Extension device

An antenna (8), mounted to a roof (3) of a building (1), receives digital broadcast transmissions and feeds a signal through a cable (9) to a desk stand (2). The desk stand has an amplifier and a loop antenna. A mobile telephone handset (6) capable of receiving digital broadcast transmissions also includes a loop antenna. Using inductive coupling, the signal is transmitted from the desk stand to the mobile telephone handset.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is the U.S. National Stage of International Application Number PCT/IB2004/051829 filed Sep. 22, 2004, published in English Apr. 7, 2005 under International Publication Number WO 2005/031910 A2, and applicant claims priority from Great Britain Application Number GB 0322774.1 filed Sep. 29, 2003.

FIELD OF THE INVENTION

The present invention relates to an extension device for delivering a digital broadcast to a mobile terminal.

BACKGROUND ART

Digital broadcasting networks can be used to deliver enhanced services to users having digital broadcasting receivers. Examples of digital broadcasting networks include a Digital Video Broadcasting (DVB) network, a Digital Audio Broadcasting (DAB) network, an Advanced Television Systems Committee (ATSC) network and an Integrated Service Digital Broadcasting (ISDB) network.

It is proposed to provide Internet Protocol Datacast (IPDC) services as part of a terrestrial Digital Video Broadcasting (DVB-T) system or handheld DVB (DVB-H) system. IPDC permits data to be transmitted at high transfer rates to many users simultaneously and so can be used to stream video content and transfer data files.

It is also proposed to incorporate a DVB receiver into a conventional mobile telephone handset or personal digital assistant (PDA). This has the advantage that it allows a user to download large amounts of data quickly using IPDC, data which ordinarily would take too long and be prohibitively expensive to transfer using a conventional mobile handset and conventional public land mobile networks.

Initially, provision of DVB transmitters and implementation of IPDC is unlikely to be widespread. Therefore, service coverage is likely to be limited. Therefore, it is desirable to extend service coverage wherever possible. Furthermore, even when further transmitters are installed and IPDC becomes more widely available, it is still desirable to maximise service coverage.

Service coverage is often restricted because receivers are taken indoors. Walls and other parts of a building attenuate transmitted signals. Thus, although service coverage may be adequate outdoors, it may be insufficient indoors even though the receiver has moved just a few meters. Additionally, service coverage may be impeded by other buildings.

Extension sets are known. EP-A-1076376 describes an extension set for a DVB-T receiver in which the extension set and receiver are connected by a wired link. This has the disadvantage that it restricts mobility of the mobile terminal. WO-A-02089361 also describes an extension set for a DVB-T receiver in which the extension set re-emits a received signal. However, this has a drawback of being indiscriminate. Thus, a receiver may receive signals from a number of extension sets and the signals may interfere. DE-A-10123556 describes a mobile terminal holder in which the holder transmits a signal to the mobile telephone. However, the signal can be significantly attenuated during transmission.

The present invention seeks to ameliorate at least some these problems.

SUMMARY OF THE INVENTION

According to a first aspect of the present invention there is provided an extension device for delivering digital broadcasts to a mobile terminal, the device comprising means for receiving a signal carrying the digital broadcast received via an antenna; and a loop or coil configured to couple inductively with a corresponding loop or coil included in the mobile terminal so as to transmit the signal to the mobile terminal.

The device may further comprise means for amplifying the signal. The amplifying means may be powered by the mobile terminal. The amplifying means may be controlled by said mobile terminal. The amplifying means may intermittently operate under the control of the mobile terminal. This can have the advantage of reducing power consumption and minimising transmission of signals when not required.

The device may comprise means for detecting the mobile terminal and means for controlling operation of said amplifying means in dependence upon the position of the mobile terminal. The detecting device may comprise a switch to determine whether said mobile terminal is attached to the extension device. The term “attached” means placed in, on or against. The detecting device may comprise means for sensing whether the mobile terminal is located within a predetermined distance of said extension device. The controlling means may cause the amplifying means to reduce gain or to be by-passed when the mobile terminal is in a given position, such as when the mobile is attached or is within the predetermined range. This can help to limit the power delivered to the mobile terminal, which can help to prevent saturation of amplifiers and/or other circuits in the mobile terminal.

The device may further comprise an antenna for receiving an amplified signal from the amplifying means and radiatively transmitting the amplified signal to the mobile terminal, wherein said controlling means causes the signal to be routed to the loop or coil when the mobile terminal is in a given position, such as when the mobile is attached or is within the predetermined range and to be routed to the amplifying means when not. This can help to deliver the signal in a suitable way.

The extension device may comprise means for filtering the signal from at least one other signal.

The extension device may comprise means for receiving power from an external source and means for delivering power to the mobile terminal to permit recharging of a rechargeable battery included in the mobile terminal.

The extension device may be adapted to be placed on a piece of furniture, such as desk or table. For example, the extension device may be configured as a desk stand. Thus, the extension device can be put at a level and/or in a place where the mobile terminal is likely to be used or stored.

The loop or coil may be a loop and the loop may be arranged substantially around a perimeter of a face of the device. The loop or coil may have an area of between 10 and 50 cm2.

The device may further comprise an antenna mounted on a roof or to an externally facing side of an external wall of a building.

According to a second aspect of the present invention there is provided apparatus for receiving a time-sliced digital broadcast comprising a mobile terminal including a loop or coil and an extension device comprising means for receiving a signal carrying the digital broadcast received via an antenna and a loop or coil configured to couple inductively with the corresponding loop or coil included in a mobile terminal so as to transmit the signal to the mobile terminal.

The mobile terminal may cause the amplifying means to operate when reception of a time slice is expected.

According to a third aspect of the present invention there is also provided a method of delivering a digital broadcast to a mobile terminal, the method comprising receiving a signal carrying a digital broadcast via an antenna and providing said signal to a loop or coil configured to couple inductively with a corresponding loop or coil included in the mobile terminal so as to transmit the signal to the mobile terminal.

DETAILED DESCRIPTION OF THE INVENTION

Referring toFIG. 1, an environment1in which an extension device2,102,202,302,402,502,602,702according to the present invention can be used is shown. In this example, the environment1is a two-story house having a roof3, external walls41,42, internal walls (not shown) and floors (not shown). However, the environment may be any domestic building of any design and having any number of floors, or a part of a domestic building, such as a room, flat or apartment. The environment may be any sort of commercial or industrial premises, such as an office or factory. The environment may be located underground.

For the purposes of illustration, a part of an external wall41is shown removed to reveal the inside of the house1. Inside the house1, the extension device2,102,202,302,402,502,602,702is conveniently placed on a piece of furniture5, such as a desk or table, and is used to deliver a digital broadcast to a mobile terminal6. A signal7carrying the digital broadcast is received via an antenna8, which is preferably mounted on the roof3. Alternatively, the antenna8may be mounted to an external wall41,42. The antenna8is connected to the extension device2,102,202,302,402,502,602,702by a cable9. Preferably, the cable is in the form of a co-axial cable. However, the signal may be converted into an optical signal which may be transmitted through fibre or through air.

Referring toFIG. 2, the mobile terminal6is in one embodiment of the invention in the form of a mobile communications device such as a mobile telephone handset for use in both a communications network (not shown) and a digital broadcasting network (not shown). Preferably, the communications network is a second generation (2G) communications network, such as a GSM network. However, the communications network may be any mobile phone network, for example a 3G network, such as UMTS.

The mobile telephone handset6comprises an antenna101for sending and receiving signals via the communications network and receiving signals from the broadcasting network, transceiver circuit11for, inter alia, modulating/de-modulating and amplifying signals from the communications network (not shown), processor12for, inter alia, coding/decoding signals, baseband processing and other signal processing and managing operation of the mobile terminal6, keypad13for providing user input, display14for providing output, storage15, a smart card reader16, smart card17received in the smart card reader16, a coder/decoder (codec)18, a speaker19with corresponding amplifier20and a microphone21with a corresponding pre-amplifier22, a connector23for a hands free kit (not shown), a battery24, a switch25and a connector26for a mains supply (not shown) or a mains-powered supply (not shown). The processor12can be used to open and close switch25. The processor can also be used to control the extension device2,102,202,302,402,502,602,702preferably via connector26.

The mobile terminal6also comprises means27for receiving a signal using inductive coupling, an optional second antenna102and a receiver circuit28for, inter alia, de-modulating and amplifying signals from the digital broadcasting network (not shown) received via antenna102or inductive coupling receiving means27. The inductive coupling receiving means27takes the form of a loop or a coil. The loop27may run around a perimeter of a face of the device6and have an area of the order between 0.1 to 10 cm2. Preferably, the loop27has an area of between 10 and 50 cm2. A coil comprising a number of turns may be used.

The mobile terminal6also comprises a Bluetooth™ transceiver29for establishing a personal area network (PAN) with one or more other Bluetooth™ transceivers, such as Bluetooth™ transceiver649(FIG. 10), thereby allowing the mobile terminal6to exchange signals with other Bluetooth-enabled devices, such as extension device602(FIG. 10).

The receiver28is in the form of an Internet Protocol Datacasting (IPDC) receiver. Preferably, the digital broadcasting network is a terrestrial Digital Video Broadcasting (DVB-T) network or a handheld DVB (DVB-H) network. However, other digital broadcasting networks may be used such as a Digital Audio Broadcasting (DAB) network, an Advanced Television Systems Committee (ATSC) network or an Integrated Service Digital Broadcasting (ISDB) network. To receive signals from the digital broadcasting network (not shown), the antenna102and receiver circuit28are adapted to receive ultra high frequency (UHF) signals, for example lying in the range 470 to 862 MHz.

It will be appreciated that loop27may be used as a receiving antenna instead of antenna102.

As will be explained in more detail later, the inductive coupling means27can be used to receive a signal carrying a digital broadcast from the digital broadcasting network (not shown) received via antenna8(FIG. 1) and delivered by an extension device2,102,202,302,402,502,602,702(FIG. 1).

First Embodiment

Referring toFIG. 3, a first embodiment of an extension device2according to the present invention is shown.

The extension device2comprises means30for receiving a signal received via an antenna which is in the form of a connector, also referred to as a “terminal”, for receiving a corresponding connector (not shown) at the end of the cable9(FIG. 1) and means31for transmitting the signal to the mobile terminal6by inductive coupling which is in the form of loop. The loop31may have an area of the order between 0.1 to 10 cm2. Preferably, the loop31has an area of between 10 and 50 cm2. Preferably, the loop31is impedance matched to the cable9(FIG. 1) connected to the connector30.

In use, the mobile terminal6is preferably located in the near field of the loop31, in other words the mobile terminal is placed no more than a few centimetres away from the loop31and the loops27,31are inductively coupled. The mobile terminal6and the extension device2may be separated by greater distances, but this leads to significant signal attenuation.

Referring toFIG. 4, the extension device2is preferably arranged as a cradle for receiving mobile terminal6. The extension device2is preferably arranged such that when the mobile terminal6is received in or placed on the extension device2, the loop27of the mobile terminal6is placed against or within a few millimetres of the loop31of the extension device2. Preferably, planes of the loops27,31are substantially parallel. Preferably, the loops27,31are co-axial.

Referring also toFIGS. 1 and 2, a signal7is received by the antenna8, fed through cable9and supplied to the extension device2via the connector30. The signal7is fed through the loop31.

A corresponding signal is induced in the loop27of the mobile terminal6and is passed into the receiving circuit28(FIG. 2) for amplifying and demodulating and thereafter baseband processing, channel decoding, de-multiplexing and further processing by processor12(FIG. 2).

In this way, the mobile terminal6, which might otherwise not be able to receive the signal7inside the house1, can now do so with the help of the extension device2.

In this embodiment of the present invention, amplifying means is not used because antenna8(FIG. 1) provides a gain of up to 10 dB and even up to 20 dB. A signal booster (not shown), which is also known as a “mast amplifier”, may also be provided.

Second Embodiment

Referring toFIG. 5, a second embodiment of an extension device102according to the present invention is shown.

The extension device102comprises means130for receiving a signal received via an antenna which is in the form of a connector, also referred to as a “terminal”, for receiving a corresponding connector (not shown) at the end of the cable9(FIG. 1), means132for amplifying the signal in the form of a wideband UHF low noise amplifier (LNA) and means131for transmitting the amplified signal to the mobile terminal6by inductive coupling which is in the form of loop. The loop131may have an area of the order between 0.1 to 10 cm2. Preferably, the loop131has an area of between 10 and 50 cm2. A battery133powers the LNA132. Preferably, the LNA132is impedance matched to the cable9(FIG. 1) connected to the connector130and also impedance matched to the loop131.

Preferably, the extension device102is arranged as a cradle for receiving mobile terminal6as shown inFIG. 4.

In use, the extension device102operates substantially similar to extension device2described earlier. However, the signal7is amplified by the LNA132so as to compensate for signal attenuation during transmission of the signal to the mobile terminal6(FIG. 1). The amplified signal is fed through the loop131.

In this way, the mobile terminal6, which might otherwise not be able to receive the signal7inside the house1, can now do so with the help of the extension device102.

To determine whether the extension device102will help and/or to determine a minimum gain of the amplifier132, a gain necessary to provide adequate indoor reception may be found by routine experiment. For example, signal strength at the antenna8may be measured or estimated for a typical location, such a suburb of a city. Gain of the antenna8may be measured or estimated. For example, a UHF antenna may be estimated as providing a gain of up to 10 dB and even up to 20 dB. Attenuation due to signal transmission by inductive coupling may be measured or estimated. Other sources of gain and loss may be taken into account. Thus, a gain (or loss) can be determined.

Third Embodiment

Referring toFIG. 6, a third embodiment of an extension device202according to the present invention is shown.

The extension device202comprises means230for receiving a signal received via an antenna, which is in the form of a connector for receiving a corresponding connector (not shown) at the end of the cable9(FIG. 1), means234for power amplifying the signal in the form of a wideband UHF power amplifier and means231for transmitting the amplified signal to the mobile terminal by inductive coupling in the form of loop. Preferably, the power amplifier234is impedance matched to the cable9(FIG. 1) connected to the connector230and also impedance matched to the loop231. Instead of being connected to the loop231, the power amplifier234may be connected to an antenna (not shown), such as a radiating antenna. Furthermore, a switching means (not shown) may be provided to switch the output of the connector230either to the loop231or to power amplifier234for transmission via the radiating antenna.

The extension device202also comprises means235for receiving power from an external power source (not shown). Alternatively or additionally, the extension device202may comprise a battery. Power lines are shown as short-dashed lines.

The extension device202may also comprise means236for controlling operation of the amplifying means for example in the form of a microcontroller and means237for detecting whether the mobile terminal6is attached to or located within a predetermined distance of the extension device202, such as a switch or electrical contact. Control and/or signalling lines are shown as long-dashed lines. The controlling means236may disconnect power or reduce gain of the power amplifier, if the detecting means237senses that the mobile terminal6is attached to or is close to the extension device202, thereby limiting the power delivered to the mobile terminal6and preventing saturation of amplifiers and/or other circuits within the mobile terminal6.

Preferably, the extension device202is arranged as a cradle for receiving mobile terminal6as shown inFIG. 4.

In use, the extension device202operates substantially similar to extension device102described earlier.

However, the extension device202may additionally limit power of the power amplifier234if the mobile terminal6is attached to or brought close to the extension device202. For example, the extension device202may provide a cradle (FIG. 4) or holder and the mobile terminal6is placed on or in the cradle or holder, thus closing the switch237.

An advantage of using a power amplifier234is that a higher power can be delivered. For example, transmitted signal power can lie in a range between 0.1 mW and 10 mW. Alternatively, transmitted signal powers of 10 mW or greater can be used.

Fourth Embodiment

Referring toFIG. 7, a fourth embodiment of an extension device302according to the present invention is shown.

The extension device302comprises means330for receiving a signal received via an antenna, which is in the form of a connector for receiving a corresponding connector (not shown) at the end of the cable9(FIG. 1), means332for amplifying the signal in the form of a wideband UHF low noise amplifier (LNA) and means331for transmitting the amplified signal to the mobile terminal by inductive coupling, which is in the form of loop. Preferably, the LNA332is impedance matched to the cable9(FIG. 1) connected to the connector330and also impedance matched to the loop331.

The extension device302also comprises means339for receiving power from an external power source, such as e.g. mobile terminal6. The power receiving means339is in one embodiment of the invention in the form of a power supply connector and is configured to be attached to the power supply connector26of the mobile terminal6(FIG. 2). The extension device302also comprises means338for controlling power supply to the LNA332, for example in the form of a switch. Power lines are shown as short dashed lines and control/signalling lines are shown as long dashed lines.

Referring also toFIG. 4, the extension device302is preferably arranged as a cradle for receiving mobile terminal6. When the mobile terminal6is placed in the cradle302, the power supply connectors26,339are connected, thereby enabling processor12(FIG. 2) to control supply of power to the extension device using switch25(FIG. 2) and/or switch338.

In use, the extension device302operates substantially similar to extension device102described earlier. However, the extension device302may be selectively powered by the mobile terminal6.

This is particularly useful for receiving Internet Protocol Datacasting (IPDC) service. To reduce power consumption of mobile DVB receivers, such as mobile terminal6, IPDC services may be transmitted in bursts preferably using the entire channel bandwidth or most of it. This is known as “time slicing”. Time slicing parameters such as burst transmission time, burst duration and transmission frequency (or channel) are signalled to the mobile terminal6. With this information, the mobile DVB receiver can be switched off between bursts.

Selectively controlling power to the extension device302is also useful when generally receiving DVB transmissions (which may or may not be transmitted in time-sliced bursts). The mobile DVB receiver can be switched on to receive content, such a video stream or data file, transmitted at a known time and thereafter switched off. The content can be stored in storage15(FIG. 2) and consumed or used at a later time.

Thus, when the mobile terminal6is connected to the extension device302, the mobile terminal6can selectively supply power to the extension device302to enable reception of a burst and/or a content transmission slot.

Fifth Embodiment

Referring toFIG. 8, a fifth embodiment of an extension device402according to the present invention is shown.

The extension device402is similar to the extension device302described earlier differing in that it can power itself using a power source other than mobile terminal6and also in that it can provide a battery charging facility to the mobile terminal6.

The extension device402comprises means430for receiving a signal received via an antenna, which is in the form of a connector for receiving a corresponding connector (not shown) at the end of the cable9(FIG. 1), means432for amplifying the signal in the form of a wideband UHF low noise amplifier (LNA) and means431for transmitting the amplified signal to the mobile terminal by inductive coupling in the form of loop. Preferably, the LNA432is impedance matched to the cable9(FIG. 1) connected to the connector430and also impedance matched to the loop431.

The extension device402also comprises means439for delivering power to/from a mobile terminal6. The power delivering means439is in one embodiment of the invention in the form of a power supply connector and is configured to be releasably attached or connected to the power supply connector26(FIG. 2). The extension device402also comprises means438for controlling power supply to the LNA432for example in the form of a switch. Power lines are shown as short dashed lines and control/signal lines are shown as long dashed lines.

The extension device402further comprises means440for receiving power from an external power source in the form of a power supply connector, means441for charging a rechargeable battery in the form of a circuit including a transformer (not shown), rectifier (not shown) and controller (not shown), means442for storing power in the form of a rechargeable battery and means443for controlling power in the form of a switch. The charging means441may be used to charge the battery442in the extension device442and/or the battery24(FIG. 2) in the mobile terminal6. When the extension device402is connected to an external power source (not shown), charging means441charges battery442until it is full.

Preferably, the extension device402is arranged as a cradle for receiving mobile terminal6as shown inFIG. 4.

In use, the extension device402operates substantially similar to extension device302. However, power need not be supplied by the mobile terminal6. Nevertheless, power supply to the LNA432may still be controlled by the mobile terminal6through switch438.

If the extension device402is connected to an external power source (not shown), the LNA432can be powered by the external source (not shown), preferably under the control of the processor12(FIG. 2) using switch438. If the LNA432is not being powered, then the power can be used to charge battery24(FIG. 2).

If the extension device402is disconnected from the external power source (not shown), the LNA432can be powered by battery442, preferably under the control of the processor12(FIG. 2).

If the extension device402is disconnected from the external power source (not shown) and there is insufficient power stored in battery442, the LNA432can be powered by battery24(FIG. 2).

Sixth Embodiment

Referring toFIG. 9, a sixth embodiment of an extension device502according to the present invention is shown.

The extension device502is similar to the extension device402described earlier differing in that it can transmit a more powerful signal, which can be controlled according to whether the device502and the mobile terminal6are connected.

The extension device530comprises means530for receiving a signal received via an antenna in the form of a connector for receiving a corresponding connector (not shown) at the end of the cable9(FIG. 1), optional first means532for amplifying the signal in the form of a wideband UHF low noise amplifier (LNA), a second means534for amplifying the signal in the form of a wideband power amplifier, means531for transmitting the amplified signal to the mobile terminal by inductive coupling in the form of loop and means544for switching the output of the LNA532either directly to the loop531or via the power amplifier534. Instead of being connected to the loop531, the power amplifier534may be connected to a radiating antenna (not shown). The extension device502further comprises means537for detecting whether the mobile terminal6is attached to or located within a predetermined distance of the extension device502and for controlling switch544. The detecting means537is preferably in the form of a switch or electrical contact. Thus, if the detecting means537senses that the mobile terminal6is attached to the extension device502, then it causes the switch544to switch the output of the LNA532directly to the loop531so as to by-pass the power amplifier534. This limits the power delivered to the mobile terminal6and so helps to prevent saturation of amplifiers and/or other circuits.

The extension device502also comprises means539for delivering power to/from a mobile terminal6. The power delivering means539is in one embodiment of the invention in the form of a power supply connector and is configured to be attached to the power supply connector26(FIG. 2). The extension device502also comprises means538for controlling power supply to the amplifiers532,534for example in the form of a switch. Power lines are shown as short dashed lines and control lines are shown as long dashed lines.

The extension device502further comprises means540for receiving power from an external power source in the form of a power supply connector, means541for charging a rechargeable battery in the form of a circuit including a transformer (not shown), rectifier (not shown) and controller (not shown), means542for storing power in the form of a rechargeable battery and means543for controlling power in the form of a switch. The charging means541may be used to charge the battery542in the extension device502and/or the battery24(FIG. 2) in the mobile terminal6, in a manner similar to that described in relation to extension device402.

Preferably, the extension device502is arranged as a cradle for receiving mobile terminal6as shown inFIG. 4.

In use, the extension device502operates substantially similar to extension device402. However, as explained earlier, if the mobile terminal6is connected to the extension device502, for example by being placed in the cradle and switch537is actuated, then it causes switch544to by-pass the power amplifier534, thereby limiting the power delivered to the mobile terminal6. Other arrangements may be used instead of by-passing the amplifier534. Instead, the power amplifier534may be disabled or set to unity gain.

The LNA532may be omitted. Thus, the signal may be fed directly into the loop531so as to by-pass the power amplifier534.

The LNA532and power amplifier534are preferably impedance matched to elements530,544,531to which they are connected. The LNA532is preferably impedance matched to the cable9connected to the connector530.

Seventh Embodiment

Referring toFIG. 10, a seventh embodiment of an extension device602according to the present invention is shown.

In previous embodiments, substantially all signals received by an extension device are amplified and re-transmitted. In this embodiment, a signal can be selectively amplified and re-transmitted.

The extension device602comprises means630for receiving a signal received via an antenna in the form of a connector for receiving a corresponding connector (not shown) at the end of the cable9(FIG. 1), means645for filtering a signal, preferably in the form of a tunable tracking filter, optional means632for amplifying a signal in the form of a wideband UHF low noise amplifier (LNA), means634for amplifying the signal in the form of a wideband power amplifier, means631for transmitting the amplified signal to the mobile terminal6by inductive coupling in the form of a loop and means644for switching the output of the LNA632either directly to the loop631or via the power amplifier634. Instead of being connected to the loop631, the power amplifier634may be connected to a radiating antenna (not shown). The extension device602comprises means637for detecting whether the mobile terminal6is attached to or located within a predetermined distance of the extension device602and for controlling switch644. The detecting means637is preferably in the form of a switch or electrical contact. Thus, if the detecting means637senses that the mobile terminal6is attached to the extension device602, then it causes the switch644to switch the output of the LNA632directly to the loop631(or other antenna) so as to by-pass the power amplifier634and thereby limit the power delivered to the mobile terminal6thus preventing saturation of amplifiers and/or other circuits. Power lines are shown as short dashed lines and control lines are shown as long dashed lines.

The extension device602also comprises means639for delivering power to/from a mobile terminal6. The power delivering means639is in one embodiment of the invention in the form of a power supply connector and is configured to be attached to the power supply connector26(FIG. 2). The extension device602also comprises means638for controlling power supply to the amplifiers632,634, the filter645and other units646,647,648,649, preferably in the form of a switch.

Power lines are shown as short dashed lines and control lines are shown as long dashed lines.

The extension device602further comprises means640for receiving power from an external power source in the form of a power supply connector, means641for charging a rechargeable battery in the form of a circuit including a transformer (not shown), rectifier (not shown) and controller (not shown), means642for storing power in the form of a rechargeable battery and means643for controlling power for example in the form of a switch. The charging means641may be used to charge the battery642in the extension device602and/or the battery24(FIG. 2) in the mobile terminal6, in a manner similar to that described in relation to extension device402.

The extension device may optionally comprise means646for controlling the band pass filter, e.g. in the form of a processor, means647for interfacing with a user including a number of buttons (not shown), means648for storing data, such as memory, and means649for interfacing wirelessly over a short range for example in the form a Bluetooth™ transceiver.

Preferably, the extension device602is arranged as a cradle for receiving mobile terminal6as shown inFIG. 4.

In use, the user can select a given signal, which can be referred to as a channel, via user interface647or via a mobile terminal6via Bluetooth™ transceiver29(FIG. 2). The processor646causes the tunable tracking filter to select signal7in preference to other received signals (not shown). Thereafter, the extension device602operates substantially similar to extension device502.

The signal filtering means645may be a complete UHF tuner in which signal7is converted into an intermediate frequency (IF) and re-converted back to the original frequency. The signal filtering means645may be fixed.

Eighth Embodiment

Referring toFIG. 11, an eighth embodiment of an extension device702according to the present invention is shown.

The extension device702comprises means730for receiving a signal received via an antenna in the form of a connector for receiving a corresponding connector (not shown) at the end of the cable9(FIG. 1), means745for filtering a signal, preferably in the form of a tunable tracking filter, means750for down-converting from a first frequency to an intermediate frequency and up-converting to a second frequency, optional means732for amplifying a signal in the form of a wideband UHF low noise amplifier (LNA), means734for amplifying the signal in the form of a wideband power amplifier, means731for transmitting the amplified signal to the mobile terminal6by inductive coupling in the form of loop and means744for switching the output of the LNA732either directly to the loop731or via the power amplifier734. Instead of being connected to the loop731, the power amplifier734may be connected to a radiating antenna (not shown). The extension device702comprises means737for detecting whether the mobile terminal6is attached to or located within a predetermined distance of the extension device702, such as a switch or electrical contact, and for controlling switch744. Thus, if the detecting means737senses that the mobile terminal6is attached to the extension device702, then it causes the switching means744to switch the output of the LNA732directly to the loop731so as to by-pass the power amplifier734and thereby limit the power delivered to the mobile terminal6thus preventing saturation of amplifiers and/or other circuits.

The extension device702also comprises means739for delivering power to/from a mobile terminal6. The power delivering means739is in one embodiment of the invention in the form of a power supply connector and is configured to be attached to the power supply connector26(FIG. 2). The extension device702also comprises means738for controlling power supply to the amplifiers732,734, the filter745, up/down converter750and other units746,747,748,749, in the form of a switch. Power lines are shown as short dashed lines and control lines are shown as long dashed lines.

The extension device702further comprises means740for receiving power from an external power source in the form of a power supply connector, means741for charging a rechargeable battery in the form of a circuit including a transformer (not shown), rectifier (not shown) and controller (not shown), means742for storing power in the form of a rechargeable battery and means743for controlling power for example in the form of a switch. The charging means741may be used to charge the battery742in the extension device702and/or the battery24(FIG. 2) in the mobile terminal6, in a manner similar to that described earlier.

The extension device may optionally comprise means746for controlling the band pass filter745and up/down converter750in the form of a processor, means747for interfacing with a user including a number of buttons (not shown), means748for storing data, such as memory, and means749for interfacing wirelessly over a short range for example in the form a Bluetooth™ transceiver. This allows a user to select an alternate frequency for re-transmission.

Preferably, the extension device702is arranged as a cradle for receiving mobile terminal6as shown inFIG. 4.

In use, the extension device702operates substantially similar to extension device602described earlier. However, not only is it possible to select a given frequency, but also to up or down convert to another frequency.

From reading the present disclosure, other variations and modifications will be apparent to persons skilled in the art. Such variations and modifications may involve equivalent and other features which are already known and may be used instead of or in addition to features already described herein. Furthermore, any feature used in one embodiment may be used in another embodiment.