A two-module digital television decoder
The object of the invention is a two-module digital television decoder, designed for reception of television signals broadcast by different operators.
The typical set-top boxes commonly used today comprise two main modules: a 'Front-End', which comprises signal receiving means and the 'Back-End', which comprises signal decoding and processing means.
Due to a large number of television signal broadcasters and different broadcasting methods (especially, methods related to coding), the decoders supplied to users are not universal from their point of view. A decoder adapted to reception of one broadcaster's signal, usually cannot process signals of other broadcasters.
In such a situation, a user has a limited choice of decoders to use, which is often limited to a single model offered by a specific television operator.
However, such a situation is not satisfactory for all users. Some beginners do not take full advantage of all decoder features so they could use a less advanced and a cheaper model. Others need full-featured decoders e.g. having a hard disk drive, which are usually not supplied by their television operator.
Moreover, the producers design decoders as ordered by television operators. The specifications given by operators differ, according to specific needs of each operator. Therefore, each new ordered model of a decoder differs at least in details from previous models. This leads to high costs of production and a high price to be paid by the end user.
The differences between decoders, offered by various TV operators, involve mainly signal decoding procedures, which are executed by a Conditional Access (CA) unit.
A typical decoder structure, based on standard components, is presented in the international patent application WO 0217638.
The European patent application EP 0917355 discloses a method for transmission of MPEG streams in a single household television network, where a separate device is used for receiving an MPEG signal for further distribution. However, that device does not comprise a conditional access means.
In the international patent application WO 0156297 there is disclosed a system of two decoders, where one is a primary (master) and the other is a secondary (slave) decoder. However, the master decoder comprises also the features of the slave decoder, for example displaying video signal, which makes it a fully operational, standard decoder, but an expensive one. The presented solution is economic only for the users who use several television receivers. The master decoder is far more expensive than the slave decoder, which is why it is not preferred to use it as the only decoder in a household.
The US 6,040,851 patent discloses a small- format subsystem for control of broadband communication. It discloses a two-module decoder comprising one operator- dependent module and another operator-independent module, where the operator- dependent module is integrated into a very small format, e.g. a PCMCIA-type card. The connection between the modules is of a plug-socket type. Such a solution has several drawbacks. First, the operator-dependent module receives signals via the operator- independent module, which must comprise a signal input socket. Moreover, the plug- socket connection allows neither a wireless connection between the modules nor a wire connection; therefore, the device must be placed near an antenna socket.
According to the present invention, in a two-module digital television decoder, comprising two electronic circuit modules communicating with each other, from which the first is an operator-dependent module for receiving and descrambling a television signal, the module comprising input means for receiving at least one of a satellite, terrestrial or cable digital television signal, the means comprising at least one tuner and at least one demodulator, a conditional access means, comprising a card reader and a descrambler, which descrambles the signal using the key read from a card, and the second module is an operator-independent module and comprises means for processing the descrambled television signal received from the first module, comprising a processor for system control and processing audio, video and data, and an audio/video
converter for converting the received signal to a television receiver format, it is the object of the invention that the operator-dependent module is a modem, and it additionally comprises a demultiplexer for control of data flow, a bi-directional transmission means for providing a return channel functionality and a communication interface between the modem and the operator-independent module, where all components of the modem are bi-directionally connected to the demultiplexer, and the independent module is a universal decoder and it additionally comprises a memory block and a data transmission interface between the modem and the universal decoder, and all components of the universal decoder are bi-directionally connected to the processor, and the modem interface and the universal decoder interface are connected via a user-defined connection being controlled by a transmission protocol.
Preferably, the modem may be configured in such a way that the demultiplexer is a demultiplexing processor, the return channel component comprises a return channel interface and a data flow controller and the modem interface comprises a protocol controller and a transceiver.
Preferably, the modem may comprise several tuners and demodulators, each tuner-demodulator pair for receiving an individual satellite, terrestrial or cable television signal, and the back panel has separate antenna sockets for the separate signals.
The modem and the universal decoder can be connected via a common link that can be either wire or wireless link.
In case of a wire link it may be a twisted-pair with RJ45 terminals.
In case of a wireless connection, the modem and the universal decoder have built-in antennas or sockets for connection of external antennas.
The modem, in one of the embodiments, can comprise an internal power supply, which enables modem connection to the mains power supply, or may be powered with direct current from an external power supply. There is also possible an embodiment, where the modem has its own accumulators.
The universal decoder, in one of the embodiments according to the invention, can comprise an interface of an extended functionality, equivalent to the interface of the modem already described. The processor may be a digital audio/video signal processor.
The memory block of the universal decoder may comprise a RAM memory as an operational memory and also a ROM, a Flash and or an EEPROM memory as nonvolatile memories for storing software.
The universal decoder may constitute a separate device as well as be a component of another device, for example a personal computer, a DVD player, a TN set or a phone.
In another embodiment, the memory block of the universal decoder can be extended with a hard disk drive.
Moreover, the decoder can comprise additional Smartcard reader or its own return channel interface, for example using a PSTN modem.
The invention has several advantages. The separate modules can be connected via various means, not only by a plug-socket connection.
The structure of the two modules is such that the operator-dependent module does not receive a television signal via the independent module.
The system also allows a wireless connection between the operator-dependent and operator-independent modules, which allows situating the independent module in an arbitrary place.
According to the disclosed embodiments, it is also possible to use any power supply, including the AC mains, a DC voltage form an external power supply or built-in accumulators.
The disclosed two-module digital television decoder has many advantages, both from broadcasters and customers points of view and allows reducing development and production cost of a decoder. The cost of the universal decoder module, is lower, because it can be used with different modem modules. Moreover, the user may receive only the modem module from the operator, and choose the universal decoder module which best suits his needs.
The object of the invention is presented in exemplary embodiments explained in a drawing, where Fig. 1 presents a general structure of the decoder according to the invention. Fig. 2 A and fig. 2B show block diagrams of two embodiments of the modem. Their corresponding back panels have been presented in fig. 3A and fig. 3B respectively. Fig. 4A and fig. 4B show block diagrams of two embodiments of the universal decoder. Their corresponding back panels have been presented in fig. 5A and fig. 5B respectively. Fig. 6 presents a connection between the modem and the universal decoder by means of a wire link and fig. 7 presents a connection between the modem and several universal decoders by a wireless link.
A general structure of the two-module digital television decoder according to the invention is shown in fig. 1. It comprises two connectable electronic circuit modules, from which the first module is an operator-dependent modem module 100, used for receiving and descrambling a television signal by conditional access means and the second module is an operator-independent universal decoder module 150 , used for processing the descrambled television signal received from the modem module 100. Both modules comprise components for connecting with each other.
The modem module 100 comprises input means 101, signal filtering and flow control means in a form of a demultiplexer 102. a bi-directional transmission means 103 providing a return channel functionality, conditional access means 104, comprising a card reader and a descrambler, which descrambles the signal using the key read from a card, and an interface 105 for transmission of data and control commands between the modem 100 and the universal decoder 150.
All the components of the modem 100 are connected bi-directionally with the demultiplexer 102.
The input means J Ol. of the modem 100 allow receiving at least one satellite, terrestrial or cable television signal and comprise at least one tuner and at least one demodulator.
The universal decoder module 150 comprises an interface 151 for transmission of data and control commands between the modem 100 and the universal decoder 150. a processor for system control and processing audio, video and data 152. a memory block 153 and an audio/video converter 154 for converting the received signal to television receiver format.
All the components of the universal decoder 150 are connected bi-directionally with the processor 152.
The modem 100 interface 105 and the universal decoder 150 interface 105 are connected bi-directionally. The data flow is controlled by a transmission protocol SP, for example a TCP/IP protocol for control of data flow over an Ethernet network.
Fig. 2A shows a detailed structure of a first exemplary embodiment 100 A of the modem module. The input means 101A comprise one tuner and one demodulator. The demultiplexer 102 A can be an STMicroelectronics ST20 demultiplexing processor. The bi-directional transmission means 103 providing a return channel functionality comprise
an interface 1031 for managing the transmission via a given transmission medium and a data flow controller 103C. which, among other functionality, divides data into packets. The interface 105 comprises a protocol controller 105P and a transceiver 105T.
Fig. 2B shows a detailed structure of a second exemplary embodiment 100B of the modem module. It is an extended version of the modem shown in fig. 2. The modem 100B input means 101B comprise separate tuners and demodulators, each pair for receiving an individual satellite, terrestrial and/or cable television signal. In such a configuration, the back panel has separate antenna sockets for the individual signals.
Scrambled streams are input to the processor 102B. The processor 102B outputs a descrambled stream to the interface 105. The processor 102B can manage simultaneous transmission and descrambling of several streams received by the input means 101.
The modem 100 and the universal decoder 150 can be connected via a common link that can be either wire or wireless link.
In case of a wire link it may be a twisted-pair with RJ45 terminals.
In case of a wireless connection, the modem 100 and the universal decoder 150 have built-in antennas or sockets for connection of external antennas.
The modem 100, in one of the embodiments, can comprise an internal power supply, which enables modem connection to the mains power supply, or may be powered with direct current from an external power supply. There is also possible an embodiment, where the modem 100 has its own accumulators.
Exemplary back panels of modems 100 A and 100B shown in fig. 2 A and fig. 2B are presented in fig. 3 A and fig. 3B respectively.
The back panel of modem 100 A shown in fig. 3 A comprises the following input or output ports:
At least one digital television signal input;
An optional input/output return channel port - for connection for example to a cable television network or a PSTN line; A Smartcard reader;
2004/023811
Ports of the interface 105 between the modem 100 and the universal decoder 150 - for example, a twisted-pair with RJ45 terminals; in case of a wireless connection, the modem 100 and the universal decoder 150 have built-in antennas or sockets for connection of external antennas.
Power supply ports - The modem 100 may be supplied with power from mains (AC) (in case of a built-in AC/DC converter) or may be supplied with a direct current (DC) from an external power supply. There is also possible an embodiment where the modem has its own accumulators.
The back panel of the modem 100B shown in Fig. 2B, in comparison to the panel of the modem 100A shown in fig. 2A, comprises additional television signal inputs. It allows reception of several television signals, for example signals of satellite and of cable television. There may be more than two of such inputs.
Fig. 4A and fig. 4B show detailed structures of two exemplary embodiments of the universal decoder 150. having several components in common.
The decoder 150A has the interface J_5_l, comprising a protocol controller 151P and a transceiver 151T. The processor 152A can be for example an STMicroelectronics ST5514 processor.
The memory block 153A of the universal decoder 150A may comprise a RAM memory as an operational memory, and also a ROM memory, a Flash, an EEPROM, a CD, a DVD, as non- volatile memories for storing software.
The universal decoder 150A may constitute a separate device as well as be a component of another device, for example a personal computer, a DVD player, a TV set or a phone.
In the second embodiment 150B of the decoder shown in Fig. 5, the memory block 153B is extended with a hard disk drive (HDD). Moreover, the decoder 150B can comprise an additional Smartcard reader 156 or its own return channel interface 155, which may be for example a PSTN modem.
Exemplary back panels of universal decoders 150A and 150B shown in fig. 4A and fig. 4B are presented in Fig. 5A and fig. 5B respectively.
According to the embodiment presented in Fig. 4A the universal decoder 150 A may comprise:
Ports of the interface 151 between the modem 100 and the universal decoder 150 - for example, a twisted-pair with RJ45 terminals; in case of a wireless connection, the modem 100 and the universal decoder 150 have built-in antennas or sockets for connection of external antennas.
An audio/video port in one of the common standards, for example a SCART port.
Power supply ports - The decoder 150 may be supplied with power from mains (AC) (in case of a built-in AC/DC converter) or may be supplied with a direct current (DC) from an external power supply. There is also possible an embodiment where the modem has its own accumulators.
According to the embodiment presented in Fig. 5A, the universal decoder 150B may further comprise:
An optional return channel port - for connection for example to a cable TV network or a PSTN line; - An optional Smartcard reader;
The disclosed decoders 150 may comprise additional ports, which presence depends on additional decoder features, when the decoder is a component of another device (for example, a DVD player).
The output signal ports are present only in universal decoders that are external devices. Obviously, they are redundant in built-in decoders, for example those in TV- sets or telephones.
Fig. 6 presents the simplest connection between the modem and the universal decoder via a wire link. The modem 100 is placed near a cable television socket and receives a TV signal. The signal is then descrambled and next sent via the interface 105 and the wire link to the interface 151 of the universal decoder 150. which is placed near a TV-set that displays a chosen video signal.
Fig. 7 presents a wireless connection, for example through an IEEE 802.11 link, between the modem 100 and three universal decoders 150. The modem 100 sends a descrambled television signal to the universal decoders 150: one that is connected to a TV-set, a second that is built in a TV-set and a third that constitutes a personal computer extension card.