公开(公告)号：WO1996023374A1

公开(公告)日：1996-08-01

申请号：PCT/US1995016027

申请日：1995-12-12

Applicant: NORTHROP GRUMMAN CORPORATION

Inventor： NORTHROP GRUMMAN CORPORATION ,  DAPPER, Mark, J. ,  GEILE, Michael, J. ,  CARLIN, Barry, W.

IPC: H04H01/00

CPC classification number: H04H40/27 ,  H04H2201/186

Abstract: An equalizer is provided for enhancing the recoverability of digital audio braodcasting 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编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。

公开(公告)号：WO1996021291A1

公开(公告)日：1996-07-11

申请号：PCT/US1995016024

申请日：1995-12-12

Applicant: NORTHROP GRUMMAN CORPORATION

Inventor： NORTHROP GRUMMAN CORPORATION ,  DAPPER, Mark, J. ,  GEILE, Michael, J. ,  CARLIN, Barry, W.

IPC: H04H01/00

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

Abstract: A digital signal transmission system is provided which minimizes the analog AM signal envelope distortion caused by multiple digitally modulated carriers in the same band as the analog AM signal. The present transmission system includes means for transmitting 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. Digital carrier pairs arranged in this way are said to be complementary. This configuration delivers dramatic fidelity improvements to analog AM reception of AM compatible digital braodcast signals. An additional means of reducing envelope distorsion is to predistort the signal envelope. 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，其最小化由与模拟AM信号相同的频带中的多个数字调制载波引起的模拟AM信号包络失真。 本传输系统包括用于发送幅度调制信号的装置。 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。 以这种方式布置的数字载体对被认为是互补的。 该配置为AM兼容数字编织信号的模拟AM接收提供了显着的保真度改进。 减少信封变形的另外一种手段是预测信号包络。 信号包络是预失真的，以抵消由数字载体添加的失真。