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公开(公告)号：JPH07231311A
公开(公告)日：1995-08-29
申请号：JP4200494
申请日：1994-02-16
Applicant: NEC CORP
Inventor： NISHIYAMA TAKEHIRO , ICHIYOSHI OSAMU
Abstract: PURPOSE:To reduce the cost of the broadcast system and to facilitate the installation the broadcast system. CONSTITUTION:A broadcast base station 1 is constituted by connecting a broadcast instrument 2 and a personal radio equipment 3 provided with a omnidirectional antenna, and the antenna is installed at a high place as much as possible so that an unobstracted view can be obtained. Broadcast repeater stations 4-1-4-4 are constituted by connecting personal radio equipment 5-1-5-4 respective provided with directivity antennas and medium/short wave radio equipment 6-1-6-4 provided with omnidirectional antennas. The broadcasts transmitted from the omnidirectional antennas of the medium/short wave radio equipment 6-1-6-4 are respectively received by receivers 11-18.
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公开(公告)号：JPH0738522A
公开(公告)日：1995-02-07
申请号：JP20289293
申请日：1993-07-23
Applicant: NEC CORP
Inventor： ICHIYOSHI OSAMU
Abstract: PURPOSE:To provide a multiplexing conversion system, for which it is not necessary to synchronize the timing of a modulated signal with a charp signal, concerning the multiplexing conversion system to convert a frequency-divided multiplex signal into a time-divided multiplex signal. CONSTITUTION:A charp signal generator 41 generates the charp signal for performing frequency sweeping in cycle shorter than the modulation speed of each channel of the frequency-divided multiplex signal to be converted more than two times at least at the degree of the band width of the entire frequency- divided multiplex signal. A multiplier 6 performs frequency sweeping while inputting the charp signal and the frequency-divided multiplex signal. A convolver 9 performs pulse compression to the output signal of the multiplier 6. Mixers 11 and 12 respectively separately perform frequency conversion to the output signal of the convolver with the charp signals which passes are different each other for pi/2. A FIR filter 42 outputs the signals of respective channels in the manner of time division by performing prescribed weighting to the signal inputted through an A/D converter 13.
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公开(公告)号：JPH06334603A
公开(公告)日：1994-12-02
申请号：JP12014993
申请日：1993-05-21
Applicant: NEC CORP
Inventor： ICHIYOSHI OSAMU
Abstract: PURPOSE:To improve a power efficiency by using a TDMA system in a line from a base station to a compact station, and using a burst-shaped frequency division multiple system and single carrier signal system in the line from the compact station to the base station. CONSTITUTION:At the time of communication, a control part 9 controls a switching part 14 by a transmitting/receiving operation switching signal, and controls the switcher 14 only in a period when a TDMA signal from the base station to its own station destination is present in order to connect an antenna 3 with a receiving part. Otherwise, the control part 9 controls the switcher 14 in order to connect a transmitting part with the antenna 3. A transmission base band processing circuit 10 divides transmitted data into transmission frames by a transmission frame timing supplied from the control part 9, operates the speed conversion of the data, and constitutes a burst signal in each frame. Moreover, the transmission base band processing circuit 10 adds a preamble signal to the head of each burst, and operates time adjustment so that a transmission burst signal can be supplied through the switcher 14 to the antenna 3 synchronously with a switching signal.
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公开(公告)号：JPH06104947A
公开(公告)日：1994-04-15
申请号：JP25152992
申请日：1992-09-21
Applicant: NEC CORP
Inventor： ICHIYOSHI OSAMU
IPC: H04L27/22
Abstract: PURPOSE:To miniaturize equipment by multiplying a local oscillation signal whose frequency is equal to a carrier frequency with a reception signal so as to apply frequency conversion to the product at a base band thereby eliminating the need for a frequency conversion circuit. CONSTITUTION:A reception radio signal subject to quadrature phase modulation via a low noise amplifier 6 is divided into two and they are respectively fed to mixers 8, 9. The mixers 8, 9 receive a local oscillation signal whose frequency is equal to a carrier frequency outputted by a reception synthesizer 11 and a similar local oscillation signal via a pi/2 phase sifter 10 and both the applied signals are multiplied in the mixers and direct frequency conversion to a base band is attained. Then the converted signals are respectively processed by DC amplifiers 12, 13 built in LPP 120, 130 or the like. Thus, no frequency conversion circuit is required and the small sized communication equipment whose configuration is simplified is obtained.
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公开(公告)号：JPH0661851A
公开(公告)日：1994-03-04
申请号：JP20865192
申请日：1992-08-05
Applicant: NEC CORP
Inventor： ICHIYOSHI OSAMU
Abstract: PURPOSE:To generate a frequency signal controlled by a numeral given externally by controlling a phase of a voltage controlled oscillator with an output of a loop filter. CONSTITUTION:An output of binary integration circuits 7, 13 are phase information expressed in the accuracy of R-bits, and a phase difference is detected by calculating a difference of both the outputs at an R-bit binary adder 10. The difference is converted into an analog value at a D/A converter 11 of a next stage and then the succeeding processing is the same as a conventional phase locked loop. A delay in the PLL is produced only in a frequency divider 12 and then the delay in the loop is less by selecting the operating speed of the frequency divider 12 the same as that of a reference oscillator 1. Thus, a sufficient broad band operation is provided to the PLL and an output of internal noise of the VCO 1 is suppressed. Furthermore, a quantization error by digital processing is suppressed by selecting an input bit number R of the D/A converter 11 larger.
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Patent Agency Ranking
公开(公告)号：JPH05308311A
公开(公告)日：1993-11-19
申请号：JP11146692
申请日：1992-04-30
Applicant: NEC CORP
Inventor： ICHIYOSHI OSAMU
Abstract: PURPOSE:To connect a moving body and a ground station, and moving bodies mutually by inputting the demultiplexed signal from a moving body to a base band processing circuit and making a switching connection with a specific moving body under connection switching control from the ground station, and then transmitting the signal. CONSTITUTION:The base band processing circuit 9 connects a group of input signals of demultiplexing circuits 6 and 7 to the output signals of multiplexing circuits 5 and 8 under the control of a control circuit 10. Consequently, even when the circuit 6 is connected to the circuit 6, namely, when the moving body 16 is connected to another moving body 16, it is connected even to a circuit 8 and the signals are transmitted to the ground station 15 without fail even in a communication between the moving bodies 16. Therefore, the ground station 15 can grasp the communication state of even the mutual communication between the moving bodies 16. The most economical communication can be set on demand at all times for the communication between the moving bodies 16, and the moving body 16 and ground station 15.
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公开(公告)号：JPH0583313A
公开(公告)日：1993-04-02
申请号：JP23996891
申请日：1991-09-19
Applicant: NEC CORP
Inventor： ICHIYOSHI OSAMU
IPC: H04L27/227 , H04L27/00 , H04L27/22 , H04L27/233
Abstract: PURPOSE:To obtain the demodulation circuit required for burst operation under a low C/N condition. CONSTITUTION:A reception signal is subjected to quasi-synchronization detection, the result is A/D-converted and automatic frequency control(AFC) is applied by a numerical controlled oscillator 10, the result is inputted to channel filters 8-1,8-2, their outputs are multiplied by (m) and inputted to plural tank circuits 16-1-16-N each comprising a tank tuned to an integral number of multiple of a frequency interval DELTAf and an input output correlation device. A tank circuit having a maximum correlation is selected among them and carrier recovery/ synchronization detection is implemented based on the output and the numerical controlled oscillator is controlled to be featured for AFC based on a frequency error signal obtained by the sum of an imaginary part output of a correlation function and a quantity proportional to the tuning frequency of the selected filter circuit. Thus, the burst operation is attained under a condition of a low C/N and a wide synchronization frequency range and broad application to the mobile body communication is attained.
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公开(公告)号：JPH04271519A
公开(公告)日：1992-09-28
申请号：JP3254891
申请日：1991-02-27
Applicant: NEC CORP
Inventor： ICHIYOSHI OSAMU
Abstract: PURPOSE:To realize a frequency synthesizer in which a frequency range is large with a small frequency step and phase noise is less. CONSTITUTION:The output of a reference oscillator 1 is counted by a frequency divider 2 to output a modulo M count (m), then a step frequency is generated through 1/M frequency division. A phase conversion circuit 7 applies the arithmetic operation of K(m/M) to the counted value (m) to generate a reference phase signal. The output of a VCO 5 generating a signal at a required frequency being a multiple of a value N with the step frequency is counted by a programmable frequency divider 6, which outputs a modulo N counted value (n) to implement 1/N frequency division. A phase conversion circuit 9 applies the arithmetic operation of K(m/N) to the count value (n) to generate an output phase signal. An adder 7 generates a modulo K difference between the reference phase signal and the output phase signal. The output of an adder 8 is converted into an analog signal by a D/A converter 10, the signal is smoothed by a loop filter 4 and the result is used for a phase control signal of the VCO 5.
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公开(公告)号：JPH04185016A
公开(公告)日：1992-07-01
申请号：JP31287490
申请日：1990-11-20
Applicant: NEC CORP
Inventor： ICHIYOSHI OSAMU
IPC: H03L7/197
Abstract: PURPOSE:To generate a frequency synthesized signal of less phase noise in a narrow frequency step by supplying the output of a loop filter to a VCO. CONSTITUTION:A counter 21 divides the frequency of a reference frequency signal by M and sends a counted value (m) to a phase converter 22, and the counted value (m) is converted to a phase thetaR and is sent to a 1st cosine/sine complex signal making circuit 71 and is converted to a complex signal. A programmable counter 61 divides the frequency of the output of a VCO 5 by N in accordance with the variable frequency division ratio N, and a counted value (n) is converted to a phase value theta0 by a phase converter 62 and is sent to a 2nd cosine/sine complex signal making circuit 72 and is converted to a complex signal. Respective complex signals are multiplied by a complex multiplier 31, and only the imaginary part of the multiplication result is sent to an LPF 4. The phase difference is correctly detected at the time of phase- locking. The equivalent band width of a phase locked loop is not limited and can be set to an arbitrary value.
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公开(公告)号：JPH03272246A
公开(公告)日：1991-12-03
申请号：JP7246690
申请日：1990-03-20
Applicant: NEC CORP , NIPPON ELECTRIC ENG
Inventor： ICHIYOSHI OSAMU , TANAKA SHINICHI
IPC: H04L27/227 , H04L27/22
Abstract: PURPOSE:To improve the bit error rate characteristic by providing a 2nd complex number multiplier receiving an output signal from a delay device and a 1st complex number multiplier and applying complex number multiplication, a carrier frequency error discriminator and an AFC circuit and detecting an output of a 1st complex number multiplier. CONSTITUTION:An AFC circuit consists of a numeral control oscillator NCO 7, a 1st complex number multiplier 1, a delay device 4, a 2nd complex number multiplier 2, a carrier frequency error discriminator 5 and an LPF 6 so as to make a carrier frequency error of a signal SH zero. A carrier recovery circuit 10 receives the signal SH without a carrier frequency error to generate a recovered carrier and outputs it to a 3rd complex number multiplier 3. The complex number multiplier 3 uses the recovery carrier to apply synchronization detection to the signal SH without a carrier frequency error and outputs a demodulation data signal So.
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