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    • 3. 发明授权
    • OFDM modulator and OFDM modulation method for digital modulated wave having guard interval
    • 具有保护间隔的数字调制波的OFDM调制器和OFDM调制方法
    • US06304611B1
    • 2001-10-16
    • US09099390
    • 1998-06-18
    • Atsushi MiyashitaToshiyuki AkiyamaSeiichi SanoNobuo TsukamotoTatuhiro Nakada
    • Atsushi MiyashitaToshiyuki AkiyamaSeiichi SanoNobuo TsukamotoTatuhiro Nakada
    • H04K110
    • H04L27/2607H04L27/2626
    • An orthogonal frequency division multiplex (OFDM) modulator of such a system as to add guard intervals to a temporal waveform generated by modulating an input data train into a large number of (sub)carriers, conducting quadrature modulation, and outputting an OFDM signal. The OFDM modulator includes an IFFT circuit for conducting inverse fast Fourier transform processing to modulate the input data train into a large number of (sub)carriers, a guard interval adder for adding a guard interval to each effective symbol duration of a composite carrier signal supplied from the IFFT circuit and outputting a resultant signal, a control signal generator for generating, in synchronism with each guard interval of the composite carrier signal having the guard intervals added thereto, such a control signal as to attenuate signal amplitude of the composite carrier signal over an interval substantially equal in length to each guard interval; and an amplitude controller, responsive to the control signal, to attenuate the amplitude of the composite carrier signal supplied from the guard interval adder and output a resultant signal, only over an interval substantially equal in length to each guard interval. The amplitude controller outputting, in remaining intervals, the composite carrier signal supplied from the guard interval adder as it is.
    • 这种系统的正交频分复用(OFDM)调制器,用于通过将输入数据串调制成大量(子)载波,进行正交调制并输出OFDM信号而产生的时间波形增加保护间隔。 OFDM调制器包括用于进行快速傅立叶逆变换逆变换处理以将输入数据串调制成大量(子)载波的IFFT电路,用于将提供的复合载波信号的每个有效符号持续时间加上保护间隔的保护间隔加法器 从IFFT电路输出结果信号,控制信号发生器,与与其相加的保护间隔的复合载波信号的每个保护间隔同步地产生一个控制信号,以便衰减复合载波信号的信号幅度 长度与每个保护间隔基本相等的间隔; 以及振幅控制器,响应于控制信号,衰减从保护间隔加法器提供的复合载波信号的振幅,并输出结果信号,仅在长度上与每个保护间隔基本相等的间隔上。 幅度控制器以剩余的间隔输出从保护间隔加法器原样提供的复合载波信号。
    • 5. 发明授权
    • Method of an apparatus for demodulating amplitude-modulated signals in
an amplitude phase shift keying (APSK) system
    • 一种在幅度相移键控(APSK)系统中解调幅度调制信号的装置的方法
    • US6046629A
    • 2000-04-04
    • US96455
    • 1998-06-11
    • Toshiyuki AkiyamaAtsushi MiyashitaSeiichi SanoNobuo TsukamotoShigeki MoriyamaKenichi Tsuchida
    • Toshiyuki AkiyamaAtsushi MiyashitaSeiichi SanoNobuo TsukamotoShigeki MoriyamaKenichi Tsuchida
    • H04L27/38H03D3/00
    • H04L27/389
    • In a demodulating method of demodulating amplitude-demodulated signals in an amplitude phase shift keying system for conducting an amplitude modulation by setting signal points as information codes on a complex plane representing a signal space of transmission signals onto circumferences of two concentric circles including a first circle having a first diameter and a second circle having a second diameter smaller than the first diameter on the complex plane, there are obtained, in accordance with an amplitude value of an amplitude component of each symbol of a received amplitude-modulated signal, a first threshold value and a second threshold value having a predetermined relationship with the amplitude value. Next, the amplitude value the an amplitude component of each symbol of the successively received amplitude-modulated signal is compared with the first and second first threshold values to determine an amplitude variation in the amplitude component of each symbol in accordance with a result from the comparison so as to output therefrom a signal representing the determination result as a code obtained by demodulating the amplitude component.
    • 在解调幅度相移键控系统中的幅度解调信号的解调方法中,用于通过将表示发送信号的信号空间的信号空间的信号点设置为信号点进行幅度调制,以将发送信号的信号空间设置在包括第一圆周的两个同心圆的周围 具有第一直径和第二直径小于复平面上的第一直径的第二直径,根据接收到的幅度调制信号的每个符号的振幅分量的振幅值,获得第一阈值 值和与振幅值具有预定关系的第二阈值。 接下来,将连续接收的幅度调制信号的每个符号的振幅分量的振幅值与第一和第二第一阈值进行比较,以根据比较结果确定每个符号的幅度分量的振幅变化 从而从其输出表示确定结果的信号作为通过解调幅度分量而获得的代码。
    • 6. 发明授权
    • Data transmission apparatus and receiving apparatus using orthogonal frequency division multiplex modulation system
    • 数据传输装置和采用正交频分复用调制方式的接收装置
    • US06381251B1
    • 2002-04-30
    • US09096454
    • 1998-06-11
    • Seiichi SanoToshiyuki AkiyamaAtsushi MiyashitaNobuo Tsukamoto
    • Seiichi SanoToshiyuki AkiyamaAtsushi MiyashitaNobuo Tsukamoto
    • H04J100
    • H04L27/2662H04L27/2602H04L27/2675
    • A data transmission apparatus of an orthogonal frequency multiplex modulation system wherein data is transmitted using a plurality of carriers which are in a mutually orthogonal relationship with one another. The apparatus includes a transmitter which previously inserts a group of predetermined synchronization symbols into an OFDM modulated transmission signal every fixed period and a receiver which demodulates a received OFDM modulated transmission signal to a baseband OFDM signal. In the receiver, an absolute value of an A/D converted digital signal is taken and the signal is bandwidth-limited to a predetermined band width. Then, it is decided whether an amplitude of the signal is larger than or smaller than a predetermined value and a decision result thereof is produced. A null section in the synchronization symbol group is detected on the basis of the decision result and a start point of another synchronization symbol subsequent to the null section is further detected. The time when both of the presence of the null section and the start point of another synchronization symbol are detected is regarded as a synchronization timing and the operation timing of a demodulator for the receiver is set to the synchronization timing.
    • 正交频分复用调制系统的数据发送装置,其中使用彼此相互正交的多个载波来发送数据。 该装置包括一个发送器,其先前将一组预定的同步符号插入每个固定周期的OFDM调制的传输信号,以及一个接收机,将接收的OFDM调制的传输信号解调为基带OFDM信号。 在接收机中,采用A / D转换的数字信号的绝对值,并将信号带宽限制在预定的带宽。 然后,确定信号的幅度是否大于或小于预定值,并且产生其判定结果。 基于判定结果来检测同步符号组中的零部分,并进一步检测到零部分之后的另一个同步符号的起始点。 检测到零段的存在和另一个同步符号的起始点的时间被认为是同步定时,并且用于接收机的解调器的操作定时被设置为同步定时。
    • 8. 发明授权
    • Bi-directional digital transmission system and bi-directional digital transmission method
    • 双向数字传输系统和双向数字传输方式
    • US06381236B1
    • 2002-04-30
    • US09236602
    • 1999-01-26
    • Atsushi MiyashitaToshiyuki AkiyamaNobuo Tsukamoto
    • Atsushi MiyashitaToshiyuki AkiyamaNobuo Tsukamoto
    • H04J100
    • H04L5/1484H04L5/023
    • A bi-directional digital transmission method, and system, for sending and receiving digital transmission signals having a frame configuration modulated by an orthogonal frequency division multiplex modulation scheme. A first sending unit in a first transmission station converts first continuous data to a up-direction intermittent transmission signal, and sends it from a first antenna via a first switchover unit. The up-direction intermittent transmission signal is received by a second antenna of a second transmission station, and supplied to a second receiving unit of the second transmission station via a second switchover unit of the second transmission station. The second receiving unit determines whether receiving operation of the up-direction intermittent transmission signal has been established, and if so, restores the original first continuous data. A second sending unit in the second transmission station converts second continuous data to a down-direction intermittent transmission signal, and sends it from a second antenna via a second switchover unit. In the first transmission station, the down-direction intermittent sending transmission signal is received by the first antenna, and supplied to a first receiving unit via the first switchover unit to restore the original second continuous data.
    • 一种用于发送和接收具有由正交频分复用调制方案调制的帧配置的数字传输信号的双向数字传输方法和系统。 第一发送站中的第一发送单元将第一连续数据转换为上行间歇发送信号,并经由第一切换单元从第一天线发送。 上行间歇发送信号由第二发送站的第二天线接收,经由第二发送站的第二切换单元提供给第二发送站的第二接收单元。 第二接收单元确定上行间歇发送信号的接收操作是否已经建立,如果是,则恢复原始的第一连续数据。 第二发送站中的第二发送单元将第二连续数据转换为下行间歇发送信号,经由第二切换单元从第二天线发送。 在第一发送站中,向下方向间歇发送发送信号由第一天线接收,经由第一切换单元提供给第一接收单元,恢复原来的第二连续数据。
    • 9. 发明授权
    • Digital communication system of orthogonal modulation type
    • 正交调制型数字通信系统
    • US06512798B1
    • 2003-01-28
    • US09262840
    • 1999-03-05
    • Toshiyuki AkiyamaAtsushi MiyashitaNobuo Tsukamoto
    • Toshiyuki AkiyamaAtsushi MiyashitaNobuo Tsukamoto
    • H04L512
    • H04L27/2071H04L25/03834
    • A digital signal communication system includes a transmission circuit or a receiving circuit for digitally transmitting two types of signals by orthogonal modulation. The transmission circuit includes an orthogonal modulator and a nonrecursive digital low-pass filter having the same frequency characteristic as a predetermined frequency characteristic of the output signal of the orthogonal modulator. The receiving circuit includes an orthogonal demodulator and a nonrecursive digital low-pass filter having the same frequency characteristic as a predetermined frequency characteristic of the output signal of the orthogonal demodulator. The total number of taps required for determining the frequency characteristic of the nonrecursive digital low-pass filter is set to H, and the series of tap coefficients is set as C1, C2, C3, . . . , CH, where H is an arbitrary positive integer of not less than 2. The nonrecursive digital low-pass filters include a first low-pass filter for filtering one of the two types of signal and a second low-pass filter for filtering the other type of the signal. The first low-pass filter has taps about one half of H including a tap coefficient series C1, C3, C5, . . . , CODD, and the second low-pass filter has taps about one half of H including a tap coefficient series C2, C4, C6, . . . , CEVEN.
    • 数字信号通信系统包括用于通过正交调制数字地发送两种类型的信号的发送电路或接收电路。 发送电路包括具有与正交调制器的输出信号的预定频率特性相同的频率特性的正交调制器和非递归数字低通滤波器。 接收电路包括具有与正交解调器的输出信号的预定频率特性相同的频率特性的正交解调器和非递归数字低通滤波器。 用于确定非递归数字低通滤波器的频率特性所需的抽头总数设置为H,并且抽头系数串被设置为C1,C2,C3。 。 。 ,CH,其中H是不小于2的任意正整数。非递归数字低通滤波器包括用于对两种类型的信号中的一种进行滤波的第一低通滤波器和用于滤除另一种信号的第二低通滤波器 信号类型。 第一个低通滤波器具有大约H的一半的抽头,包括抽头系数C1,C3,C5。 。 。 ,CODD,第二低通滤波器具有大约H的一半的抽头,包括抽头系数C2,C4,C6。 。 。 ,CEVEN。