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US5057786A
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Quadrature amplitude modulation wave demodulator provided with band-pass filters for fixed equalizer
Assignee: Sharp Corp
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Filing: 1990-06-20
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Granted: 1991-10-15
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Expires: 2010-06-20
Abstract
Abstract A quadrature amplitude modulation wave demodulator which includes a fixed equalizer having a first band-pass filter applied with a quadrature amplitude modulation wave reception signal for outputting an in-phase component with respect to a carrier wave for the reception signal, and a second band-pass filter applied with the reception signal for outputting a quadrature component with respect to the carrier wave for the reception signal. There is provided a vector multiplication section for performing vector multiplication between one vector having outputs of the first and second band-pass filters as two components, and another vector having two reference carrier waves in quadrature to each other as two components.
Inventors
- 👤 Syuuichi Yoshikawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 23:12
CPC Classifications
H; H03; H03D; H03D1/00; H03D1/22; H03D1/2245; H03B; H03B28/00; H03D3/00; H03D3/007
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
148 words
A quadrature amplitude modulation wave demodulator comprising: a fixed equalizer having a first band-pass filter for receiving a quadrature amplitude modulation wave reception signal and for outputting an in-phase component with respect to a carrier wave for the reception signal; a second band-pass filter for receiving said reception signal and for outputting a quadrature component with respect to the carrier wave for the reception signal; and each of said first and second band-pass filters having an impulse response, including an impulse response in which an impulse response of a filter for compensating for the characteristics of communication lines and an impulse response of a reception filter are folded; and a vector multiplication section for performing vector multiplication between one vector having outputs of said first and second band-pass filters as two components, and another vector having two reference carrier waves in quadrature to each other as two components.
Claim 2
Dependent Claim
148 words
A quadrature amplitude modulation wave demodulator comprising: a fixed equalizer having a first band-pass filter for receiving a quadrature amplitude modulation wave reception signal and for outputting an in-phase component with respect to a carrier wave for the reception signal; a second band-pass filter for receiving said reception signal and for outputting a quadrature component with respect to the carrier wave for the reception signal; and each of said first and second band-pass filters having an impulse response, including an impulse response in which an impulse response of a filter for compensating for the characteristics of communication lines and an impulse response of a reception filter are folded; and a vector multiplication section for performing vector multiplication between one vector having outputs of said first and second band-pass filters as two components, and another vector having two reference carrier waves in quadrature to each other as two components.
Claim 3
Dependent Claim
29 words
The quadrature amplitude modulation wave demodulator of claim 1, further including a reference carrier wave generator operatively connected to the vector multiplication section for supplying the reference carrier waves.
Claim 4
Dependent Claim
28 words
The quadrature amplitude modulation wave demodulator according to claim 2 further including π/2 phase shifter operatively connected between said reference carrier wave generator and said vector multiplying section.
Claim 5
Dependent Claim
159 words
An quadrature amplitude modulation wave demodulator for use with a modem comprising: a fixed equalizer having a first band-pass for receiving a quadrature amplitude modulation wave reception signal for outputting an in-phase component with respect to a carrier wave for the reception signal; a second band-pass filter for receiving said reception signal and for outputting a quadrature component with respect to the carrier wave for the reception signal; each of said first and second band-pass filters having an impulse response including an impulse response in which an impulse response of a filter for compensating for the characteristics of communication lines and an impulse response of a reception filter are folded; a vector multiplication section for performing vector multiplication between one vector having outputs of said first and second band-pass filters as two components, and another vector having two reference carrier waves in quadrature to each other as two components; and a modem operatively connected to said vector multiplication section.
Claim 6
Dependent Claim
159 words
An quadrature amplitude modulation wave demodulator for use with a modem comprising: a fixed equalizer having a first band-pass for receiving a quadrature amplitude modulation wave reception signal for outputting an in-phase component with respect to a carrier wave for the reception signal; a second band-pass filter for receiving said reception signal and for outputting a quadrature component with respect to the carrier wave for the reception signal; each of said first and second band-pass filters having an impulse response including an impulse response in which an impulse response of a filter for compensating for the characteristics of communication lines and an impulse response of a reception filter are folded; a vector multiplication section for performing vector multiplication between one vector having outputs of said first and second band-pass filters as two components, and another vector having two reference carrier waves in quadrature to each other as two components; and a modem operatively connected to said vector multiplication section.
Claim 7
Dependent Claim
18 words
The amplitude modulation wave demodulator of claim 4, wherein said modem includes a first and second data detector.
Claim 8
Dependent Claim
46 words
The amplitude modulation wave demodulator of claim 5 wherein said first and second data detector are operatively connected to a first and second adder of the multiplication section; and said modem includes a first and second adder operatively connected to said first and second data detector.
Claim 9
Dependent Claim
34 words
The amplitude modulation wave demodulator of claim 6, wherein said modem includes a carrier wave detector operatively connected to said first and second adders of the modem and to a reference carrier wave generator.
References Cited (Backward Citations)
US4849706A
Cited
US4871974A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-10-14 | 1995-04-15 | 1995-10-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-10-14 | 1999-04-15 | 1999-10-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-10-14 | 2003-04-15 | 2003-10-15 | $7700.00 | Window Closed / Lapsed |