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公开(公告)号：CA2043054C
公开(公告)日：1994-12-06
申请号：CA2043054
申请日：1991-05-22
Applicant: NEC CORP
Inventor： ICHIYOSHI OSAMU
Abstract: In a phase-lock loop device for phase locking a device input signal (11) representing a first complex number and having a device input phase which should be locked into a locked phase, a first complex multiplier (14) calculates a first product of the first complex number and a first conjugate complex number to produce a first complex product signal. The first conjugate complex number is represented by a first conjugate signal which is produced by delaying and processing the device input signal. A second complex multiplier (18) calculates a second product of a phase processed signal and a multiplier input signal to produce a second complex product signal. The phase processed signal is produced by filtering and processing the first complex product signal. The multiplier input signal is produced by delaying and limiting the second complex product signal. A third complex multiplier (22) calculates a third product of the first complex number and a second conjugate complex number to produce a third complex product signal. The second conjugate complex number is represented by a second conjugate signal which is produced by processing the second complex product signal. A fourth complex multiplier (24) calculates a fourth product of the second complex product signal and a filtered signal to produce a fourth complex product signal having the locked phase. The filtered signal is produced by filtering the third complex product signal.
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公开(公告)号：AU650170B2
公开(公告)日：1994-06-09
申请号：AU2609792
申请日：1992-09-30
Applicant: NEC CORP
Inventor： ICHIYOSHI OSAMU
IPC: H03H17/08 , H04L27/00 , H04L27/22 , H04L27/227 , H04L27/233 , H03L7/085 , H04L27/38
Abstract: In a phase divider, a complex signal containing a sequence of samples of real and imaginary values is limited to a unit amplitude and multiplied by a first complex multiplier with a first feedback complex signal, the output the multiplier being fed through a loop filter to a second complex multiplier where the signal is multiplied with a second feedback complex signal. The output of the second multiplier is limited to a unit amplitude, delayed by a sample interval and applied to the second complex multiplier as the second feedback complex signal. The first feedback complex signal is derived by a circuit that raises the frequency the delayed signal by a desired factor.
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公开(公告)号：CA2052589A1
公开(公告)日：1992-04-06
申请号：CA2052589
申请日：1991-10-04
Applicant: NEC CORP
Inventor： ICHIYOSHI OSAMU
Abstract: A first clock signal of f1 in frequency is converted into a second clock signal having a frequency of f2 = n/m f1. The first clock signal is converted by a tank circuit (12) and a converter (13) into an R-bit first phase signal ( theta 1) indicating the phase of the first clock signal. The first phase signal is multiplied by n (mod 2 ) by a multiplier into a second phase signal ( theta 3). The second phase signal is supplied to a digital phase-locked loop (PIL) (3) consisting of a subtractor (15), a low-pass filter (LPF) (16), a numerically controlled oscillator (NCO) (17) and a multiplier (18). The multiplier in the digital PIL (3) multiplies by m (mod 2 ) a third phase signal, indicating the phase of a second clock signal which is the output of the NCO (17), to generate a fourth phase signal. The subtractor (15) generates a signal representing the phase error between the second and fourth phase signals. This phase error signal is filtered by the LPF (16) to control the oscillating phase of the NCO (17). A clock generating circuit generates, on the basic of the third phase, signal, the second clock signal.
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公开(公告)号：CA1293999C
公开(公告)日：1992-01-07
申请号：CA575448
申请日：1988-08-23
Applicant: NEC CORP
Inventor： ICHIYOSHI OSAMU
Abstract: For use in a satellite communication system which carries out communication through a satellite by the use of an up-link frequency band and a down-link frequency band, each of the up-link and the down-link frequency bands has a plurality of frequency subbands spaced apart from one another with frequency gaps interposed between the frequency subbands. An earth station comprises a modulating arrangement (47) for modulating a selected one of the frequency subbands of the up-link frequency band by a first input signal into a subband transmission signal, a first transmitting arrangement (51) coupled to the modulating arrangement for transmitting the subband transmission signal through the selected one of the frequency subbands, a spread spectrum processing arrangement (50) for processing a second input signal into a spread spectrum transmission signal in the up-link frequency band, and a second transmitting arrangement (51) coupled to the spread spectrum processing arrangement for transmitting the spread spectrum transmission signal through the up-link frequency band.
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公开(公告)号：CA1291584C
公开(公告)日：1991-10-29
申请号：CA577002
申请日：1988-09-09
Applicant: NEC CORP
Inventor： ICHIYOSHI OSAMU
Abstract: A satellite communication system includes a plurality of mobile stations which are situated on the earth and a communication satellite which is communicable with the mobile stations by radio signals over a plurality of spot beams. The satellite applies single sideband amplitude modulation (SSB-AM) to analog signals which are sent from the mobile stations, applies digital modulation to coded voice and data, and separates signals in the form of frequency-division-multiplexed (FDM) signals on a channel basis by a transmultiplexer method which is implemented by demultiplexers of a transponder. Baseband matrix means is provided for connecting an output of any of the demultiplexers to one of the spot beams to be transmitted. Further, transmitting means is provided for time-division-multiplexing outputs of the baseband matrix means to form a transmit frame and transmitting it in the form of a TDM signal, On the other hand, each mobile station includes a receiver for selecting a channel signal to be received out of the TDM signal which is sent from the transmitting means of the onboard transponder, and demodulates it to regenerate a signal.
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Patent Agency Ranking
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公开(公告)号：AU599552B2
公开(公告)日：1990-07-19
申请号：AU2299988
申请日：1988-09-30
Applicant: NEC CORP
Inventor： ICHIYOSHI OSAMU
Abstract: A satellite-based vehicle communication/position determination system constituted by N (N >/= 3) geostationary satellites, a plurality of vehicle stations for performing radio-wave exchange with the satellites using a low-directivity antenna, and a base station having high-directivity antennas for independently performing radio-wave exchange with the N geostationary satellites is disclosed. The base station has a communication FDM receiver, N chirp signal receivers (4) for receiving and pulse compressing chirp signals from a vehicle station, which are obtained via the N geostationary satellites, and a circuit (5) for determining the position of the vehicle station based on time differences of compressed pulses from the chirp signal receivers. Each vehicle station has a communication FDM receiver, a transmitter, a chirp signal generator, and a switching control circuit for controlling to selectively output a transmitting signal or the chirp signal.
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公开(公告)号：CA1267703A
公开(公告)日：1990-04-10
申请号：CA506054
申请日：1986-04-08
Applicant: NEC CORP
Inventor： ICHIYOSHI OSAMU
Abstract: A modulator/demodulator operation mode control system specifies an operation mode, which is a combination of particular data transmission rate, multi-phase PSK modulation system, error-correction coding rate and others, in which a modulator/demodulator is to operate, while deciding the operation mode and controlling the modulator/demodulator. A transmit station designates a particular operation mode in a plurality of bits in terms of polarities of unique words, while a receive station switches a demodulator thereof to the designated operation mode responsive to an output of mode switchover signal decision means and based on signal representative of detection of the unique words.
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公开(公告)号：AU586858B2
公开(公告)日：1989-07-27
申请号：AU5569786
申请日：1986-04-07
Applicant: NEC CORP
Inventor： ICHIYOSHI OSAMU
Abstract: A modulator/demodulator operation mode control system (40) specifies an operation mode, which is a combination of particular data transmission rate, multi-phase PSK modulation system, error-correction coding rate and others, in which a modulator/demodulator is to operate, while deciding the operation mode and controlling the modulator demodulator. A transmit station designates a particular operation mode in a plurality of bits in terms of polarities of unique words, while a receive station switches a demodulator (42) thereof to the designated operation mode responsive to an output of mode switchover signal decision means (50) and based on signal representative of detection of the unique words.
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公开(公告)号：AU8305487A
公开(公告)日：1988-06-30
申请号：AU8305487
申请日：1987-12-24
Applicant: NEC CORP
Inventor： ICHIYOSHI OSAMU
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