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    Method and apparatus for improving AM compatible digital broadcast analog fidelity
    45.
    发明授权
    Method and apparatus for improving AM compatible digital broadcast analog fidelity 失效
    用于改善AM兼容数字广播模拟保真度的方法和装置

    公开(公告)号：US5859876A

    公开(公告)日：1999-01-12

    申请号：US671252

    申请日：1996-06-27

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

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

    IPC: H03C1/52 ,  H04H20/30 ,  H04H20/36 ,  H04L27/04 ,  H03C1/00 ,  H04L23/02 ,  H04N7/24

    CPC classification number: H03C1/52 ,  H04H20/36 ,  H04H20/30 ,  H04H2201/186

    Abstract: A digital signal transmission system is provided which minimizes the AM signal envelope distortion caused by multiple digitally modulated carriers in the same band as the AM signal. The system transmits an amplitude modulated signal. Digital carriers for the digital signal are placed both above and below the frequency of the analog AM carrier. Certain digital carriers that are above the frequency of the analog AM carrier have an associated digital carrier that is at an equal frequency offset below the analog AM carrier. The data and modulation placed on the upper digital carrier and its counterpart are such that the signal resulting from their addition has no component that is in-phase with the analog AM carrier. The signal envelope is predistorted to counteract the distortion added by the digital carriers.

    Abstract translation: 提供一种数字信号传输系统，其最小化由与AM信号相同的频带中的多个数字调制载波引起的AM信号包络失真。 系统发送振幅调制信号。 用于数字信号的数字载波被放置在模拟AM载波的频率之上和之下。 高于模拟AM载波频率的某些数字载波具有与模拟AM载波相同频率偏移的相关联的数字载波。 放置在上数字载波及其对应物上的数据和调制使得由它们的相加产生的信号没有与模拟AM载波同相的分量。 信号包络是预失真的，以抵消由数字载体添加的失真。

    Method and apparatus for improving the quality of AM compatible digital broadcast system signals in the presence of distortion
    46.
    发明授权
    Method and apparatus for improving the quality of AM compatible digital broadcast system signals in the presence of distortion 失效
    用于在存在失真的情况下提高AM兼容的数字广播系统信号的质量的方法和装置

    公开(公告)号：US5703954A

    公开(公告)日：1997-12-30

    申请号：US604199

    申请日：1996-02-20

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

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

    IPC: H04H20/26 ,  H04H20/33 ,  H04H40/18 ,  H04H5/00

    CPC classification number: H04H40/18 ,  H04H20/22 ,  H04H20/26 ,  H04H20/33 ,  H04H2201/186

    Abstract: A system and method are provided for reducing perceived distortion in an output audio signal derived from an amplitude modulated compatible digital broadcast signal having a monophonic portion and a stereo portion. The stereo portion of this signal is demodulated to produce a demodulated stereo signal and the monophonic portion of the signal is demodulated to produce a demodulated monophonic signal. The noise in the demodulated stereo signal is measured and an estimate of the signal-to-noise ratio is derived. This estimated signal-to-noise ratio is compared with a threshold level which is set at the minimum acceptable signal quality for the stereo signal. Based upon the estimated signal-to-noise ratio, a switch directs either the monophonic derived audio output or the stereo derived audio output as the system output signal.

    Abstract translation: 提供了一种系统和方法，用于减少从具有单声道部分和立体声部分的幅度调制兼容数字广播信号导出的输出音频信号中的感知失真。 该信号的立体声部分被解调以产生解调的立体声信号，并且信号的单声道部分被解调以产生解调的单声道信号。 测量解调立体声信号中的噪声，并推导出信噪比的估计。 将该估计的信噪比与对于立体声信号设置为最小可接受信号质量的阈值电平进行比较。 基于估计的信噪比，开关将单声道导出音频输出或立体声导出音频输出指导为系统输出信号。

    Adaptive mode control system for AM compatible digital broadcast
    47.
    发明授权
    Adaptive mode control system for AM compatible digital broadcast 失效
    用于AM兼容数字广播的自适应模式控制系统

    公开(公告)号：US5606576A

    公开(公告)日：1997-02-25

    申请号：US376987

    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: H04H60/11 ,  H04H60/13 ,  H04L5/02 ,  H03C5/00 ,  H04L25/03 ,  H04L25/06 ,  H04L27/06

    CPC classification number: H04H20/12 ,  H04H60/11 ,  H04H60/13 ,  H04L5/023

    Abstract: An adaptive mode control system is provided which includes a transmitter including apparatus for inputting format information regarding the waveform structure of an AM compatible digital broadcast signal. The transmitter also includes apparatus for inputting user data such as the information to be broadcast. The transmitter selects the waveform parameters in response to the format information and produces control channel information. The transmitter uses this control channel information in combination with the user data to produce composite data. The transmitter generates an over-the-air signal waveform using the composite data and waveform parameters. Each receiver includes apparatus for detecting the over-the-air signal waveform and composite data generated by the transmitter. The receiver further includes apparatus for parsing the composite data into user data and control channel information. The receiver regenerates the waveform parameters from the control channel information and folds the waveform parameters into the receiver's detection apparatus so that the waveform parameters can reconfigure the receiver for receipt of subsequent transmissions.

    Abstract translation: 提供一种自适应模式控制系统，其包括发射机，其包括用于输入关于AM兼容数字广播信号的波形结构的格式信息的装置。 发射机还包括用于输入诸如要广播的信息的用户数据的装置。 变送器根据格式信息选择波形参数，并产生控制信道信息。 发射机使用该控制信道信息与用户数据组合来产生复合数据。 发射机使用复合数据和波形参数生成空中信号波形。 每个接收机包括用于检测由空中信号波形和由发射机产生的复合数据的装置。 接收机还包括用于将复合数据解析为用户数据和控制信道信息的装置。 接收器从控制信道信息重新产生波形参数并将波形参数折叠到接收机的检测装置中，使得波形参数可以重新配置接收机以接收后续传输。

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