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Patent US5361047A successfully refreshed from Google Patents.
US5361047A
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PI/4 shift QPSK modulator and communication apparatus used therewith
Assignee: Hitachi Ltd
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Filing: 1993-05-05
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Granted: 1994-11-01
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Expires: 2013-05-05
Abstract
Abstract A pi /4 shift QPSK modulator for receiving digital signals and for outputting a modulated signal therefrom in accordance with each of the inputted digital signals. The pi /4 QPSK modulator is utilized in a communication apparatus and includes a counter for counting the number of the inputted digital signals, a phase information arithmetic unit for receiving a value of an output from the counter and a value of each of the inputted digital signals for outputting phase information of the signal to be modulated, an arithmetic unit for performing an arithmetic operation on values representing an impulse response of the output phase information from the phase information arithmetic unit and outputting impulse response values in accordance therewith, and an accumulating unit for accumulating impulse response values outputted from the arithmetic unit and for performing an arithmetic operation for enabling generation of a pi /4 shift QPSK modulated signal.
Inventors
- 👤 Yasuaki Takahara
- 👤 Tomohiro Esaki
- 👤 Shigeyuki Sudo
- 👤 Teiji Okamoto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 20:50
CPC Classifications
H; H04; H04L; H04L27/00; H04L27/18; H04L27/20; H04L27/2032; H04L27/2092
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
120 words
A π/4 shift QPSK modulator which receives a digital input signal and outputs a modulated signal based on the input signal, comprising: counting means for counting the number of the input signals and providing an output indicative thereof; phase information arithmetic means for receiving the output from said counting means and a value of the input signal and for producing phase information based upon the output of said counting means and said value of said input signal; arithmetic means for computing the impulse response of said phase information; accumulating means for accumulating the impulse response values produced by said arithmetic means and providing an output signal thereof; and output control means for controlling the output signal of the accumulating means.
Claim 2
Dependent Claim
120 words
A π/4 shift QPSK modulator which receives a digital input signal and outputs a modulated signal based on the input signal, comprising: counting means for counting the number of the input signals and providing an output indicative thereof; phase information arithmetic means for receiving the output from said counting means and a value of the input signal and for producing phase information based upon the output of said counting means and said value of said input signal; arithmetic means for computing the impulse response of said phase information; accumulating means for accumulating the impulse response values produced by said arithmetic means and providing an output signal thereof; and output control means for controlling the output signal of the accumulating means.
Claim 3
Dependent Claim
45 words
A π/4 shift QPSK modulator according to claim 1, wherein said phase information arithmetic means includes: storage means; and address arithmetic means for performing an arithmetic operation on address information in said storage means based on the information input to said phase information arithmetic means.
Claim 4
Dependent Claim
35 words
A π/4 shift QPSK modulator according to claim 1, further comprising: control signal input means for inputting a control signal; and counting control means for resetting said counting means in accordance with said control signal.
Claim 5
Dependent Claim
46 words
A π/4 shift QPSK modulator according to claim 1, wherein said arithmetic means includes storage means which store computed values obtained by multiplying said impulse response value with gain coefficients and which outputs the computed data stored at the address appointed by said output control means.
Claim 6
Dependent Claim
18 words
A π/4 shift QPSK modulator according to claim 1 or 4, wherein said arithmetic means includes a ROM.
Claim 7
Dependent Claim
90 words
A π/4 shift QPSK modulator according to claim 1, wherein said arithmetic means includes: storage means which store computed values obtained by multiplying said impulse response value with gain coefficients; and numerical value converting means for effecting inversion of the sign of the computed data from said storage means or replacement of said computed data with a previously set value, in accordance with a signal input to said arithmetic means; whereby the computed data stored at the address appointed by said output control means is output from said arithmetic means.
Claim 8
Dependent Claim
49 words
A π/4 shift QPSK modulator according to claim 4 or 6, wherein said storage means stores computed values obtained by multiplying said impulse response value with gain coefficients which are a series of function values for determining at least the rise and/or fall waveform of the transmission output power.
Claim 9
Dependent Claim
146 words
A π/4 shift QPSK modulator which receives a digital input signal and outputs a modulated signal based upon the input signal, comprising: counting means for counting the number of the input signals and providing an output indicative thereof; phase information arithmetic means for receiving the output from said counting means and a value of the input signal and for producing phase information based upon the output of said counting means and said value of said input signal; arithmetic means for computing the impulse response of said phase information; accumulating means for accumulating the impulse response values produced by said arithmetic means and providing an output signal; output control means for setting gain coefficients for controlling the amplitude of the output signal of said accumulating means; and multiplier means for multiplying the output signal of said accumulating means with gain coefficients set by said output control means.
Claim 10
Dependent Claim
146 words
A π/4 shift QPSK modulator which receives a digital input signal and outputs a modulated signal based upon the input signal, comprising: counting means for counting the number of the input signals and providing an output indicative thereof; phase information arithmetic means for receiving the output from said counting means and a value of the input signal and for producing phase information based upon the output of said counting means and said value of said input signal; arithmetic means for computing the impulse response of said phase information; accumulating means for accumulating the impulse response values produced by said arithmetic means and providing an output signal; output control means for setting gain coefficients for controlling the amplitude of the output signal of said accumulating means; and multiplier means for multiplying the output signal of said accumulating means with gain coefficients set by said output control means.
Claim 11
Dependent Claim
45 words
A π/4 shift QPSK modulator according to claim 8, wherein said phase information arithmetic means includes: storage means; and address arithmetic means for performing an arithmetic operation on address information in said storage means based on the information input to said phase information arithmetic means.
Claim 12
Dependent Claim
16 words
A π/4 shift QPSK modulator according to claim 8, wherein said arithmetic means includes a ROM.
Claim 13
Dependent Claim
35 words
A π/4 shift QPSK modulator according to claim 8, further comprising: control signal input means for inputting a control signal; and counting control means for resetting said counting means in accordance with said control signal.
Claim 14
Dependent Claim
113 words
A π/4 shift QPSK modulator according to claim 8, wherein said output control means includes: first storage means which stores the gain coefficient of the output signal for the ordinary transmission output operation; second storage means for storing, as gain coefficients, a series of function values which specify the waveform of the rise and/or the fall of the transmission output power for the starting and/or terminating transmission; reading means for successively reading the series of function values from said second storage means; and output change-over means for effecting change-over between the output from said first storage means and the output from said second storage means in accordance with an externally given control output.
Claim 15
Dependent Claim
25 words
A communication system comprising a π/4 shift QPSK modulator as set forth in any one of claims 1 to 4, 6 and 8 to 12.
Claim 16
Dependent Claim
26 words
A π/4 shift QPSK modulator according to claim 1, wherein said output control means controls an output level of the output signal of said accumulating means.
Claim 17
Dependent Claim
26 words
A π/4 shift QPSK modulator according to claim 1, wherein said output control means controls an offset level of the output signal from said accumulating means.
References Cited (Backward Citations)
US4327439A
Cited
US4962510A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-10-31 | 1998-05-02 | 1998-11-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-10-31 | 2002-05-02 | 2002-11-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-10-31 | 2006-05-02 | 2006-11-01 | $7700.00 | Window Closed / Lapsed |