公开(公告)号：WO1997008866A1

公开(公告)日：1997-03-06

申请号：PCT/US1996013528

申请日：1996-08-21

Applicant: USA DIGITAL RADIO PARTNERS, L.P.

Inventor： USA DIGITAL RADIO PARTNERS, L.P. ,  CARLIN, Barry, W. ,  DAPPER, Mark, J. ,  GEILE, Michael, J.

IPC: H04L07/00

CPC classification number: H04H20/36 ,  H04H20/49 ,  H04H40/27 ,  H04H2201/186 ,  H04H2201/20 ,  H04L5/023 ,  H04L27/2602 ,  H04L27/2656 ,  H04L27/2662

Abstract: In a broadcast system having a complex waveform of digital and analog segments, frame timing is recovered (290) and the frame synchronous power (284) of the digital portion of the composite AM compatible Digital Audio Broadcast (DAB) waveform is measured by examining a portion of the signal (284). The frame timing necessary for proper demodulation is recovered from the received signal (200), and a signal power measurement for scaling (242) is provided (294). The composite AM compatible DAB waveform is produced by a modulation method in which a digital representation of an audio signal is encoded together with an analog amplitude modulated (AM) signal and transmitted simultaneously in the same frequency channel.

Abstract translation: 在具有数字和模拟段的复杂波形的广播系统中，恢复帧定时（290），并通过检查复合AM兼容数字音频广播（DAB）波形的数字部分的帧同步功率（284） 信号（284）的一部分。 从接收信号（200）恢复正确解调所需的帧定时，并提供用于缩放（242）的信号功率测量（294）。 复合AM兼容DAB波形通过调制方法产生，其中音频信号的数字表示与模拟幅度调制（AM）信号一起编码并在同一频道中同时传输。

公开(公告)号：WO1997008877A1

公开(公告)日：1997-03-06

申请号：PCT/US1996013526

申请日：1996-08-21

Applicant: USA DIGITAL RADIO PARTNERS, L.P.

Inventor： USA DIGITAL RADIO PARTNERS, L.P. ,  CARLIN, Barry, W. ,  DAPPER, Mark, J. ,  GEILE, Michael, J.

IPC: H04L27/06

CPC classification number: H03D1/2245 ,  H04H2201/186 ,  H04L27/265

Abstract: The invention provides a method and apparatus for demodulating a composite AM DAB waveform which contains digitally modulated carriers and which employ a mixer (180) for converting a received signal (170) into two signals, the first of these signals represents an in-phase component and the second of the signals represents a quadrature component, two analog-to-digital converters (182, 184) for converting the two signals into digital signals, and two fast Fourier transform elements (188, 190) for extracting data separately from the two digital signals. Complementary digital carrier signals are recovered from the quadrature, and non-complementary digital carriers are derived from a sum of the complementary data and the output of the in-phase component FFT process. Leakage of the AM signal through a highpass filter (186) is prevented from interfering with the demodulation of the complementary carrier signal's use of separated demodulation channels.

Abstract translation: 本发明提供了一种用于解调包含数字调制载波的复合AM DAB波形的方法和装置，其采用用于将接收信号（170）转换为两个信号的混频器（180），这些信号中的第一个表示同相分量 并且第二个信号表示正交分量，用于将两个信号转换成数字信号的两个模数转换器（182,184）和用于从两个信号分开提取数据的两个快速傅里叶变换元件（188,190） 数字信号。 从正交中恢复互补数字载波信号，并且从互补数据和同相分量FFT处理的输出之和导出非互补数字载波。 防止AM信号通过高通滤波器（186）的泄漏干扰互补载波信号对分离的解调信道的使用的解调。