Classifications

• • 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
  • H04H20/30—Arrangements for simultaneous broadcast of plural pieces of information by a single channel
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04H—BROADCAST COMMUNICATION
  • H04H20/00—Arrangements for broadcast or for distribution combined with broadcast
  • H04H20/44—Arrangements characterised by circuits or components specially adapted for broadcast
  • H04H20/46—Arrangements characterised by circuits or components specially adapted for broadcast specially adapted for broadcast systems covered by groups H04H20/53-H04H20/95
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04H—BROADCAST COMMUNICATION
  • H04H20/00—Arrangements for broadcast or for distribution combined with broadcast
  • H04H20/65—Arrangements characterised by transmission systems for broadcast
  • H04H20/71—Wireless systems
  • H04H20/72—Wireless systems of terrestrial networks
• • 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
  • H04H2201/12—Aspects of broadcast communication characterised by the type of broadcast system digital radio mondiale [DRM]
• • 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]
  • H04H2201/183—FM digital or hybrid

Definitions

• the present invention relates to an apparatus for the simultaneous broadcast of an analog and digital signal.
• the present invention relates to an apparatus as defined above which is used in the frequency band of the FM (Frequency Modulation) signal and which additionally utilizes the DRM (Digital Radio Musice) digital standard.
• FM Frequency Modulation
• DRM Digital Radio Mondiale
• FM Frequency Modulation
• This type of modulation offers some advantages over amplitude modulation (AM), in that it is less sensitive to various kinds of noise and allows for higher quality transmissions.
• AM amplitude modulation
• the band amplitude used for transmitting analog radio signals (voice) is essentially comprised within a range of about 50 kHz, which is broader than the frequency band required by the AM system but such to allow to obtain a signal transmission which is less sensitive to interference or electric discharges.
• the broader band available also allows to transmit stereo radio signals by using a so-called
• Multiplexing system which allows to manipulate both audio signals of the two stereo channels, left and right (L and R), of the program to be broadcast and to transmit them as a sum signal (L + R) and a difference signal (L - R).
• the difference signal (L - R) is then translated, through suitable known systems, above the audible band; this provides compatibility with monophonic receivers which only reproduce the sum signal, the latter being de facto equal to the monophonic content of the signal taken into account.
• the FM modulation system also supports the RDS (Radio Data System) standard, which allows to send small quantities of digital information, such as the name of the radio station, and the author and title of the track being played.
• RDS Radio Data System
• the transmission of the analog signal is often affected by noise which may alter the quality of the transmission itself; one of the most frequent types of noise is caused by propagation of the radio signal in the surrounding environment, with the signal being reflected by ground, buildings and local topographical features.
• the frequency response of the radio signal undergoes non- negligible deformations, due to destructive interference phenomena and/or phase displacements; such signal deformations may even lead to cancellation of some frequencies and, for narrow-band transmissions, to total signal loss. If the receiving apparatus is moving (e.g. on board of a moving car), this type of noise may occur together with other noise caused by the so-called "Doppler effect".
• FM analog signal broadcasting allows to transmit only one type of information, i.e. analog information.
• analog information In order to send data information, the FM system needs to use the RDS or DARC (Data Radio Channel) systems, thus requiring the use of a device capable of supporting said standard types.
• RDS or DARC Data Radio Channel
• DRM digital system
• a digital system called DRM has recently become widespread for transmitting audio and data information, which system so far uses different frequency bands from those used for FM signal broadcasting; this transmission system has allowed to overcome some of the typical drawbacks of FM transmission.
• the DRM system is an international digital transmission standard for short, medium and long waves which uses the same frequencies and the same wavelength as the corresponding current transmissions, except that, while offering an audio quality comparable to that of FM transmission, in addition to the audio signal it also allows to transmit text and data to be visualized on a display.
• the DRM transmission system however suffers from some drawbacks as well, which are related to the fact that in many countries (among which Italy) there are no frequencies available for the application of such a system to the FM transmission band, which is generally quite congested.
• the object of . the present invention is therefore to overcome the above-mentioned drawbacks.
• the object of the present invention to provide an apparatus for the simultaneous broadcast of an analog and digital signal which allows to introduce the DRM digital standard into the FM transmission frequency band.
• FM transmission which is noise-free and flexible, and which allows for sending digital data in addition to the audio signal.
• the apparatus for the simultaneous broadcast of an analog and digital signal which comprises a block or electronic card to which one, two or more analog and/or digital audio or radio signals are inputted, consisting of a plurality of blocks or units for handling and processing analog audio signals, a possible RDS (Radio Digital System) signal, and digital DRM (Digital
• Fig. 1 is a circuit block diagram of the apparatus for the simultaneous broadcast of an analog and digital signal according to the present invention.
• the apparatus for the simultaneous broadcast of an analog and digital signal designated as a whole by reference numeral 10, consists of an electronic block or card 12 which receives one, two or more signals and processes them as described below in order to obtain an output signal which is then sent to a transmitter device of a known type, which hence will not be described any further.
• the analog signals inputted to block 12 are defined by a left signal 14 and a right signal 16 (respectively designated by arrows La and Ra in Fig. 1), which are the analog audio signals of a stereophonic transmission. Said left signal 14 and right signal 16 are sent to an adder block 18, which outputs a sum signal 20.
• Sum signal 20 outputted by adder block 18 is then sent to a block or filter 22, which converts sum signal 20 into a sum signal 20' including only those components with a 15kHz frequency band, i.e. the frequency band of the monophonic sum signal.
• block or filter 22 may be overridden by the user; in such a case, the signals 20 and 20' will be the same.
• the sum signal 20' thus obtained is subsequently sent to a block 24, or decision-making block, the function of which will be described later on.
• the signal inputted to block or electronic card 12 may also be a multiplexing signal 26 (designated by arrow MPX in Fig. 1), i.e. a signal consisting of several signals sent simultaneously; as mentioned above, multiplexing allows for sending the sum signal and difference signal of the stereophonic channels as well as any RX)S and/or DARC signals.
• Multiplexing signal 26 is filtered by a filter unit 28, which lets through and outputs sum signal 30 or (A+B) signal, the single A and B signals (of the two stereophonic channels), and any RDS signal 32. All of these signals are obtained from input MPX signal 26, and are therefore related to said signal.
• the set of signals outputted by filter unit 28 defines the input of a DRM signal encoding block 34, which processes the DRM signal corresponding to the signals coming from filter 28 with a band centre frequency tendentially equal to 38 kHz.
• encoding block 34 may receive left signal 14 and right signal 16 inputted to block 12.
• Encoding block 34 may receive one or more pairs of additional analog audio signals (consisting of a monophonic signal, or a right channel signal and a left channel signal), which may even be unrelated to the signals described so far; in the preferred embodiment, said additional signals preferably consist of two pairs of left and right signals Ll, Rl and L2, R2.
• Encoding block 34 therefore provides high flexibility in choosing among the input signals thereof, and outputs a DRM type digital signal 36 which is sent to an additional adder block 38.
• the sum signal or (A+B) signal 30 may alternatively be sent to the decision-making block 24, as shown diagrammatically in Fig. 1.
• Decision-making block 24 allows to choose which signal between sum signal 20', coming from filter 22, and (A+B) signal 30, coming from filter block 30, will define the input sent to additional adder block 38 on the basis of publishing, non-technical choices.
• RDS signal 32 possibly outputted by filter unit 28 is sent to a possible additional decision- making block 40.
• RDS signal 42 inputted to block or electronic card 12 from a traditional RDS signal source, is sent to a filter unit 44 adapted to let through only the components of the RDS signal itself, i.e. an RDS signal 42'.
• RDS signal 42 has already been filtered appropriately, block or filter 44 may be overridden by the user; in such a case, signals 42 and 42' will be the same.
• RDS signal 42' outputted by filter unit 44 is sent, just like any RDS signal 32, to additional decision-making block 40.
• additional adder block 38 receives the above-defined
• Multiplexing signal 46 outputted by block or electronic card 12 is defined, as schematized in diagram 48, by an analog sum signal (A+B), a digital DRM signal and a possible RDS
• said multiplexing signal is then sent to a known conventional transmission device or apparatus.
• analog receivers are equipped with a filter which is capable of removing audio signal
• Stereophonic receivers detect the absence of the 19kHz pilot tone indicating stereo broadcasting, and use a filter which is capable of removing audio signal components at frequencies higher than 15 kHz, while letting through the typical frequency bands of RDS and DARC signals.
• DRM signal 36 is not therefore recognized by traditional analog receivers which, as aforementioned, will only receive the monophonic sum signal (A+B) and any information sent by means of an RDS or DARC signal.
• the apparatus according to the invention may also comprise, in addition to encoding block 34, a shift block adapted to change the band centre frequency of the DRM signal from 12 kHz, or from the band centre frequency of the generated DRM signal, to 38 kHz.
• a shift block adapted to change the band centre frequency of the DRM signal from 12 kHz, or from the band centre frequency of the generated DRM signal, to 38 kHz.
• a further advantage is that the apparatus according to the invention allows to adopt the DRM digital transmission standard within the FM transmission band without requiring any modifications to or replacements of the receiving and/or transmitting apparatuses currently in use, said receiving apparatuses remaining capable of receiving FM transmissions.
• a further advantage is that the apparatus according to the invention ensures more noise- resistant FM transmission and allows digital data to be transmitted along with the audio signal; furthermore, the apparatus is made flexible by the possibility of receiving radio signals of different types from different sources.
• the apparatus according to the invention may be advantageously equipped with a detector of remote control signals which, whether said remote control signals are sent separately to the same apparatus by means of another communication line or are contained in that portion of the signal 26 which is normally reserved for the difference of signal (A-B), will allow the apparatus to be controlled remotely for the purpose of including into MPX out signal 46 components of the analog and/or digital signal coming from different inputs of the same apparatus on a day and/or time basis, while also changing the composition and bit rate of the digital signal.
• This will provide, for example, easy and low-cost broadcasting of local programs within the context of a national program, only on certain days and/or within certain time intervals.
• block or filter 44 can be overridden by the user; in this case, signals 42 and 42' will be the same.
• RDS signal 42' outputted by filter unit 44 is sent, just like any RDS signal 32, to additional decision-making block 40.
• the RDS signal outputted by additional decision-making block 40, if present, is inputted to additional adder block 38.
• additional adder block 38 also receives the above-defined DRM signal 36 and the sum signal outputted by decision-making block 24; said signals are added together, thus outputting a multiplexing signal 46 (designated MPX out in the diagram).
• Multiplexing signal 46 outputted by block or electronic card 12 is defined, as schematized in diagram 48, by an analog sum signal (A+B), a digital DRM signal and a possible RDS signal; said multiplexing signal is then sent to a known conventional transmission device or apparatus.
• the sum signal (A+B) and any FM transmission RDS signal are received unchanged by both monophonic and stereophonic analog receivers.
• analog receivers are equipped with a filter which is capable of removing audio signal components at frequencies higher than 15 kHz, while letting through the typical frequency bands of RDS and DARC signals.
• Stereophonic receivers detect the absence of the 19kHz pilot tone indicating stereo broadcasting, and use a filter which is capable of removing audio signal components at frequencies higher than 15 kHz, while letting through the typical frequency bands of RDS and DARC signals.
• DRM signal 36 is not therefore recognized by traditional analog receivers which, as aforementioned, will only receive the monophonic sum signal (A+B) and any information sent by means of an RDS or DARC signal.
• the apparatus according to the invention may also comprise, in addition to encoding block 34, a shift block adapted to change the band centre frequency of the DRM signal from 12 kHz, or from the band centre frequency of the generated DRM signal, to 38 kHz.
• a shift block adapted to change the band centre frequency of the DRM signal from 12 kHz, or from the band centre frequency of the generated DRM signal, to 38 kHz.
• a further advantage is that the apparatus according to the invention allows to adopt the DRM digital transmission standard within the FM transmission band without requiring any modifications to or replacements of the receiving and/or transmitting apparatuses currently in use, said receiving apparatuses remaining capable of receiving FM transmissions.
• a further advantage is that the apparatus according to the invention ensures more noise- resistant FM transmission and allows digital data to be transmitted along with the audio signal; furthermore, the apparatus is made flexible by the possibility of receiving radio signals of different types from different sources.
• the apparatus according to the invention may be advantageously equipped with a detector of remote control signals which, whether said remote control signals are sent separately to the same apparatus by means of another communication line or are contained in that portion of the signal 26 which is normally reserved for the difference of signal (A-B), will allow the apparatus to be controlled remotely for the purpose of including into MPX out signal 46 components of the analog and/or digital signal coming from different inputs of the same apparatus on a day and/or time basis, while also changing the composition and bit rate of the digital signal.
• This will provide, for example, easy and low-cost broadcasting of local programs within the context of a national program, only on certain days and/or within certain time intervals.

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• Engineering & Computer Science (AREA)
• Signal Processing (AREA)
• Circuits Of Receivers In General (AREA)
• Stereo-Broadcasting Methods (AREA)
• Stabilization Of Oscillater, Synchronisation, Frequency Synthesizers (AREA)

Applications Claiming Priority (2)

Publications (1)

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• 2007
  • 2007-05-22 IT ITMI20071025 patent/ITMI20071025A1/it unknown
• 2008
  • 2008-05-20 EP EP08750987A patent/EP2158706A2/de not_active Withdrawn
  • 2008-05-20 WO PCT/IB2008/001254 patent/WO2008142530A2/en active Application Filing

Non-Patent Citations (1)

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