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Dual mode radio frequency reception device and corresponding multimedia receiverRelated Patent Categories: Telecommunications, Receiver Or Analog Modulated Signal Frequency Converter, Frequency Or Phase Modulation, With Plural ConversionDual mode radio frequency reception device and corresponding multimedia receiver description/claimsThe Patent Description & Claims data below is from USPTO Patent Application 20060240793, Dual mode radio frequency reception device and corresponding multimedia receiver. Brief Patent Description - Full Patent Description - Patent Application Claims
[0001] The domain of this invention is multimedia receivers, and particularly portable receivers. More precisely, the invention relates to receivers capable of receiving firstly multi-carrier broadcast signals, and secondly radio positioning signals. [0002] This type of multimedia receiver has been developed particularly within the framework of the European MEDEA A222 "Components for portable multimedia systems" project. This type of receiver is planned to include firstly DAB (Digital Audio Broadcasting) signal reception means, and secondly GPS (Global Positioning System) signal reception means. [0003] The DAB system is a digital data broadcasting system, the first purpose of which was to replace the current FM radio. One of the objectives was then to offer improved sound quality, referred to as "digital" and accompanied by text information. [0004] The DAB system uses COFDM modulation. According to the standard currently used, its spectrum occupies 23 channels distributed on a 39.2 MHz frequency band. The width of a DAB channel is 1.536 MHz, and the spacing between channels is 176 kHz. The reception level varies between -90 dBm and +8 dBm. [0005] Each DAB channel is surrounded by adjacent channels, the level of which may be 40 dB above the useful channel, or even 70 dB for remote channels (I/C=40 dB to 70 dB). The range of the input signal, and the presence of adjacent channels, make the use of controlled gain amplifiers (CGA) and selective filters necessary. An analog-digital converter with a sufficiently wide range could reduce the constraints on the first two parameters through the use of digital filters and CGAs that are easier to make. The receiver must be sufficiently selective to extract the useful signal, and the range must be sufficiently wide to accept variations in the reception signal. [0006] In particular, the following documents describe examples of DAB receivers: [0007] Ward Titus, Rosa Croughwell, Chris Schiller, Larry DeVito, "A Si BJT Dual Band Receiver IC for DAB", Radio Frequency Integrated Circuits Symposium, 1998, pp. 297-300; [0008] Marc Goldfarb, Rosa Croughwell, Chris Schiller, Darell Livezey, George Heiter, "A Si BJT IF Down Converter/AGC IC for DAB", Radio Frequency Integrated Circuits Symposium, 1998, pp. 305-308; [0009] M. Bolle, K. Gieske, F. Hoffmann, T. Mlasko, G. [0010] Spreitz, "D-FIRE: A DAB Receiver System on a Chip", Proceedings of ESSCIRC'98, 1998, pp. 360-363. [0011] A DAB receiver can receive audio, video and/or text type data, such that it performs the functions of a multimedia terminal. [0012] The addition of other services such as the GPS system makes it possible to develop other interesting applications. [0013] Thus, reception of a GPS signal in order to precisely determine the location of the receiver, is a means of directly developing navigation assistance applications, with the multimedia terminal informing the user of his position on a geographic map downloaded through the DAB channel. Within the framework of an automobile application, the DAB broadcast can provide information about traffic jams and accidents. Positioning using GPS is a means of determining a new route. [0014] It should be noted that the GPS signal uses spectrum spreading modulation. [0015] Two types of GPS signals are emitted on two channels at different frequencies, L1=1575.42 MHz and L2=1227.6 MHz. The L2 channel broadcasts a signal used for military purposes (P code) and occupies a 20 MHz band. The L1 channel emits a signal for civil applications (C/A code) that occupies a 2 MHz band. [0016] Therefore, multimedia receivers only use this L1 channel. The reception level of the GPS signal for this channel is about -130 dBm, which is 19 dB below the thermal noise (about -111 dBm on a 2 MHz band). [0017] After correlating the GPS signal with the spreading sequence (despreading), the GPS signal occupies a 50 Hz band with a 43 dB gain. Since the correlation operation is made within the digital range, the analog-digital conversion is not a very sensitive point. In general, a single 1-bit ADC is used in order to eliminate the need for a controlled gain amplifier (CGA). [0018] The overriding problem is the noise level added in the band after quantification of the signal. If a single 1-bit quantifier is used, the range of its input signal must be sufficiently low so that the quantification noise is not too high. This aspect requires appropriate filtering of disturbing sources and/or oversampling of the very low level signal, and a high gain (about 100 dB) so that the ADC can process the GPS signal level. [0019] The following documents describe examples of GPS receivers: [0020] Anna M. Murphy, Shinichi Tsutsumi, Peter Gaussen, "A Low Power, Low-Cost Bipolar GPS Receiver Chip", IEEE Journal of Solid-State Circuits, vol. 32, No. 4, April 1997, pp. 587-591; [0021] Arvin R. Shahani, Derek K., Shaeffer, Thomas H. Lee, "A 12-mW Wide Dynamic Range CMOS Front-End for a Portable GPS Receiver", IEEE Journal of Solid State Circuits, vol. 32, No. 12, December 1997, pp. 2061-2070; [0022] Francesco Piazza, Qiuting, Huang, A 1.75-GHz RF Front-End for Triple Conversion GPS Receiver", IEEE Journal of Solid-State Circuits, vol. 33, No. 2, February 1998, pp. 202-209; [0023] D. Shaeffer, A. Shahani, S. Mohan, H. Samavati, H. Rategh, M. Hershenson, M. Xu, C. Yue, D. Eddleman, T. Lee, "A 115 mW CMOS GPS Receiver", Proceedings of ISSCC'98, Session 8, February 1998, pp. 122-123. [0024] At the present time in known multimedia reicevers, each proposed service (DAB and GPS) has its own radio frequency reception system. Therefore two radio frequency reception systems are simply placed side by side in the same casing, possibly sharing a common power supply. Obviously, this means increased complexity and consumption. [0025] In particular, the purpose of the invention is to overcome this disadvantage in prior art. [0026] More precisely, one purpose of the invention is to provide a dual mode reception device enabling reception firstly of multi-carrier broadcast signals (for example DAB) and secondly radio positioning signals (for example GPS) under optimum conditions, particularly for consumption, size and complexity of the means used. [0027] Thus, one particular purpose of the invention is to provide this type of device that has a sufficiently low consumption so that it can be implemented in the form of a portable multimedia receiver. [0028] Obviously, another purpose of the invention is to provide such a reception device at a low cost price compared with known receivers, as a result of its lower technical complexity. [0029] Another purpose of the invention is to provide this type of reception device with good reception qualities despite the cohabitation of two radio frequency systems. [0030] These purposes, and others that will become clear later, are achieved using a dual mode radio frequency reception device of the type enabling reception firstly of multi-carrier broadcast signals in a first frequency band, and secondly radio positioning signals in a second frequency band. [0031] According to the invention, this device comprises a single preprocessing module, particularly including a pass-band antenna filter in which the pass-band includes at least the said first and second frequency bands, and outputting firstly to a first processing system for the said multi-carrier broadcast signals, and secondly to a second system for processing the said radio positioning signals. Continue reading about Dual mode radio frequency reception device and corresponding multimedia receiver... Full patent description for Dual mode radio frequency reception device and corresponding multimedia receiver Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Dual mode radio frequency reception device and corresponding multimedia receiver patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. 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