CN1143463C - 调幅和数字共存的广播方法及装置 - Google Patents
调幅和数字共存的广播方法及装置 Download PDFInfo
- Publication number
- CN1143463C CN1143463C CNB951919989A CN95191998A CN1143463C CN 1143463 C CN1143463 C CN 1143463C CN B951919989 A CNB951919989 A CN B951919989A CN 95191998 A CN95191998 A CN 95191998A CN 1143463 C CN1143463 C CN 1143463C
- Authority
- CN
- China
- Prior art keywords
- signal
- frequency
- carrier signal
- digitally modulated
- radio
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Images
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q1/00—Details of selecting apparatus or arrangements
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04H—BROADCAST COMMUNICATION
- H04H20/00—Arrangements for broadcast or for distribution combined with broadcast
- H04H20/28—Arrangements for simultaneous broadcast of plural pieces of information
- H04H20/36—Arrangements for simultaneous broadcast of plural pieces of information for AM broadcasts
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/02—Transmitters
- H04B1/04—Circuits
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/26—Systems using multi-frequency codes
- H04L27/2601—Multicarrier modulation systems
- H04L27/2602—Signal structure
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L5/00—Arrangements affording multiple use of the transmission path
- H04L5/02—Channels characterised by the type of signal
- H04L5/023—Multiplexing of multicarrier modulation signals
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04H—BROADCAST COMMUNICATION
- H04H2201/00—Aspects of broadcast communication
- H04H2201/10—Aspects of broadcast communication characterised by the type of broadcast system
- H04H2201/18—Aspects of broadcast communication characterised by the type of broadcast system in band on channel [IBOC]
- H04H2201/186—AM digital or hybrid
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/26—Systems using multi-frequency codes
- H04L27/2601—Multicarrier modulation systems
- H04L27/2602—Signal structure
- H04L27/26035—Maintenance of orthogonality, e.g. for signals exchanged between cells or users, or by using covering codes or sequences
Landscapes
- Engineering & Computer Science (AREA)
- Signal Processing (AREA)
- Computer Networks & Wireless Communication (AREA)
- Digital Transmission Methods That Use Modulated Carrier Waves (AREA)
- Transmitters (AREA)
- Circuits Of Receivers In General (AREA)
- Two-Way Televisions, Distribution Of Moving Picture Or The Like (AREA)
- Amplitude Modulation (AREA)
- Alarm Systems (AREA)
Abstract
在标准AM广播信道上同时发射模拟和数字信号的方法,发射一个具有第一频谱的包括一个由模拟信号调制的第一载波的调幅射频信号;同时发射一组数字载波信号,这些信号位于包括所述第一频谱的频段内。每个数字调制载波均被数字信号的一部分所调制。其中第一组数字调制载波信号位于第一频谱范围内,并与第一载波信号相正交。第二和第三组数字调制载波信号位于第一频谱之外,并均与第一载波信号同相和正交。
Description
技术领域
本发明涉及无线广播,尤其涉及用于在同一所分配频道内发送数字调制信号和模拟调幅信号的方法和装置。
背景技术
能否通过发送数字编码的声频信号来提高声频保真度,已受到越来越多人的关注。已提出的一些建议包括:带外技术,该技术用专门指定的频段来发送数字广播信号;带内技术,该技术实现了在商用广播目前所使用的同一频道内或在现在频段的相邻频道的空闲时间段内,对射频信号的发送(在不同频道方式下采用的方案分别为同频道带内方案和填隙方案)。在这两种方案中,带内方案不需要额外的频率调整并只需相对较少地改变现有传输设备。当然,任何数字声频广播(DAB)技术都应该保证不损害传统的模拟接收电路的接收质量。
因为AM(调幅)信道的带宽很窄,所以数字声频广播的带内实施方案到目前为止,只能在FM波段(88MHz-108MHz)中使用。然而,在AM波段内(530KHz-1700KHz)使用数字声频广播将提高AM广播电台的竞争力,使它们可以与盒式磁带、压缩光盘等高质便携的声频设备相抗衡。因此,人们就希望把同频道带内方案应用到AM广播频率中,以通过数字信号来提高保真度,而又不损害现有AM接收机的接收质量。
发明内容
本发明的广播方法使用了一组复合波,它包括:一个调幅射频信号,在该调幅射频信号中包含一个经模拟广播信号调幅的第一载波;以及多个数字调制载波信号,这些信号存在于包括调幅射频信号频谱的频段之内,每个数字载波信号均由数字信号的一部分数字调制所得,其中,第一组数字调制载波信号覆盖了调幅射频信号的频谱,并被调制成与第一载波信号相正交,第二和第三组数字调制载波信号的频率在调幅射频信号的频谱之外,并均与第一载波信号同相和正交。
本发明还包括一个射频发射机,它包括:发射复合射频信号的装置,该复合射频信号中包括一个调幅射频信号,在该调幅射频信号中包含经模拟信号调幅的第一载波,以及多个数字调制载波信号,这些信号存在于包括调幅射频信号频谱的频段内。每个数字载波信号均经由数字信号的一部分数字调制所得,其中,第一组数字调制载波信号覆盖了调幅射频信号的频谱,并被调制成与第一载波信号相正交,第二和第三组数字调制载波信号的频率在调幅射频信号的频谱之外,并均与第一载波信号同相和正交。
发射根据本发明的信号的发射机,采用了一种调制电信号的方法,该方法包括以下步骤:在第一频段内提供一个调幅信号;在第一频段内提供第一组正交调幅载波;在第二、第三频段内提供第二和第三组正交调幅载波,第二和第三频段分别包括高于和低于第一频段频率的频率。
本发明还包括一个射频接收机,它包括:接收复合射频波中模拟和数字部分的装置;在该复合射频波中包括第一信号,在该信号中包含经模拟信号调幅的第一载波,以及多个数字调制载波信号,这些信号存在于包括调幅射频信号频谱的频段内,每种数字载波信号均经数字信号的一部分数字调制所得,其中,第一组数字调制载波信号覆盖了调幅射频信号的频谱,并被调制成与第一载波信号相正交,第二和第三组数字调制载波信号的频率在调幅射频信号的频谱之外,并均与第一载波信号同相和正交;检测第一载波上模拟信号的装置;检测数字调制载波上数字信号的装置。
本发明提供了一种同频道带内发射方法,通过该方法可以在现有的AM广播频道内发射声音节目的数字编码和其它数字数据,而不会对AM模拟接收机造成不利影响,并且只需相对少量地对目前的AM传输设备进行变动,本发明包含与这种发射方法相适应的发射机和接收机。
附图说明
通过参照附图,本领域的技术人员将能更清楚地理解本发明,图示包括:
图1是一个具有根据本发明定位的载波的模拟AM信号和数字广播信号的复合信号的频谱图示;
图2是根据本发明制造的发射机结构的框图;
图3是图2所示发射机所用的数据分析器框图;
图4是根据本发明的接收机结构的框图。
具体实施方式
本发明提供了一种在目前模拟AM广播所使用的频道上同时发送一个模拟调幅信号和数字信号的方法。当这一技术应用于AM无线广播时,这种无线广播可以在其目前所分配的频段上,并在同一载波频率上得以实现。在发送模拟AM信号的信道内同时发送数字信号的技术称为同频道带内技术(IBOC)。为了满足避免相互干扰的需要,必须对位于模拟AM频谱下方的数字波进行限制。本文所述的广播方法通过采用多个载波来传送数字波的方式来得以实现,一些载波被调制成与模拟AM信号相正交,并位于标准AM广播信号能量集中所在的同一频谱区域内,其余的数字载波被调制成与模拟AM信号同相和正交,并与模拟AM信号位于同一信道,但却分布在模拟AM信号能量较弱的频谱区域。有许多种方法可以产生正交信号,本发明不包含产生正交信号的具体方法。在美国,AM广播电台的信号发送要符合联邦通信委员会(FCC)的一些规定,以下即为FCC所定义的信号电平屏蔽(level mask)规定:从模拟载波上所辐射的10.2KHz~20KHz的信号,必须被衰减到低于未调制模拟载波电平至少25分贝,从模拟载波上辐射的20KHz~30KHz的信号,必须被衰减到低于未调制模制载波电平至少35分贝,从载波上所分离的30KHz~60KHz的信号,必须被衰减到低于未制减模拟载波电平至少(5+1dB/KHz)。
图1展示了一个具有根据本发明定位的载波的AM数字声频广播信号的频谱。曲线10代表了标准广播调幅载波信号,其中载波的频率为f0。FCC的发射屏蔽规定如标号12所示。信源编码的一些新进展,例如德国Institut Fur Rund funkfechnik MUSICAM(适于屏蔽图形的子带编码和复用)算法表明,在9.6千比特每秒(kbps)的低速率下发送数字信号,可以提高立体声广播的声音质量。支持这一速率的波形可以通过应用带宽有效调制技术,***到目前分配给AM电台的FCC辐射屏蔽中。
本发明中的数字调制载波由正交频率分割复用(OFDM)产生。这种方式使这些载波的频谱可以相互重叠而不需要任何干扰防护频带,进而优化频谱的应用。然而,可以在时域内采用防护间隔以补偿信号定时的抖动。OFDM调制技术对于成功地实现DAB尤其有益,因为在AM频段中带宽是一种极宝贵的资源。除此之外,OFDM的另一好处是不需要对发射机或接收机中的载波信号进行滤波隔离,因为OFDM的正交特性使它们之间的干扰达到了最小。
OFDM波由一系列间隔为500Hz的数据载波组成。这样既增强了频谱容量,并保证AM DAB波在遵守FCC辐射屏蔽规定的前提下,尽可能地接近屏蔽极限。将方案的另一特性是可以在可能产生强干扰的地区,例如,靠近干扰信号载波频率的地区,特定地提高信号功率,这种策略保证信号能量可以尽可能合理地分配并借此扩大AM DAB的覆盖区域。
在本发明中,模拟和数字DAB的复合波包括多个完全符合FCC辐射屏蔽的调制载波。在本发明的选实施例方案中,使用了间隔为500Hz的76个载波来携带数字信息。第一组的34个数字调制载波位于f0-17f1到f0+17f1的频率范围内,如图1中框14所示。大部分信号比未调制的AM载波信号低30~40分贝,以减少与模拟AM信号的串音。通过对数字信息与模拟AM波正交的方式进行编码,可以进一步降低串者。这种编码方式叫做互补编码(例如互补BPSK,互补QPSK,或互补32QAM)。位于最内侧的f0±f1频率处的数字载波采用互补BPSK方式调制,以利于通过科斯环进行定时恢复。这些载波的电平被设置在一25dBc。第一组中位于f0-10f1~f0-2f1,和f0+2f1~f0+10f1频段间的18个载波用互补QPSK调制,其电平为-39.7dBc,第一组载波中的最后14个位于f0-17f1~f0-11f1和f0+11f1~f0+17f1,这些载波使用互补32QAM调制,其电平为-30dBc。
其它组正交调幅数字信号位于第一组的频段之外。通过对模拟AM信号带宽的限制,消除了对数字波形必须与模拟信号相正交的要求。因为模拟AM接收机中广泛使用的陶瓷IF滤波器通常将声频响应限制在3.5KHz之内,所以上述对模拟信号带宽的限制并不是非份的要求。第二组中的全部载波,如图1中框16、18所示,均使用32QAM调制,位于f0-19f1,f0-18f1,f0+18f1和f0+19f1频段的载波电平为-28dBc,位于f0-39f1~f0-34f1,f0-21f1,f0+21f1,f0+34f1~f0+39f1频段处的载波电平为-31dBc。其余位于f0-33f1~f0-22f1和f0+22f1~f0+33f1处的载波电平为-32dBc。
OFDM载波之间间隔f1=500Hz,但是,因为使用了时域防护带,每个载波的码率fr=128·500/132码元每秒。采用互补BPSK编码调制的一对载波的每个码元由一比特构成,所以其比特率即为fr。9对采用互补QPSK编码调制的载波中,每码元由2比特构成,其比特率为18fr。7对采用32QAM进行调制的载波,每码元由5比特组成,比特率为35fr。42个单独的32QAM调制载波,每码元由5比特构成,其比特率为210fr。OFDM载波总速率为264fr或128K比特每秒。
整个复合AM DAB信号的占用带宽,到数字波形最外端的第一个空位为止,共为40KHz。这种频谱落到了FCC辐射屏蔽中心40KHz部分之内,因为OFDM旁瓣间隔只有f1=500Hz,所以扩散到f0±20KHz频率之外的OFDM旁瓣,无需任何额外的滤波,即可落到辐射屏蔽低于-35dBc的部分。
在±20f1和±40f1处有空闲的OFDM时隙。因为主要的AM信号分量出现在载波频率处,所以这进一步阻止了第一和第二相邻频道的干扰。同样地,AM DAB增谱实际在f0±20KHz以外的部分实际上也并未被占用,从而在一定程度了提供了对第二相邻信道干扰的保护。
图2是根据本发明制造的发射机结构的框图。一个将被发送的模拟节目信号(在本例中包括右侧和左侧立体声部分)被施加到输入端28和28’,左右信道在加法器29处合并,然后通过一个模频处理器,将模拟AM信号的调制由30%提高到85%,这就相当大地扩展了信号覆盖区域。这种处理器在世界各地的摸拟AM广播电台中都很常见。信号接着通过一个具有尖锐截止特性的低通滤波器,在线32上产生一个经过滤的单声道模拟信号。比如说,滤波器31可以具有6KHz的截止频率并对6.5KHz以上部分进行40dB衰减。
在同时利用发送信号的模拟部分和数字部分来传送同一节目时,数字源编码器34,它可能遵从ISO MPEG2A层协议,将右侧和左侧模拟信号转变为一个96kbps的接合立体声数字信号,在线36上传送。前向纠错编码器和一个数字交错器电路38提高了经过具有噪声和干扰的信道之后的数据的完整性,在线40上生成了128kbps的数字信号。对于所传输的数字信号不是由模拟节目信号转变而来的情形,提供了数据端口42来接收数字信号。当模拟信号的数字形式,或输入端口42的数字信号需要包括一些额外数据时,辅助数据源44可用来满足这一要求。
数据分析器46接收数字数据,并在线48上生成多个输出。经过数据分析器46之后,线对48上的信号构成了复杂的系数,这些系数接着进入方框50所示的快速傅里所变换器中,分别在线52和线54上生成数字信号的基带同相分量I和正交分量Q,经过处理的基带模拟AM信号模/数变换器60后转变为数字信号,然后与数字DAB波形的同相部分在加法器62处合并,生成线64上的复合信号。线64上的复合信号经过一个数/模转换器66变为模拟信号,经低通滤波器68进行滤波,然后传送到混合器70,与一个由本地振荡器74生成的、位于线72上的无线频率信号相结合。线54上的正交信号由数/模变换器76转化为模拟信号,并经低通滤波器78进行滤波,经滤波后的信号在第二混合器80处与线82上的信号相结合。线72上的信号如方框84所示被移相,产生线82上的信号。混合器70和80的输出经线86和线88传送到加法器90,生成了线92上的复合波。最后的乱真混合产物由带送滤波器94进行静噪处理,所生成的DAB信号接着由功率放大器96进行放大,以传送到发送天线98处。
图3是图2中46所示的数据分析器的框图。数据分析器包括一个串并变换器100,该变换器接收串行数字信号,如图中输入线40所示,并且在多组线上生成多个输出数字信号,如图中线组102和104所示。每组线输送到一个QAM编码器,例如编码器106和108,生成同相输出信号I和正交输出信号Q。譬如,在实际应用中可以使每组具有5根线,使用76个QAM编码器。而且,一些QAM编码器可使用BPSK或QPSK。
图5是接收根据本发明播送的模拟和数字广播信号的接收机的结构框图。天线110接收包含数字信号和模拟信号在内的复合波,并将该信号输送到常规输入级112,该输入级可能包括一个射频预选器,一个放大器,一个混合器和一个本地振荡器。输入级生成一个中频信号送到线114上。该中频信号经自动增益控制电路116后,到达I/Q信号生成器118。I/Q信号生成器在线120上和线122上分别生成一个同相信号和一个正交信号。线120上的同相频道的输出被输入到一个模/数变换器124中。同时,线122上的正交频道输出被输入到另一个模/数变换器126中。线128和线130线的反馈信号被分别输入到数/模变换器132和134中,数/模变换器在线136和线138上的输出做为对自动增益控制电路116的控制信号。线120上的信号包括模拟AM信号,该信号由方框140所示被分离出,并传送到输出级142,进而连接到扬声器144上或其它输出设备上。
带阻滤波器146过滤线128上的同相分量,以消除模拟AM信号并在线148上提供一种经滤波的信号。快速傅里叶变换电路150接收线148和线152上的数字信号。并在线组154上生成输出信号。这些输出信号经过一个均衡器156和一个数据率滤波器和数据解码器158。数据解码器的输出被传送到一个去交错器和前向纠错解码电路164中,以提高数据的完整性。去交错器/前向纠错电路的输出被传送到源解码器166中,以生成线162上的信号,该信号被送到输出级142中。
本发明中使用一种AM DAB波形,它使把现有AM无线电台变为DAB时所必须的变化程度变到最小,因为其带宽在FCC所规定的AM传输辐射屏蔽的范围之内。因此,广播电台可以继续应用他们现有的发射天线。但他们现有的馈送网络则必须更新,因为信道的群延迟变化必须保持合理的恒定,以使数据信号符号间的干扰最少,但这种考虑比模拟AM信号传输时的考虑要不严格的多。但是只要功率放大器在恰当的线性模式下运行,现有的AM发射机估计是可以保留。主要的硬件改变将是以一个AM DAB激励器代替低电平载波输入。这一模块既产生AM DAB调制的数字部分又产生其模拟部分,因此发射机主要用来做为一个线性放大器。
尽管上述发明是参照AM数字声频广播***来描述,但是它应被看做一种可以在任何同时传送模拟与数字信号的***中应用的技术。而且,还应明确由数字信号所发送的信息可以和模拟调幅信号发送的信息不同。因此本发明的方法可以与调幅信号相结合发送各种数据,例如交通或天气信息,视频信号或军事通信信号,这种发明潜在的应用领域还包括调幅军事通信和视频信息是调幅的形式的电视信号中。
Claims (16)
1.一种射频广播方法,所述方法包括以下步骤:
发射一个具有第一频谱的射频信号,该信号中包括一个由模拟信号调幅的第一载波;
同时发射多个数字调制载波信号,这些信号存在于包括第一频谱的频段之内,每个所述的数字调制载波信号均由数字节目信号的一部分调制所得,其中,第一组所述的数字调制载波信号覆盖了所述的第一频谱,并被调制成与第一载波信号相正交,第二和第三组所述数字调制载波信号的频率在所述第一频谱之外,并均与第一载波信号同相和正交。
2.根据权利要求1的射频广播方法,其中:
所述的数字调制载波信号之间由所分配信道间隔的一个分谐波按频率进行间隔。
3.根据权利要求1的射频广播方法,其中:
在位于各相邻信道中心的数字调制载波信号位置上,没有发送能量。
4.根据权利要求1的射频广播方法,其中:
在所述第一组所述数字调制载波信号中的数字调制载波信号的幅度小于未调制第一载波信号的幅度。
5.根据权利要求4的射频广播方法,其中:
在所述第二和第三组所述数字调制载波信号中的数字调制载波信号的幅度小于未调制第一载波信号的幅度。
6.根据权利要求1的射频广播方法,其中:
在所述的数字调制载波信号中,选出与所述第一载波频率最接近的所述数字调制载波信号,对其进行BPSK调制。
7.根据权利要求6的射频广播方法,其中:
所述选出的所述数字调制载波信号做为所述数字载波信号中其它载波信号的参考电平。
8.根据权利要求1的射频广播方法,其中所述的模拟信号和所述的数字信号是对同一节目内容的不同表示方式。
9.根据权利要求1的射频广播方法,其中所述的第二和第三组所述数字载波信号为32-QAM调制。
10.根据权利要求1的射频广播方法,其中所述数字调制载波信号,位于一个占用40KHZ带宽的第二频谱中。
11.根据权利要求1的射频广播方法,其中所述数字调制载波信号频率的间隔是相等的。
12.根据权利要求11的射频广播方法,其中所述数字调制载波信号之间由所分配信道间隔的一个分谐波按频率进行间隔。
13.一种射频发射机,包括:
同时发射复合射频波的装置,其中复合波包括一个具有由模拟信号调幅的第一载波的第一信号,和一组数字调制载波信号,这些载波信号位于包括第一信号频谱的频段内,每种所述数字调制载波信号由数字信号的一部分数字调制所得,其中第一组所述的数字调制载波信号覆盖了第一信号频谱,并调制成与所述第一载波信号相正交,以及其中第二和第三组所述的数字调制载波信号的频率在所述的第一频谱之外,并均被调制成与第一载波信号同相和正交。
14.一种射频接收机,包括:
同时接收复合射频波中模拟和数字部分的装置,其中在该复合射频中包括一个具有由模拟信号调幅的第一载波的第一信号,和多个数字调制载波信号,这些载波信号存在于包括第一信号频谱的频段内,这种所述的数字调制载波信号均经由数字信号的一部分数字调制所得,其中第一组所述数字调制载波信号覆盖了第一信号的频谱,并被调制成与第一载波信号相正交,以及其中第二和第三组所述的数字调制载波信号的频率在第一信号的频谱之外,并均与第一载波信号同相和正交;
在所述第一调幅载波信号上检测所述模拟信号的装置;和
在所述数字调制载波上检测所述数字信号的信号。
15.根据权利要求14的射频接收机,其中检测所述数字信号的所述装置中,使用所述第一载波信号的相位作为对所述数字调制载波解调时的参考相位。
16.根据权利要求14的射频接收机,还包括:
用于从检测所述模拟信号的所述装置的同相信道中,分离所述模拟信号的滤波器。
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US08/206,368 US5588022A (en) | 1994-03-07 | 1994-03-07 | Method and apparatus for AM compatible digital broadcasting |
US08/206,368 | 1994-03-07 |
Related Child Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
CNB031314171A Division CN100358271C (zh) | 1994-03-07 | 1995-02-27 | 电信号调制方法以及发射模拟信号和数字信号的方法 |
Publications (2)
Publication Number | Publication Date |
---|---|
CN1146835A CN1146835A (zh) | 1997-04-02 |
CN1143463C true CN1143463C (zh) | 2004-03-24 |
Family
ID=22766069
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
CNB951919989A Expired - Lifetime CN1143463C (zh) | 1994-03-07 | 1995-02-27 | 调幅和数字共存的广播方法及装置 |
CNB031314171A Expired - Fee Related CN100358271C (zh) | 1994-03-07 | 1995-02-27 | 电信号调制方法以及发射模拟信号和数字信号的方法 |
Family Applications After (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
CNB031314171A Expired - Fee Related CN100358271C (zh) | 1994-03-07 | 1995-02-27 | 电信号调制方法以及发射模拟信号和数字信号的方法 |
Country Status (15)
Country | Link |
---|---|
US (1) | US5588022A (zh) |
EP (1) | EP0749650B1 (zh) |
JP (2) | JP4269003B2 (zh) |
KR (1) | KR100342286B1 (zh) |
CN (2) | CN1143463C (zh) |
AT (1) | ATE201540T1 (zh) |
AU (1) | AU687198B2 (zh) |
BR (1) | BR9507009A (zh) |
CA (1) | CA2185003C (zh) |
DE (1) | DE69521033T2 (zh) |
MX (1) | MX9603971A (zh) |
NZ (1) | NZ300094A (zh) |
RU (1) | RU2140708C1 (zh) |
TW (1) | TW256972B (zh) |
WO (1) | WO1995024781A1 (zh) |
Families Citing this family (86)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5465396A (en) | 1993-01-12 | 1995-11-07 | Usa Digital Radio Partners, L.P. | In-band on-channel digital broadcasting |
IL114471A0 (en) * | 1994-07-12 | 1996-01-31 | Usa Digital Radio Partners L P | Method and system for simultaneously broadcasting and analog signals |
US5956624A (en) | 1994-07-12 | 1999-09-21 | Usa Digital Radio Partners Lp | Method and system for simultaneously broadcasting and receiving digital and analog signals |
US6334219B1 (en) * | 1994-09-26 | 2001-12-25 | Adc Telecommunications Inc. | Channel selection for a hybrid fiber coax network |
US5631958A (en) * | 1994-10-04 | 1997-05-20 | Coherent Communications Systems Corp. | Automatic echo cancellation for an integrated services digital network interface |
DE19535075A1 (de) * | 1994-10-21 | 1996-04-25 | Deutsche Telekom Ag | Digitalmodulation |
JPH09509819A (ja) * | 1994-12-23 | 1997-09-30 | フィリップス エレクトロニクス ネムローゼ フェンノートシャップ | 一つのメモリのインタリーブ解除及び緩衝 |
US5668820A (en) * | 1995-01-23 | 1997-09-16 | Ericsson Inc. | Digital communication system having a punctured convolutional coding system and method |
US7280564B1 (en) | 1995-02-06 | 2007-10-09 | Adc Telecommunications, Inc. | Synchronization techniques in multipoint-to-point communication using orthgonal frequency division multiplexing |
USRE42236E1 (en) | 1995-02-06 | 2011-03-22 | Adc Telecommunications, Inc. | Multiuse subcarriers in multipoint-to-point communication using orthogonal frequency division multiplexing |
US5764706A (en) * | 1995-08-31 | 1998-06-09 | Usa Digital Radio Partners, L.P. | AM compatible digital waveform frame timing recovery and frame synchronous power measurement |
US5956373A (en) * | 1995-11-17 | 1999-09-21 | Usa Digital Radio Partners, L.P. | AM compatible digital audio broadcasting signal transmision using digitally modulated orthogonal noise-like sequences |
US5687191A (en) * | 1995-12-06 | 1997-11-11 | Solana Technology Development Corporation | Post-compression hidden data transport |
JPH09270765A (ja) * | 1996-01-31 | 1997-10-14 | Victor Co Of Japan Ltd | Ofdm変復調装置及びofdm変調方法 |
US5898732A (en) * | 1996-02-20 | 1999-04-27 | Usa Digital Radio Partners, L.P. | Data service channel provision for an AM compatible broadcast system |
US5901178A (en) * | 1996-02-26 | 1999-05-04 | Solana Technology Development Corporation | Post-compression hidden data transport for video |
JP3118419B2 (ja) * | 1996-06-07 | 2000-12-18 | 株式会社ケンウッド | Amデータ多重変調装置 |
US5949796A (en) * | 1996-06-19 | 1999-09-07 | Kumar; Derek D. | In-band on-channel digital broadcasting method and system |
US6144705A (en) * | 1996-08-22 | 2000-11-07 | Lucent Technologies Inc. | Technique for simultaneous communications of analog frequency-modulated and digitally modulated signals using precanceling scheme |
US5896421A (en) * | 1996-09-25 | 1999-04-20 | Hughes Electronics Corporation | Use of low pass filter and equalizer for noise reduction in direct up-conversion schemes |
US5930687A (en) * | 1996-09-30 | 1999-07-27 | Usa Digital Radio Partners, L.P. | Apparatus and method for generating an AM-compatible digital broadcast waveform |
US6359938B1 (en) * | 1996-10-31 | 2002-03-19 | Discovision Associates | Single chip VLSI implementation of a digital receiver employing orthogonal frequency division multiplexing |
FR2756686B1 (fr) * | 1996-11-29 | 1999-02-19 | Thomson Csf | Procede et dispositif de radiodiffusion mixte analogique et numerique d'emission radiophonique diffusee par un meme emetteur |
FR2757725B1 (fr) * | 1996-12-20 | 2001-10-05 | Thomson Csf | Procede hierarchique de transmission et de radiodiffusion numerique d'emission radiophoniques |
US5894497A (en) * | 1996-12-20 | 1999-04-13 | Airnet Communications Corp. | Reducing spurious modulation products in broadband multicarrier transmission by coherrent summation of the outputs of dissimilar digital-to analog device types |
TW465234B (en) | 1997-02-18 | 2001-11-21 | Discovision Ass | Single chip VLSI implementation of a digital receiver employing orthogonal frequency division multiplexing |
US6128334A (en) * | 1997-02-21 | 2000-10-03 | Usa Digital Radio, Inc. | Receiver addressable AM compatible digital broadcast system |
JPH10247855A (ja) * | 1997-03-04 | 1998-09-14 | Sony Corp | 放送信号受信装置 |
US6075813A (en) | 1997-03-18 | 2000-06-13 | Lucent Technologies Inc. | Band insertion and precancellation technique for simultaneous communication of analog frequency modulated and digitally modulated signals |
US6005894A (en) * | 1997-04-04 | 1999-12-21 | Kumar; Derek D. | AM-compatible digital broadcasting method and system |
DE19717169A1 (de) * | 1997-04-23 | 1998-10-29 | Deutsche Telekom Ag | Verfahren und Anordnung für eine analog-digitale Simultanübertragung von Rundfunksendungen in den AM-Frequenzbändern |
JPH1117760A (ja) * | 1997-06-24 | 1999-01-22 | Sony Corp | 受信装置及び送受信装置並びに通信方法 |
US5907582A (en) * | 1997-08-11 | 1999-05-25 | Orbital Sciences Corporation | System for turbo-coded satellite digital audio broadcasting |
US6148007A (en) * | 1998-03-27 | 2000-11-14 | Usa Digital Radio Partners, L.P. | Method for data transmission in a digital audio broadcasting system |
US6430227B1 (en) * | 1998-03-27 | 2002-08-06 | Ibiquity Digital Corporation | FM in-band-on-channel digital audio broadcasting method and system |
US6108810A (en) * | 1998-03-27 | 2000-08-22 | Usa Digital Radio, Inc. | Digital audio broadcasting method using puncturable convolutional code |
US6243424B1 (en) | 1998-03-27 | 2001-06-05 | Ibiguity Digital Corporation | Method and apparatus for AM digital broadcasting |
US6433835B1 (en) * | 1998-04-17 | 2002-08-13 | Encamera Sciences Corporation | Expanded information capacity for existing communication transmission systems |
US6445750B1 (en) * | 1998-04-22 | 2002-09-03 | Lucent Technologies Inc. | Technique for communicating digitally modulated signals over an amplitude-modulation frequency band |
JP3912459B2 (ja) * | 1998-06-16 | 2007-05-09 | ソニー株式会社 | 受信機 |
US6317470B1 (en) | 1998-09-15 | 2001-11-13 | Ibiquity Digital Corporation | Adaptive weighting method for orthogonal frequency division multiplexed soft symbols using channel state information estimates |
US6452977B1 (en) | 1998-09-15 | 2002-09-17 | Ibiquity Digital Corporation | Method and apparatus for AM compatible digital broadcasting |
US6292511B1 (en) | 1998-10-02 | 2001-09-18 | Usa Digital Radio Partners, Lp | Method for equalization of complementary carriers in an AM compatible digital audio broadcast system |
US6295317B1 (en) * | 1998-10-02 | 2001-09-25 | Usa Digital Radio Partners, Lp | Method and apparatus for demodulating and equalizing an AM compatible digital audio broadcast signal |
US6404408B1 (en) * | 1999-01-07 | 2002-06-11 | Surfer Network.Com, Inc. | Enhanced radio graphic data system |
US6590944B1 (en) | 1999-02-24 | 2003-07-08 | Ibiquity Digital Corporation | Audio blend method and apparatus for AM and FM in band on channel digital audio broadcasting |
US6567474B1 (en) * | 1999-03-02 | 2003-05-20 | Phonex Corporation | Digital wireless phone/modem jack capable of communications over the power lines using differential binary phase shift keying (DBPSK) |
US6556639B1 (en) | 1999-06-24 | 2003-04-29 | Ibiquity Digital Corporation | Method and apparatus for determining transmission mode and synchronization for a digital audio broadcasting signal |
US6400758B1 (en) | 1999-06-24 | 2002-06-04 | Ibiquity Digital Corporation | Method and apparatus for training sequence identification in an AM compatible digital audio broadcasting system |
US6532258B1 (en) | 1999-06-24 | 2003-03-11 | Ibiquity Digital Corporation | Method for estimating signal-to-noise ratio of digital carriers in an AM compatible digital audio broadcasting system |
DE19932062A1 (de) * | 1999-07-12 | 2001-01-18 | Bosch Gmbh Robert | Verfahren zur Aufbereitung von quellcodierten Audiodaten sowie Sender und Empfänger hierzu |
US6721337B1 (en) | 1999-08-24 | 2004-04-13 | Ibiquity Digital Corporation | Method and apparatus for transmission and reception of compressed audio frames with prioritized messages for digital audio broadcasting |
US6879640B1 (en) * | 1999-10-20 | 2005-04-12 | Broadcom Corporation | Method, apparatus and system for high-speed transmission on fiber optic channel |
US7095793B2 (en) * | 2000-01-07 | 2006-08-22 | Mario Hieb | Digital exciter/phasor/transmitter for directional antennal system |
US20020009125A1 (en) * | 2000-06-12 | 2002-01-24 | Shi Zhen Liang | High bandwidth efficient spread spectrum modulation using chirp waveform |
DE10131849A1 (de) | 2001-06-27 | 2003-01-16 | Deutsche Telekom Ag | Verfahren zur Vermeidung von Störausstrahlungen bei AM-Sendern für digitale Übertragung |
EP1276257B1 (en) * | 2001-07-11 | 2003-06-04 | Sony International (Europe) GmbH | DRM/AM simulcast |
US20030191151A1 (en) * | 2001-10-26 | 2003-10-09 | Imtiaz Chaudry | Albuterol and ipratropium inhalation solution, system, kit and method for relieving symptoms of chronic obstructive pulmonary disease |
US6798849B2 (en) | 2001-12-10 | 2004-09-28 | Ibiquity Digital Corporation | AM digital audio broadcasting with analog signal pre-compensation |
US6639949B2 (en) | 2001-12-17 | 2003-10-28 | Ibiquity Digital Corporation | Method and apparatus for pulse overlap pre-compensation in digitally modulated signals |
US7043681B2 (en) | 2002-05-03 | 2006-05-09 | Ibiquity Digital Corporation | Digital audio broadcasting method and apparatus using complementary pattern-mapped convolutional codes |
EP1370017A1 (en) * | 2002-06-07 | 2003-12-10 | Sony International (Europe) GmbH | Interference reduction for simulcast signals |
US7551675B2 (en) * | 2002-09-27 | 2009-06-23 | Ibiquity Digital Corporation | Method and apparatus for synchronized transmission and reception of data in a digital audio broadcasting system |
AR041413A1 (es) * | 2002-09-27 | 2005-05-18 | Ibiquity Digital Corp | Metodo y aparato para la transmision digital de audio |
US7305043B2 (en) * | 2002-10-17 | 2007-12-04 | Ibiquity Digital Corporation | Method and apparatus for formatting signals for digital audio broadcasting transmission and reception |
US6898249B2 (en) * | 2002-12-17 | 2005-05-24 | Ibiquity Digital Corporation | Method and apparatus for AM digital audio broadcasting with amplitude scaled tertiary subcarriers |
JP2006518155A (ja) * | 2003-02-14 | 2006-08-03 | フォーカス エンハンスメンツ インコーポレイテッド | 周波数分割多重方法とそのための装置 |
US7127008B2 (en) | 2003-02-24 | 2006-10-24 | Ibiquity Digital Corporation | Coherent AM demodulator using a weighted LSB/USB sum for interference mitigation |
US7460684B2 (en) | 2003-06-13 | 2008-12-02 | Nielsen Media Research, Inc. | Method and apparatus for embedding watermarks |
US7340010B2 (en) * | 2004-01-26 | 2008-03-04 | Ibiquity Digital Corporation | Forward error correction coding for hybrid AM in-band on-channel digital audio broadcasting systems |
US7680201B2 (en) * | 2004-01-26 | 2010-03-16 | Ibiquity Digital Corporation | Forward error correction coding for AM 9kHz and 10kHz in-band on-channel digital audio broadcasting systems |
CN100380821C (zh) * | 2004-02-12 | 2008-04-09 | 北京新岸线移动多媒体技术有限公司 | 向下兼容的调幅广播数字化传输方法 |
NZ552644A (en) | 2004-07-02 | 2008-09-26 | Nielsen Media Res Inc | Methods and apparatus for mixing compressed digital bit streams |
DE102004032286A1 (de) * | 2004-07-02 | 2006-01-19 | Robert Bosch Gmbh | Verfahren und Vorrichtung zur Übertragung von Zusatzdaten in einem analogen Rundfunkübertragungssystem |
US7233777B2 (en) * | 2004-08-31 | 2007-06-19 | L-3 Integrated Systems Company | Separation of AM cochannel signals in an overloaded signal environment |
US7426378B2 (en) * | 2005-04-05 | 2008-09-16 | L-3 Communications Integrated Systems, L.P. | Separation of cochannel FM signals |
US7697620B2 (en) | 2005-11-14 | 2010-04-13 | Ibiquity Digital Corporation | Equalizer for AM in-band on-channel radio receivers |
US7733983B2 (en) * | 2005-11-14 | 2010-06-08 | Ibiquity Digital Corporation | Symbol tracking for AM in-band on-channel radio receivers |
US8306476B2 (en) * | 2007-07-18 | 2012-11-06 | Griffin Technology, Inc. | Digital controller and transmitter for portable electronic device |
US7623833B2 (en) * | 2006-04-13 | 2009-11-24 | Harris Corporation | Dual output digital exciter |
WO2008045950A2 (en) | 2006-10-11 | 2008-04-17 | Nielsen Media Research, Inc. | Methods and apparatus for embedding codes in compressed audio data streams |
RU2505925C2 (ru) * | 2012-01-17 | 2014-01-27 | Игорь Владимирович Заикин | Способ одновременного излучения аналогового и цифрового сигнала вч от одного передатчика |
US8595590B1 (en) | 2012-12-03 | 2013-11-26 | Digital PowerRadio, LLC | Systems and methods for encoding and decoding of check-irregular non-systematic IRA codes |
US9191256B2 (en) | 2012-12-03 | 2015-11-17 | Digital PowerRadio, LLC | Systems and methods for advanced iterative decoding and channel estimation of concatenated coding systems |
US8948272B2 (en) | 2012-12-03 | 2015-02-03 | Digital PowerRadio, LLC | Joint source-channel decoding with source sequence augmentation |
CN110441741A (zh) * | 2019-07-11 | 2019-11-12 | 纳瓦电子(上海)有限公司 | 一种实现正交幅度调制的方法 |
Family Cites Families (31)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3845391A (en) * | 1969-07-08 | 1974-10-29 | Audicom Corp | Communication including submerged identification signal |
US3919479A (en) * | 1972-09-21 | 1975-11-11 | First National Bank Of Boston | Broadcast signal identification system |
US3885217A (en) * | 1973-07-11 | 1975-05-20 | Computer Specifics Corp | Data transmission system |
US3919640A (en) * | 1974-11-08 | 1975-11-11 | Northern Illinois Gas Co | Simultaneous analog and digital data transfer |
US4051438A (en) * | 1975-09-11 | 1977-09-27 | International Telephone And Telegraph Corporation | Co-channel multiple signal broadcasting system |
FR2464601B1 (fr) * | 1979-08-29 | 1986-10-24 | Trt Telecom Radio Electr | Systeme de radiodiffusion numerique de plusieurs signaux d'information par un reseau d'emetteurs utilisant sensiblement la meme frequence porteuse |
DE3121146A1 (de) * | 1981-05-27 | 1983-01-05 | Siemens AG, 1000 Berlin und 8000 München | Digitales funksystem |
US4399558A (en) * | 1981-06-29 | 1983-08-16 | Rca Corporation | Cascaded digital broadcast transmitter |
US4425642A (en) * | 1982-01-08 | 1984-01-10 | Applied Spectrum Technologies, Inc. | Simultaneous transmission of two information signals within a band-limited communications channel |
FR2539261B1 (fr) * | 1983-01-07 | 1989-07-13 | Telecommunications Sa | Emetteur pour faisceaux hertziens numeriques a multi-etats |
US4665427A (en) * | 1983-03-14 | 1987-05-12 | U.S. Philips Corporation | Method and apparatus for converting C-MAC television signals for transmission over a limited bandwidth medium |
US4881245A (en) * | 1983-07-01 | 1989-11-14 | Harris Corporation | Improved signalling method and apparatus |
AU589119B2 (en) * | 1984-04-17 | 1989-10-05 | Nec Corporation | Digital radio communication system utilizing quadrature modulated carrier waves |
EP0182843A1 (en) * | 1984-05-29 | 1986-06-04 | Mesh Data Limited | Data transmission method and apparatus |
US4615040A (en) * | 1984-06-14 | 1986-09-30 | Coenco Ltd. | High speed data communications system |
US4660192A (en) * | 1985-04-11 | 1987-04-21 | Pomatto Sr Robert P | Simultaneous AM and FM transmitter and receiver |
US5128933A (en) * | 1985-07-29 | 1992-07-07 | Baranoff Rossine Dimitri | Process and device for the radio transmission of coded data superimposed on a traditional frequency-modulated broadcast |
US4882725A (en) * | 1987-01-30 | 1989-11-21 | Hitachi, Ltd. | Multiplex transmission method and apparatus |
US4881241A (en) * | 1988-02-24 | 1989-11-14 | Centre National D'etudes Des Telecommunications | Method and installation for digital communication, particularly between and toward moving vehicles |
FI83005C (fi) * | 1988-08-19 | 1991-05-10 | Nokia Mobira Oy | Kretsanordning foer generering av i,q-vaogformer. |
US5006926A (en) * | 1988-10-03 | 1991-04-09 | North American Philips Corporation | High definition multiple analog component amplitude modulated television transmission system |
US5134630A (en) * | 1989-04-12 | 1992-07-28 | National Research Development Corporation | Method and apparatus for transparent tone-in-band transmitter, receiver and system processing |
US5134634A (en) * | 1989-08-31 | 1992-07-28 | Nec Corporation | Multilevel quadrature amplitude demodulator capable of compensating for a quadrature phase deviation of a carrier signal pair |
FR2658016B1 (fr) * | 1990-02-06 | 1994-01-21 | Etat Francais Cnet | Procede de diffusion de donnees numeriques, notamment pour la radiodiffusion a haut debit vers des mobiles, a entrelacement temps-frequence et demodulation coherente, et recepteur correspondant. |
US5179576A (en) * | 1990-04-12 | 1993-01-12 | Hopkins John W | Digital audio broadcasting system |
US5291289A (en) * | 1990-11-16 | 1994-03-01 | North American Philips Corporation | Method and apparatus for transmission and reception of a digital television signal using multicarrier modulation |
US5278826A (en) * | 1991-04-11 | 1994-01-11 | Usa Digital Radio | Method and apparatus for digital audio broadcasting and reception |
US5315583A (en) * | 1991-04-11 | 1994-05-24 | Usa Digital Radio | Method and apparatus for digital audio broadcasting and reception |
US5333155A (en) * | 1991-04-25 | 1994-07-26 | Rohde & Schwarz Gmbh & Co. Kg | Method and system for transmitting digital audio signals from recording studios to the various master stations of a broadcasting network |
DE4125606A1 (de) * | 1991-08-02 | 1993-02-04 | Rohde & Schwarz | Verfahren zum uebertragen von digitalen hdtv-signalen |
JP2904986B2 (ja) * | 1992-01-31 | 1999-06-14 | 日本放送協会 | 直交周波数分割多重ディジタル信号送信装置および受信装置 |
-
1994
- 1994-03-07 US US08/206,368 patent/US5588022A/en not_active Expired - Lifetime
-
1995
- 1995-02-27 CN CNB951919989A patent/CN1143463C/zh not_active Expired - Lifetime
- 1995-02-27 EP EP95913961A patent/EP0749650B1/en not_active Expired - Lifetime
- 1995-02-27 JP JP52349595A patent/JP4269003B2/ja not_active Expired - Lifetime
- 1995-02-27 AT AT95913961T patent/ATE201540T1/de not_active IP Right Cessation
- 1995-02-27 CN CNB031314171A patent/CN100358271C/zh not_active Expired - Fee Related
- 1995-02-27 WO PCT/US1995/002408 patent/WO1995024781A1/en active IP Right Grant
- 1995-02-27 DE DE69521033T patent/DE69521033T2/de not_active Expired - Lifetime
- 1995-02-27 KR KR1019960704895A patent/KR100342286B1/ko not_active IP Right Cessation
- 1995-02-27 RU RU96120156A patent/RU2140708C1/ru active
- 1995-02-27 NZ NZ300094A patent/NZ300094A/en not_active IP Right Cessation
- 1995-02-27 AU AU23745/95A patent/AU687198B2/en not_active Expired
- 1995-02-27 CA CA002185003A patent/CA2185003C/en not_active Expired - Lifetime
- 1995-02-27 BR BR9507009A patent/BR9507009A/pt not_active IP Right Cessation
- 1995-03-03 TW TW084102021A patent/TW256972B/zh active
-
1996
- 1996-09-06 MX MX9603971A patent/MX9603971A/es unknown
-
2007
- 2007-11-14 JP JP2007295825A patent/JP4269014B2/ja not_active Expired - Lifetime
Also Published As
Publication number | Publication date |
---|---|
EP0749650A1 (en) | 1996-12-27 |
JP4269003B2 (ja) | 2009-05-27 |
ATE201540T1 (de) | 2001-06-15 |
KR970701977A (ko) | 1997-04-12 |
CA2185003A1 (en) | 1995-09-14 |
CA2185003C (en) | 2005-01-04 |
EP0749650B1 (en) | 2001-05-23 |
JP2008125088A (ja) | 2008-05-29 |
DE69521033D1 (de) | 2001-06-28 |
AU687198B2 (en) | 1998-02-19 |
NZ300094A (en) | 1998-01-26 |
US5588022A (en) | 1996-12-24 |
CN100358271C (zh) | 2007-12-26 |
BR9507009A (pt) | 1997-09-16 |
JPH10500810A (ja) | 1998-01-20 |
JP4269014B2 (ja) | 2009-05-27 |
AU2374595A (en) | 1995-09-25 |
RU2140708C1 (ru) | 1999-10-27 |
WO1995024781A1 (en) | 1995-09-14 |
MX9603971A (es) | 1998-11-30 |
DE69521033T2 (de) | 2001-11-08 |
CN1146835A (zh) | 1997-04-02 |
KR100342286B1 (ko) | 2002-11-29 |
TW256972B (zh) | 1995-09-11 |
CN1496034A (zh) | 2004-05-12 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
CN1143463C (zh) | 调幅和数字共存的广播方法及装置 | |
US6452977B1 (en) | Method and apparatus for AM compatible digital broadcasting | |
CN1221115C (zh) | 确定数字音频广播信号的发送模式和同步的方法和装置 | |
US6144705A (en) | Technique for simultaneous communications of analog frequency-modulated and digitally modulated signals using precanceling scheme | |
EP0658295B1 (en) | Digital signal transmission system using frequency division multiplex | |
EP0571005B1 (en) | Method and system for transmission and reception of a digital television signal using multicarrier modulation | |
CN1125542C (zh) | Fm带内-信道上的数字声频广播方法和*** | |
US6128334A (en) | Receiver addressable AM compatible digital broadcast system | |
EP1041756B1 (en) | Multistream-in-band-on-channel transmission system | |
US5898732A (en) | Data service channel provision for an AM compatible broadcast system | |
WO1995002289A1 (en) | Multiresolution ofdm | |
IL114173A (en) | Method and apparatus for am compatible digital broadcasting | |
EP0976209A1 (en) | Signalling method and transmitter used in a digital radio system | |
CA2321941A1 (en) | Technique for simultaneous communications of analog frequency-modulated and digitally modulated signals using precanceling scheme | |
Bernatek | Perceptual audio coding for digital sound broadcasting |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
C06 | Publication | ||
PB01 | Publication | ||
C10 | Entry into substantive examination | ||
SE01 | Entry into force of request for substantive examination | ||
C53 | Correction of patent of invention or patent application | ||
COR | Change of bibliographic data |
Free format text: CORRECT: APPLICANT; FROM: WESTINGHOUSE ELECTRIC CORP. TO: USA DIGITAL RADIO COMMUNICATION PARTNER CORPORATION |
|
CP03 | Change of name, title or address |
Address after: American New York Applicant after: USA digital radio communication partnership Address before: American Ohio Applicant before: Westinghouse Electric Corp. |
|
C14 | Grant of patent or utility model | ||
GR01 | Patent grant | ||
C17 | Cessation of patent right | ||
CX01 | Expiry of patent term |
Expiration termination date: 20150227 Granted publication date: 20040324 |