US5696792A
Expired / Lapsed
US
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Digital radiocommunication terminal
Assignee: Hitachi Ltd
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Filing: 1994-12-15
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Granted: 1997-12-09
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Expires: 2014-12-15
Abstract
Abstract The number of oscillators required to construct a digital radiocommunication terminal can be reduced and a circuit used for the digital radiocommunication terminal can be reduced in size. For this purpose, the digital radiocommunication terminal for effecting information transmission using an N (integer)-phase-shift-keyed signal (identification symbol number N=4 upon pi /4 shifted QPSK modulation), is constructed such that an oscillation frequency generated from a reference oscillator employed with a frequency synthesizer is selected to have a common multiple of a second intermediate frequency and an identification symbol phase N and is supplied to a detector for outputting received data therefrom.
Inventors
- 👤 Shigeyuki Sudo
- 👤 Yasuaki Takahara
- 👤 Katsumi Takeda
- 👤 Jun Yamada
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 05:27
CPC Classifications
H; H04; H04L; H04L27/00; H04L27/18; H03; H03D; H03D7/00; H03D7/16; H03D7/161; H03D7/163; H04B; H04B1/00; H04B1/38; H04B1/40; H04B1/403; H04B1/406
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
171 words
A digital radiocommunication terminal for effecting information transmission using an N-phase-shift-keyed signal by N-symbols (where N: integer), comprising: a reference frequency oscillator; frequency synthesize means for multiplying an oscillation output generated from said reference frequency oscillator by a predetermined number; first frequency converting means for generating a first intermediate-frequency band signal from an output generated from said frequency synthesize means and a received N-phase-shift-keyed signal; first intermediate frequency filtering means for effecting a band restriction on an output produced from said first frequency converting means; a local oscillator; second frequency converting means for generating a second intermediate-frequency band signal from an output produced from said local oscillator and an output produced from said first intermediate frequency filtering means; amplifying means for amplifying said second intermediate-frequency band signal; and detecting means for detecting a modulated phase angle from a signal outputted from said amplifying means; the oscillation output frequency generated from said reference frequency oscillator means being held set to a common multiple of the N symbols and the second intermediate frequency.
Claim 2
Dependent Claim
171 words
A digital radiocommunication terminal for effecting information transmission using an N-phase-shift-keyed signal by N-symbols (where N: integer), comprising: a reference frequency oscillator; frequency synthesize means for multiplying an oscillation output generated from said reference frequency oscillator by a predetermined number; first frequency converting means for generating a first intermediate-frequency band signal from an output generated from said frequency synthesize means and a received N-phase-shift-keyed signal; first intermediate frequency filtering means for effecting a band restriction on an output produced from said first frequency converting means; a local oscillator; second frequency converting means for generating a second intermediate-frequency band signal from an output produced from said local oscillator and an output produced from said first intermediate frequency filtering means; amplifying means for amplifying said second intermediate-frequency band signal; and detecting means for detecting a modulated phase angle from a signal outputted from said amplifying means; the oscillation output frequency generated from said reference frequency oscillator means being held set to a common multiple of the N symbols and the second intermediate frequency.
Claim 3
Dependent Claim
53 words
The digital radiocommunication terminal as claimed in claim 1, wherein said detecting means has means for generating a differential detection reference signal obtained by time-delaying a phase angle of said received N-phase-shift-keyed signal and phase-lag detecting means for detecting a phase lag between said differential detection reference signal and said received N-phase-shift-keyed signal.
Claim 4
Dependent Claim
57 words
The digital radiocommunication terminal as claimed in claim 2, wherein said phase-lag detecting means includes means for generating a gate pulse corresponding to a phase lag between said differential detection reference signal and said received N-phase-shift-keyed signal and means for counting the width of the gate pulse based on the oscillation output of said reference frequency oscillator.
Claim 5
Dependent Claim
58 words
The digital radiocommunication terminal as claimed in claim 2, wherein the oscillation output frequency of said reference frequency oscillator and the second intermediate frequency are set as 12.6 MHz and 450 kHz, respectively, and said phase-lag detecting means operates to perform phase quantization with an accuracy equal to dividing one wavelength of 450 kHz into 28 equal parts.
Claim 6
Dependent Claim
35 words
The digital radiocommunication terminal as claimed in claim 1, wherein the oscillation output frequency of said reference frequency oscillator is further set to an integral multiple of a symbol transfer rate of the N-phase-shift-keyed signal.
Claim 7
Dependent Claim
45 words
The digital radiocommunication terminal as claimed in claim 5, further including: waveform generating means for generating waveforms of vector signals corresponding to signals identical and orthogonal in phase to the N-phase-shift-keyed signal; and orthogonal modulating means for modulating a transmit frequency using the vector signals.
Claim 8
Dependent Claim
61 words
The digital radiocommunication terminal as claimed in claim 6, wherein said waveform generating means comprises: digital filter means for implementing a filter operation for Nyquist transmission by digital arithmetic processing and for generating quantized waveform data of a filter output; and digital-to-analog converting means for converting the quantized waveform data into an analog signal waveform and outputting the converted waveform therefrom.
Claim 9
Dependent Claim
34 words
The digital radiocommunication terminal as claimed in claim 7, wherein an oversampling clock signal per symbol of the waveform data is obtained by frequency-dividing the oscillation output produced from said reference frequency oscillator means.
Claim 10
Dependent Claim
58 words
The digital radiocommunication terminal as claimed in claim 1, wherein the oscillation output of said frequency synthesize means is set so as to become higher than the frequency of the received N-phase-shift-keyed signal and the output frequency of said local oscillator is set so as to become lower than the output frequency of said first intermediate-frequency filtering means.
Claim 11
Dependent Claim
110 words
A digital radiocommunication device for converting N-phase-shift-keyed received signal in respective conversions into first and second intermediate frequencies and for detecting a modulated phase angle from the result of the second intermediate frequency conversion, comprising: reference frequency oscillation means having an oscillation frequency corresponding to a common multiple of the N phase and the second intermediate frequency; means for effecting the first intermediate-frequency conversion based on a frequency signal obtained by multiplying the oscillation frequency signal produced from said reference frequency oscillation means by a number; and means for detecting said modulated phase angle with the oscillation frequency signal produced from said reference frequency oscillation means as a reference signal.
Claim 12
Dependent Claim
110 words
A digital radiocommunication device for converting N-phase-shift-keyed received signal in respective conversions into first and second intermediate frequencies and for detecting a modulated phase angle from the result of the second intermediate frequency conversion, comprising: reference frequency oscillation means having an oscillation frequency corresponding to a common multiple of the N phase and the second intermediate frequency; means for effecting the first intermediate-frequency conversion based on a frequency signal obtained by multiplying the oscillation frequency signal produced from said reference frequency oscillation means by a number; and means for detecting said modulated phase angle with the oscillation frequency signal produced from said reference frequency oscillation means as a reference signal.
Claim 13
Dependent Claim
82 words
The digital radiocommunication device as claimed in claim 10, wherein the frequency of the oscillation frequency signal generated from said reference frequency oscillating means is an integral multiple of a symbol transfer rate of the N-phase-shift-keyed signal, and further including vector signal generating means for generating vector signals corresponding to signals identical and orthogonal in phase to the N-phase-shift-keyed signal with a frequency signal obtained by frequency-dividing the oscillation frequency signal produced from said reference frequency oscillation means as a reference signal.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2000-12-08 | 2001-06-09 | 2001-12-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-12-08 | 2005-06-09 | 2005-12-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-12-08 | 2009-06-09 | 2009-12-09 | $7700.00 | Window Closed / Lapsed |