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31. 发明专利

JPH09214576A DEMODULATION CIRCUIT 失效
公开(公告)号：JPH09214576A
公开(公告)日：1997-08-15
申请号：JP2225596
申请日：1996-02-08
申请人： NIPPON TELEGRAPH & TELEPHONE
发明人： KOBAYASHI SEI , KUBOTA SHUJI
IPC分类号： H04L27/14 , H04L27/227
摘要： PROBLEM TO BE SOLVED: To provide a demodulation circuit with an excellent code error rate characteristic by providing a delay means, a 1st detection means, a carrier recovery means, a 2nd detection means, a soft discrimination differential decoding means, an addition synthesis means and a discrimination means. SOLUTION: A reception signal (a) is orthogonally detected by an orthogonal detection circuit 1 into a complex base band signal (b) and converted into a phase signal (c) by a phase detection circuit 3. A delay circuit 11 delays the signal (c) and provides an output of a delay signal (d) and a carrier recovery circuit 21 eliminates modulation components of the signal (c) and provides an output of a carrier signal (g). A subtractor circuit 10 conducts arithmetic operation of (c-d) and provides an output of a phase change (e). A subtractor circuit 20 being a 2nd detection means conducts arithmetic operation of (c-g) and provides an output of a phase difference (h) of reception signal phases. A soft discrimination differential coding means has a soft discrimination differential decoding circuit 23 and a code soft discrimination circuit 22. The circuit 22 applies soft discrimination to the output of the circuit 20 and the circuit 23 provides an output of a synchronization detection output (i), and a discrimination circuit 31 discriminates a phase (j) being an output of an adder 30 and provides an output of a reception signal (f).

32. 发明专利

JPH0879323A CLOCK PHASE DETECTION CIRCUIT 失效
公开(公告)号：JPH0879323A
公开(公告)日：1996-03-22
申请号：JP20767094
申请日：1994-08-31
申请人： NIPPON TELEGRAPH & TELEPHONE
发明人： KUMAGAI TOMOAKI , KOBAYASHI SEI , KATO SHUZO
IPC分类号： G01R25/00 , H04L7/00 , H04L27/22
摘要： PURPOSE: To obtain a clock phase detection circuit in which a clock phase at a sampling time is detected from a digital modulation signal having only a specific frequency component. CONSTITUTION: A chirp conversion circuit 2 applies chirp-Fourier conversion to a received digital modulation signal, them, the result is outputted to a synthesis circuit 5 via an orthogonal detector 3 and A/D converters 4a, 4b. The synthesis circuit 5 outputs a Fourier transformation signal for one symbol block to a sampling circuit 7 as a Fourier transform signal for plural symbol periods. The sampling circuit 7 applies sampling to the signal in a timing corresponding to a specific two-frequency component and a transformation table 9a detects the phase of the specific two-frequency component and a difference circuit 10 obtains the phase difference of each of phases and the result is outputted to the transformation table 9b. A transformation table 9b outputs a clock phase depending on the phase difference outputted from the difference circuit 10 to a filter 11, which smooths a clock phase signal and outputs a result.

33. 发明专利

JPH0690226A DIVERSITY RECEIVER 失效
公开(公告)号：JPH0690226A
公开(公告)日：1994-03-29
申请号：JP24103492
申请日：1992-09-09
申请人： NIPPON TELEGRAPH & TELEPHONE
发明人： KOBAYASHI SEI , MORIKURA MASAHIRO , KATO SHUZO
IPC分类号： H04B7/08 , H04L1/06
摘要： PURPOSE:To obtain high line quality even without providing a reception signal level detector in a mobile body communication line of remarkably low fading, etc., by smoothing a phase error by a smoothing means, and using a smoothed signal as reference for branch selection. CONSTITUTION:Receivers 3, 4 demodulate the output of antennas 1, 2 and supply demodulated output to a switch 8. The output of the receivers 3, 4 are also inputted to phase error detectors 9, 10, and the phase error detectors 9, 10 detect an error from a normal phase value in the demodulated output, and outputs the absolute value of it. Integrators 12, 13 integrate the phase errors detected by the phase error detectors 9, 10 on time constant (n) symbols. Integrated phase error signals are compared with each other by a comparator 7. The comparator 7 sets the switch 8 so as to output a signal demodulated by the receiver of the branch with a small integrated phase error signal from the switch 8.

34. 发明专利

JPH05167628A INVERSE MODULATION TYPE DEMODULATION CIRCUIT FOR OQPSK 失效
公开(公告)号：JPH05167628A
公开(公告)日：1993-07-02
申请号：JP32845391
申请日：1991-12-12
申请人： NIPPON TELEGRAPH & TELEPHONE
发明人： MATSUMOTO YOICHI , KOBAYASHI SEI , MORIKURA MASAHIRO , KATO SHUZO
IPC分类号： H04L27/227 , H04L27/22
摘要： PURPOSE:To implement correct inverse modulation to a demodulation signal. CONSTITUTION:A demodulation circuit is provided with a quasi-synchronization detection means 11 converting a digital phase modulation signal into a base band signal, a sampling means outputting a first time series date of the sampled base band data a complex multiplier means 23 implementing synchronization detection through complex multiplication between 2nd time series data representing a recovered carrier signal and 1st time series data and outputting 3rd time series data as a demodulation signal, an inverse modulation use signal generating means 29 outputting an OQPSK modulation signal in response to a history of its discriminated value as 4th time series data, an inverse modulation means 25 extracting the recovered carrier signal from the 1st and 4th time series data, filter means 26, 27 reducing the noise component, making the amplitude constant and outputting the result as the 2nd time series data, and an amplitude adjustment means 28.

35. 发明专利

JPH0454045A CARRIER RECOVERY CIRCUIT 失效
公开(公告)号：JPH0454045A
公开(公告)日：1992-02-21
申请号：JP16369790
申请日：1990-06-21
申请人： NIPPON TELEGRAPH & TELEPHONE
发明人： KOBAYASHI SEI , SAKAI TSUTOMU , MORIKURA MASAHIRO , KATO SHUZO
IPC分类号： H04L27/227 , H04L27/22
摘要： PURPOSE:To realize a carrier recovery circuit able to track a high speed phase fluctuation due to rising fading with a small phase slip rate by inputting an extracted carrier component to two kinds of filters whose pass band width differs from each other and using a signal whose phase is an intermediate phase between phases of output signals of the two filters as a reference carrier. CONSTITUTION:An inputted PSK signal is detected by a detector 1 and a modulation phase is discriminated by an identification device 3 and the PSK signal whose timing is adjusted by a delay circuit 2 is subject to inverse modulation at an inverse modulator 4, from which a non-modulation carrier is obtained. The non-modulation carrier is inputted to filters 7, 8. The pass band width of the filter 7 is selected sufficiently smaller than that for a fading frequency and the pass band width of the filter 8 is selected sufficiently larger than that for a fading frequency. Outputs of both filters are made the same amplitude by limiters 9, 10 respectively and they are synthesized by an adder 11. The phase of an output of the adder is made equal to a mean phase of each filter output. The output is fed back to the detector 1 as a recovery carrier.

36. 发明专利

JPH03241925A DIVERSITY RECEPTION CIRCUIT 失效
公开(公告)号：JPH03241925A
公开(公告)日：1991-10-29
申请号：JP3726390
申请日：1990-02-20
申请人： NIPPON TELEGRAPH & TELEPHONE
发明人： KOBAYASHI SEI , SAKAI TSUTOMU , KUBOTA SHUJI , KATO SHUZO
IPC分类号： H04B7/08 , H04L1/02
摘要： PURPOSE:To improve the transmission quality by applying soft discrimination demodulation to each reception signal of each branch and using a weight coefficient obtained from a soft discrimination demodulation signal for each branch to obtain a synthesis signal with weighting and adding reception signals of each branch and applying soft discrimination Viterbi decoding to the synthesis signal. CONSTITUTION:Arithmetic signal sections 13, 14 calculate the mean value of absolute values of soft discrimination signals of a prescribed symbol (N) and the variance. Then a soft discrimination signal inputted to delay circuits 15, 16 is delayed by only N/2 symbol. The timing matching is applied with the processing delay attended with the calculation of the mean value and variance due to the delay and the weight coefficient (W=A/sigma , where W is weight coefficient, A is the mean value and sigma is a variance) with respect to a symbol is obtained from preceding and succeeding N/2 symbols and the accuracy of the maximum ratio synthesis is improved. Thus, the transmission quality is improved.

37. 发明专利

JP2003258752A MULTIRATE GROUP MODEM, MULTIRATE GROUP TRANSMITTER AND RECEIVER, AND TRANSMITTER/RECEIVER 审中-公开
公开(公告)号：JP2003258752A
公开(公告)日：2003-09-12
申请号：JP2002052010
申请日：2002-02-27
申请人： NIPPON TELEGRAPH & TELEPHONE
发明人： TANABE KAZUHIRO , KOBAYASHI SEI , OHATA KOHEI , UEHA MASAZUMI
IPC分类号： H04J1/02
摘要： PROBLEM TO BE SOLVED: To provide a transmitter/receiver in which the number of radio carriers can be flexibly changed as needed by increasing/decreasing modules in a wireless communication system for simultaneously handling a plurality of carriers at different speeds in simple device configuration. SOLUTION: A transmission side is provided with a plurality of multirate group modulation circuits 127-129 for simultaneously modulating a plurality of signals in frequency areas which are not mutually overlapped and further, multirate modulation circuits 130-132 for utilizing frequency areas among the multirate group modulation circuits 127-129. Similarly, a reception side is also provided with multirate group demodulation circuits 526-528 for simultaneously demodulating the plurality of signals modulated variable in the modulation speed and/or variably in the number of carriers without overlapping the frequency areas of a communication channel, and multirate demodulation circuits 529-531 for demodulating signals in the overlapped frequency areas of the communication channel. COPYRIGHT: (C)2003,JPO

38. 发明专利

JP2000244430A SUPERIMPOSED SIGNAL RECEPTION DEVICE 失效
公开(公告)号：JP2000244430A
公开(公告)日：2000-09-08
申请号：JP3937699
申请日：1999-02-18
申请人： NIPPON TELEGRAPH & TELEPHONE
发明人： KOBAYASHI SEI , KAZAMA HIROSHI
IPC分类号： H04B1/69 , H04J1/00 , H04J13/00
摘要： PROBLEM TO BE SOLVED: To provide a device where a high speed modulation signal on a low speed modulation signal transmitted by superimposing it with the high speed modulation signal is removed and the quality of the low speed modulation signal that is not superimposed is not deteriorated by applying the removal of the high speed modulation signal only to the demodulation means of the low speed modulation signal superimposed with the high speed modulation signal. SOLUTION: A demodulation means corresponding to a low speed modulation signal which is not superimposed with a high speed modulation signal demodulates a reception signal and the demodulation means corresponding to the low speed modulation signal superimposed with the high speed modulation signal demodulates the output signal of a synthesis means. In the device, a variable delay unit 701, a variable phase shifter 704 and a variable attenuator 705 adjust the delay time, the phase and the amplitude so that the amplitude of the high speed modulation signal S5 and that of a replica signal r1, which are contained in a repeater output signal, become equal and the phases become opposite. Thus, the high speed modulation signal S5 is removed from the output signal of a synthesizer 706. The low speed modulation signals S1 and S2 are taken out from the output signal of the synthesizer 706 by channel filters 711 and 721.

39. 发明专利

JPH1155338A DIGITAL DEMODULATOR 失效
公开(公告)号：JPH1155338A
公开(公告)日：1999-02-26
申请号：JP21183997
申请日：1997-08-06
申请人： NIPPON TELEGRAPH & TELEPHONE
发明人： KIZAWA TAKESHI , KOBAYASHI SEI , MORIKURA MASAHIRO
IPC分类号： H04L27/22
摘要： PROBLEM TO BE SOLVED: To sufficiently reduce a carrier wave frequency error, and to reduce an error rate in synchronization detection. SOLUTION: In this modulator, the orthogonal detection and phase conversion of a received DQPSK(differential quadrature phase shift keying) signal is operated, a phase at each symbol point is successively latched, carrier wave frequencies are corrected by a subtracting circuit 16, a phase error (a9) based on frequency deviation is detected from one symbol delay detection outputs of circuits 6 and 7 by a phase error detecting circuit 8, and an initial value a10 is obtained by an output circuit 9, and set in a circuit 13. Afterwards, a phase error a9 is inputted to a loop filter constituted of a gain circuit 11-adder circuit 12-initial value setting circuit 13-delay circuit 14-adder adder circuit 12, the filter output is integrated by a circuit 15, and supplied as frequency error components to the circuit 16. Then, a two symbol delay detection output is supplied to the phase error detecting circuit 8, and a three symbol delay detection output is supplied to the phase error detecting circuit 8 so that a carrier wave frequency error can be reduced.

40. 发明专利

JPH1141137A RECEIVING DEVICE FOR SPREAD SPECTRUM COMMUNICATION 失效
公开(公告)号：JPH1141137A
公开(公告)日：1999-02-12
申请号：JP19151197
申请日：1997-07-16
申请人： NIPPON TELEGRAPH & TELEPHONE
发明人： SUZUKI YASUO , KOBAYASHI SEI
IPC分类号： H04B1/707 , H04B1/712 , H04B7/08
摘要： PROBLEM TO BE SOLVED: To make it unnecessary to transmit a pilot symbol in addition to a start symbol for estimating propagation path characteristics, and to efficiently estimate the characteristics by operating envelope detection separately from the delay detection of an inverse spread signal, and estimating the propagation characteristics according to the detected result. SOLUTION: A start symbol spread spectrum by one spreading code is transmitted prior to signals (data symbol) transmitted in parallel. At the time of receiving the start symbol, orthogonal I signal and Q signal are inputted to passive correctors 10 and 11, and a correlation value is outputted from the passive correlator 10 matched with the spreading code of a transmission channel. The output signal of the passive correlator 10 is supplied to a delay detector 20, and also supplied to a delay detector 21 according to the switching of switches 1 and 2. The output signal of the passive corrector 10 is also inputted to an envelope detector 70, and envelop detection is operated. Then, an outputted envelope signal is supplied to a propagation path estimator 40, and used for estimating propagation characteristics.

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