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公开(公告)号：EP1712051B1
公开(公告)日：2007-10-31
申请号：EP05705538.6
申请日：2005-01-12
IPC分类号： H04L27/26
CPC分类号： H04L27/2623 , H04L27/2624 , H04L27/2626
摘要： A method of reducing peak-to-average power ratio in an OFDM signal comprises the steps of modulating a set of subcarriers with a set of data symbol vectors to produce a first modulated signal, limiting the magnitude of the first modulated signal to produce a first limited modulated signal, demodulating the first limited modulated signal to recover distorted input symbol vectors, constraining the distorted input symbol vectors to values greater than or equal to a minimum threshold value to produce constrained data symbol vectors, constraining out-of-band spectral components to lie within a predetermined mask, and remodulating the constrained data symbol vectors. A transmitter that performs the method is also included.
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2.发明公开COHERENT TRACKING FOR FM IBOC RECEIVER USING A SWITCH DIVERSITY ANTENNA SYSTEM 审中-公开FOR A FM IBOC接收器选择相干跟踪通过使用开关集式天线装置
公开(公告)号：EP1685688A2
公开(公告)日：2006-08-02
申请号：EP04810923.5
申请日：2004-11-12
CPC分类号： H04L27/2655 , H04L25/0224 , H04L27/2675
摘要： A method is provided for coherently tracking a radio signal including a plurality of digitally modulated reference subcarriers. The method comprises the steps of receiving symbols transmitted on the reference subcarriers, combining the reference subcarrier symbols with a known reference sequence conjugate to produce a plurality of samples, median filtering the samples to produce filtered samples, and smoothing the samples for each of the reference subcarriers over the plurality of reference subcarriers to produce a coherent reference signal estimate for each of the subcarriers. A receiver for coherently tracking a radio signal including at least one digitally modulated reference carrier is also provided.
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3.发明授权METHOD AND APPARATUS FOR TRANSMISSION AND RECEPTION OF FM IN-BAND ON-CHANNEL DIGITAL AUDIO BROADCASTING 有权方法和设备，它声道数字音频广播发射和接收信号的FM波段
公开(公告)号：EP1232591B1
公开(公告)日：2005-08-24
申请号：EP00993065.2
申请日：2000-11-10
IPC分类号： H04H1/00
CPC分类号： H04L27/2613 , H04H20/30 , H04H2201/183 , H04H2201/20 , H04L1/004 , H04L5/0048 , H04L25/0226 , H04L25/0228 , H04L25/03159 , H04L27/2071 , H04L27/2655
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4.发明公开METHOD FOR ALIGNMENT OF ANALOG AND DIGITAL AUDIO IN A HYBRID RADIO WAVEFORM 审中-公开方法同步数字音频模拟，并在混合无线电信号方式
公开(公告)号：EP1867078A1
公开(公告)日：2007-12-19
申请号：EP06721125.0
申请日：2006-03-01
IPC分类号： H04H1/00
CPC分类号： H04H20/30 , H04H20/12 , H04H2201/183 , H04H2201/186
摘要： This invention provides a method of detecting time alignment of an analog audio signal and a digital audio signal in a hybrid radio system. The method comprises the steps of filtering the analog audio signal to produce a filtered analog audio signal, filtering the digital audio signal to produce a filtered digital audio signal, and using the filtered analog audio signal and the filtered digital audio signal to calculate a plurality of correlation coefficients, wherein the correlation coefficients are representative of time alignment between the analog audio signal and the digital audio signal. An apparatus for performing the method is also provided.
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5.发明公开COHERENT AM DEMODULATOR USING A WEIGHTED LSB/USB SUM FOR INTERFERENCE MITIGATION 有权带权LSB / USB SUM相干AM解调器减少干扰
公开(公告)号：EP1597820A2
公开(公告)日：2005-11-23
申请号：EP04706512.3
申请日：2004-01-29
IPC分类号： H03D1/24
CPC分类号： H03D1/2245 , H03D1/04
摘要： A method of processing an AM radio signal comprises the step of receiving an AM radio signal including an upper sideband portion and a lower sideband portion, demodulating the upper sideband portion and the lower sideband portion to produce a demodulated upper sideband signal and a demodulated lower sideband signal, weighting the demodulated upper sideband signal and the demodulated lower sideband signal in response to noise power to produce a weighted demodulated upper sideband signal and a weighted demodulated lower sideband signal, and combining the weighted demodulated upper sideband signal and the weighted demodulated lower sideband signal to produce an output signal. Demodulators which process AM radio signals in accordance with the method, and receivers incorporating the demodulators, are also included.
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6.发明授权METHOD AND APPARATUS FOR REDUCING PEAK TO AVERAGE POWER RATIO IN DIGITAL BROADCASTING SYSTEMS 有权方法和装置减少了高峰和中等绩效之间的关系在数字广播系统
公开(公告)号：EP1206866B1
公开(公告)日：2005-10-26
申请号：EP00957735.4
申请日：2000-08-23
IPC分类号： H04L27/26
CPC分类号： H04L27/2624
摘要： This invention provides a method for reducing peak to average power ratio in a radio frequency signal. The method comprises the steps of modulating a plurality of subcarriers with a plurality of data symbol vectors to produce a first modulated signal; limiting the magnitude of the first modulated signal to produce a first limited modulated signal; demodulating the first limited modulated signal to recover the constellation points; predistorting the data symbol vectors to provide a minimum magnitude for in-phase and quadrature components thereof to produce predistorted data symbol vectors; modulating the plurality of carriers with the predistorted data symbol vectors to produce a second modulated signal; limiting the magnitude the second modulated signal to produce a second limited modulated signal; and reducing intermodulation products in the second limited modulated signal. Transmitters that perform the method are also included.
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7.发明授权COHERENT AM DEMODULATOR USING A WEIGHTED LSB/USB SUM FOR INTERFERENCE MITIGATION 有权带权LSB / USB SUM相干AM解调器减少干扰
公开(公告)号：EP1597820B1
公开(公告)日：2007-07-25
申请号：EP04706512.3
申请日：2004-01-29
IPC分类号： H03D1/24
CPC分类号： H03D1/2245 , H03D1/04
摘要： A method of processing an AM radio signal comprises the step of receiving an AM radio signal including an upper sideband portion and a lower sideband portion, demodulating the upper sideband portion and the lower sideband portion to produce a demodulated upper sideband signal and a demodulated lower sideband signal, weighting the demodulated upper sideband signal and the demodulated lower sideband signal in response to noise power to produce a weighted demodulated upper sideband signal and a weighted demodulated lower sideband signal, and combining the weighted demodulated upper sideband signal and the weighted demodulated lower sideband signal to produce an output signal. Demodulators which process AM radio signals in accordance with the method, and receivers incorporating the demodulators, are also included.
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8.发明公开METHOD AND APPARATUS FOR TRANSMISSION AND RECEPTION OF COMPRESSED AUDIO FRAMES WITH PRIORITIZED MESSAGES FOR DIGITAL AUDIO BROADCASTING 审中-公开方法和设备用于数字音频广播优先级新闻传播和接收的压缩音频刚架
公开(公告)号：EP1206857A2
公开(公告)日：2002-05-22
申请号：EP00959335.1
申请日：2000-08-23
IPC分类号： H04H1/00
CPC分类号： H04H20/30 , H04H2201/20
摘要： A method for transmission of compressed data for a digital audio broadcasting system comprises the steps of producing digital information representative of an audio signal; estimating the number of bits to be allocated to the digital information in a modem frame; encoding the digital information within the estimated number of bits to produce encoded data; removing selected bits from the encoded data; adding bits corresponding to digital messages to the encoded information to form a composite modem frame; formatting the composite modem frame bits to produce formatted composite modem frame bits; and transmitting the formatted composite modem frame bits. The invention also encompasses transmitters that perform the method.
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9.发明公开METHOD AND APPARATUS FOR REDUCTION OF FM INTERFERENCE FOR FM IN-BAND ON-CHANNEL DIGITAL AUDIO BROADCASTING SYSTEM 有权方法和设备的干扰减少对于FM调频IN-BAND数字音频广播
公开(公告)号：EP1125384A2
公开(公告)日：2001-08-22
申请号：EP99965739.8
申请日：1999-10-28
CPC分类号： H04B1/109 , H04H40/27 , H04H2201/183 , H04L25/03006
摘要： This invention provides a method for reducing FM interference in an in-band on-channel digital audio broadcasting system. The method includes the steps of receiving a composite signal including a signal of interest and an interfering signal and normalizing the composite signal to produce a normalized composite signal. The composite signal is then multiplied by the complex conjugate of the normalized composite signal to produce a real signal. Then the real signal is filtered and the resulting filtered signal is multiplied by the normalized composite signal to produce an output signal. The adverse effects of the interfering signal in the output signal are reduced with respect to the magnitude of the signal of interest reducing FM interference in an in-band on-channel digital audio broadcasting system, thereby making it easier to detect the signal of interest. The output signal and the composite can be blended in response to the power of the real and filtered signals. Radio receivers that utilize the above method are also included.
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公开(公告)号：EP1101302A1
公开(公告)日：2001-05-23
申请号：EP99908545.9
申请日：1999-02-24
IPC分类号： H04H1/00
CPC分类号： H04H20/30 , H04H2201/186
摘要： A method for AM in-band-on-channel (IBOC) digital audio broadcasting (DAB) uses a center channel signal in a central frequency band (18) of an AM radio channel, the center channel signal is modulated by first and second versions of the program material to be transmitted. Sub-carriers in upper and lower sidebands (20, 22) of the AM radio channel are modulated with addition digitally encoded portions of the program material. The upper sideband (20) lies within a frequency band extending from about +5 kHz to about +10 kHz from a center frequency of the radio channel and the lower sideband (22) lying within a frequency band extending from about -5 kHz to about -10 kHz from the center frequency of the radio channel. The center channel signal and the upper and lower sideband sub-carriers are transmitted to receivers. In a hybrid IBOC DAB version, the center channel signal includes a carrier which is analog modulated by the first version of the program material and additional sub-carriers modulated by the second version of the program material, wherein the additional sub-carriers are transmitted at a power spectral density level that is less than the power spectral density of the analog modulated carrier. In an all-digital version, the center channel signal includes two groups of sub-carriers modulated with the program material.
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