined frequency and an angle modulation component which remains constant over a plurality of symbol periods, wherein the pilot signal corresponding to a given integer times its wavelength or a given odd number times its half wavelength is present in a guard interval occupied by a guard interval signal in the multi-value QAM modulation signal, and wherein the pilot signal is continuously present over the guard interval and another interval; second means for converting a frequency of the reproduced pilot signal to change the reproduced pilot signal into a clock signal; and a fast Fourier transform circuit for converting the multi-value QAM modulation signal into a digital information signal; wherein the fast Fourier transform circuit is driven by the clock signal generated by the second means.
Claim 11
Dependent Claim
163 words
A signal receiving apparatus using orthogonal frequency division multiplexing, comprising: first means for reproducing a pilot signal from a multi-value QAM modulation signal by angle demodulation, wherein the pilot signal has a predetermined frequency and an angle modulation component which remains constant over a plurality of symbol periods, wherein the pilot signal corresponding to a given integer times its wavelength or a given odd number times its half wavelength is present in a guard interval occupied by a guard interval signal in the multi-value QAM modulation signal, and wherein time segments of the pilot signal in two adjacent symbol periods have an inverted relation with each other; second means for converting a frequency of the reproduced pilot signal to change the reproduced pilot signal into a clock signal; and a fast Fourier transform circuit for converting the multi-value QAM modulation signal into a digital information signal; wherein the fast Fourier transform circuit is driven by the clock signal generated by the second means.
Claim 12
Dependent Claim
163 words
A signal receiving apparatus using orthogonal frequency division multiplexing, comprising: first means for reproducing a pilot signal from a multi-value QAM modulation signal by angle demodulation, wherein the pilot signal has a predetermined frequency and an angle modulation component which remains constant over a plurality of symbol periods, wherein the pilot signal corresponding to a given integer times its wavelength or a given odd number times its half wavelength is present in a guard interval occupied by a guard interval signal in the multi-value QAM modulation signal, and wherein time segments of the pilot signal in two adjacent symbol periods have an inverted relation with each other; second means for converting a frequency of the reproduced pilot signal to change the reproduced pilot signal into a clock signal; and a fast Fourier transform circuit for converting the multi-value QAM modulation signal into a digital information signal; wherein the fast Fourier transform circuit is driven by the clock signal generated 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) | 2000-08-11 | 2001-02-10 | 2001-08-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-08-11 | 2005-02-10 | 2005-08-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-08-11 | 2009-02-10 | 2009-08-12 | $7700.00 | Window Closed / Lapsed |