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    Apparatus and method for generating an AM-compatible digital broadcast waveform
    5.
    发明授权
    Apparatus and method for generating an AM-compatible digital broadcast waveform 失效
    用于产生AM兼容的数字广播波形的装置和方法

    公开(公告)号：US5930687A

    公开(公告)日：1999-07-27

    申请号：US724606

    申请日：1996-09-30

    Applicant: Mark J. Dapper ,  Michael J. Geile ,  Barry Walter Carlin

    Inventor： Mark J. Dapper ,  Michael J. Geile ,  Barry Walter Carlin

    IPC: H03C3/40 ,  H04H20/36 ,  H03C1/52

    CPC classification number: H03C3/40 ,  H04H20/36 ,  H04H2201/186

    Abstract: An apparatus and method for generating a broadcast waveform is provided which, for generating an in-phase component, includes an in-phase digital signal generator; a first filter for filtering the in-phase digital signal; a first digital-to-analog converter for converting the filtered digital signal into a first analog signal; an AM baseband signal generator producing an AM baseband signal; a first summer for summing the first analog and AM baseband signals to produce a composite analog signal; and a first modulator for modulating the composite analog signal with a first carrier signal at a transmission frequency, thus producing a first modulated signal. To provide the quadrature component of the broadcast waveform, the waveform generator includes a quadrature digital signal generator producing a quadrature digital signal; a second digital-to-analog converter for converting the quadrature digital signal into a second analog signal; a second modulator for modulating the second base-band signal with a second carrier signal; and a second summer for summing the first and second modulated signals, thus producing the broadcast waveform. The apparatus improves the signal-to-noise ratio in analog AM receivers, especially at higher frequencies.

    Abstract translation: 提供一种用于产生广播波形的装置和方法，用于产生同相分量包括同相数字信号发生器; 用于对同相数字信号进行滤波的第一滤波器; 第一数模转换器，用于将滤波后的数字信号转换成第一模拟信号; 产生AM基带信号的AM基带信号发生器; 第一个夏天用于求和第一个模拟和AM基带信号以产生复合模拟信号; 以及用于以传输频率用第一载波信号调制复合模拟信号的第一调制器，从而产生第一调制信号。 为了提供广播波形的正交分量，波形发生器包括产生正交数字信号的正交数字信号发生器; 用于将所述正交数字信号转换成第二模拟信号的第二数模转换器; 第二调制器，用第二载波信号调制第二基带信号; 以及第二加法器，用于对第一和第二调制信号进行求和，从而产生广播波形。 该装置提高了模拟AM接收机的信噪比，特别是在较高的频率下。

    Coherent signal detector for AM-compatible digital audio broadcast waveform recovery
    6.
    发明授权
    Coherent signal detector for AM-compatible digital audio broadcast waveform recovery 失效
    相干信号检测器用于AM兼容数字音频广播波形恢复

    公开(公告)号：US5878089A

    公开(公告)日：1999-03-02

    申请号：US803699

    申请日：1997-02-21

    Applicant: Mark J. Dapper ,  Barry W. Carlin ,  Michael J. Geile

    Inventor： Mark J. Dapper ,  Barry W. Carlin ,  Michael J. Geile

    IPC: H03D3/00 ,  H03D3/24 ,  H03G3/30 ,  H03D3/22

    CPC classification number: H03D3/244 ,  H03D3/009 ,  H03G3/3052

    Abstract: A coherent signal detector for extracting analog and digital information from a received AM-compatible digital broadcast waveform is provided. The waveform can have an in-phase component and a quadrature component. The detector can include a down converter for shifting the in-phase and quadrature components in phase, frequency, or both, in response to a phase word, thereby providing a recovered in-phase output and a recovered quadrature output. The signal detector also includes an integration circuit for integrating a portion of the recovered quadrature output over a first preselected time interval, which can be one digital time frame.

    Abstract translation: 提供了一种从接收的AM兼容数字广播波形中提取模拟和数字信息的相干信号检测器。 波形可以具有同相分量和正交分量。 检测器可以包括用于响应于相位字相位，频率或两者同步偏移同相和正交分量的下变频器，由此提供恢复的同相输出和恢复的正交输出。 信号检测器还包括积分电路，用于在第一预选时间间隔内对恢复的正交输出的一部分进行积分，其可以是一个数字时间帧。

    Equalization system for AM compatible digital receiver
    7.
    发明授权
    Equalization system for AM compatible digital receiver 失效
    AM兼容数字接收机的均衡系统

    公开(公告)号：US5559830A

    公开(公告)日：1996-09-24

    申请号：US376986

    申请日：1995-01-23

    Applicant: Mark J. Dapper ,  Michael J. Geile ,  Barry W. Carlin

    Inventor： Mark J. Dapper ,  Michael J. Geile ,  Barry W. Carlin

    IPC: H04H40/27 ,  H03H7/30

    CPC classification number: H04H40/27 ,  H04H2201/186

    Abstract: An equalizer is provided for enhancing the recoverability of digital audio broadcasting signal information. The equalizer receives the AM compatible digital audio broadcasting waveform and stores that waveform as a waveform vector. The equalizer then processes that waveform by multiplying the waveform vector by an equalization vector. This equalization vector comprises a plurality of equalizer coefficients, each of the coefficients initially set to a predetermined value. The equalizer then compares each location of the processed waveform vector with a stored waveform vector. The equalizer selects as the signal that vector location closest to the stored waveform vector. Preferably, the equalizer includes means for updating the equalizer coefficients using the waveform vector, the processed waveform vector, and the stored waveform vector to provide immunity to noise.

    Abstract translation: 提供均衡器以增强数字音频广播信号信息的可恢复性。 均衡器接收AM兼容数字音频广播波形并将该波形存储为波形向量。 然后，均衡器通过将波形矢量乘以均衡矢量来处理该波形。 该均衡矢量包括多个均衡器系数，每个系数初始设定为预定值。 然后，均衡器将经处理的波形向量的每个位置与存储的波形向量进行比较。 均衡器选择最接近存储的波形向量的向量位置的信号。 优选地，均衡器包括用于使用波形向量，经处理的波形向量和存储的波形向量来更新均衡器系数以提供对噪声的抗扰性的装置。

    Method of and apparatus for transmitting and recovering offset QPSK modulated data
    8.
    发明授权
    Method of and apparatus for transmitting and recovering offset QPSK modulated data 失效
    用于发送和恢复偏移QPSK调制数据的方法和装置

    公开(公告)号：US4281412A

    公开(公告)日：1981-07-28

    申请号：US54902

    申请日：1979-07-05

    Applicant: Frank A. Wissel ,  Donald E. Smith ,  Robert L. Martinet ,  Mark J. Dapper ,  Douglas A. Kiliman

    Inventor： Frank A. Wissel ,  Donald E. Smith ,  Robert L. Martinet ,  Mark J. Dapper ,  Douglas A. Kiliman

    IPC: H04L7/00 ,  H04L7/033 ,  H04L27/00 ,  H04L27/227 ,  H03D3/22 ,  H04L27/22

    CPC classification number: H04L27/2273 ,  H04L27/2082 ,  H04L7/0332 ,  H04L2027/0063 ,  H04L2027/0073 ,  H04L2027/0081 ,  H04L7/0004

    Abstract: Bit timing references are derived at a receiver for a carrier modulated by OQPSK. A carrier is transmitted with a constant reference phase modulation during a first interval. During a subsequent, second interval the carrier is transmitted with rotational phase modulation representing binary bit values so that orthogonal components phase modulate the carrier with a predetermined bit sequence. A receiver responds to the constant phase modulated carrier to lock the frequency and phase of a phase lock loop oscillator of a carrier recovery loop. Synchronization at the receiver is achieved in response to a reception of the rotational phase modulation, while maintaining the frequency and phase lock. A carrier recovery loop of the receiver is activated to a decision directed operation after bit synchronization has been achieved. Decision directed operation is achieved by sampling and comparing components derived in orthogonal channels of the carrier recovery loop while the receiver is responsive to the rotational phase modulation. The bandwidth of a filter used in achieving bit synchronization is reduced after there has been a decay of transients in the carrier tracking loop resulting from a transition between locking of the loop and initiation of the decision directed operation. Then the bandwidth of a filter in the carrier tracking loop is adjusted as a function of the quality of the received rotational modulated suppressed carrier.

    Abstract translation: 在由OQPSK调制的载波的接收机处导出比特定时参考。 在第一间隔期间以恒定的参考相位调制传输载波。 在随后的第二间隔期间，以表示二进制位值的旋转相位调制来传送载波，使得正交分量以预定位序列相位调制载波。 接收机响应恒定相位调制载波来锁定载波恢复环路的锁相环振荡器的频率和相位。 在保持频率和相位锁定的同时，响应于转动相位调制的接收来实现接收机的同步。 在实现位同步之后，接收器的载波恢复环路被激活以进行决策指示的操作。 通过对接收机响应于旋转相位调制的载波恢复环路的正交信道中导出的分量进行采样和比较来实现判决定向操作。 用于实现位同步的滤波器的带宽在载波跟踪环路中由于循环锁定和启动决策指令操作之间的过渡而导致的瞬态衰减被减小。 然后，根据接收到的旋转调制抑制载波的质量来调整载波跟踪环路中的滤波器的带宽。

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