WO2001037437A2

WO2001037437A2 - Removable wireless device

Info

Publication number: WO2001037437A2
Application number: PCT/GB2000/004339
Authority: WO
Inventors: Lionel Wolovitz; Richard J. Horan
Original assignee: Psion Connect Limited
Priority date: 1999-11-15
Filing date: 2000-11-15
Publication date: 2001-05-25
Also published as: GB0027881D0; GB2357190B; GB2357190A; GB0027867D0; GB2357189A; GB2357189B; JP2003514482A; WO2001037437A3; EP1221203A2

Abstract

A PC Card includes a slide out antenna platform on which is also mounted at least one component, such as a baseband processor, which can perform digital processes. Placing the component(s) which perform(s) digital processes next to the antenna removes the need for a flexible and expensive connection which would be required if, for example, the platform included solely HF components. When the platform partly slides out of the PC Card casing, it automatically turns the device on; sliding the platform back in automatically turns the device off. The platform can also be fully removed from the PC Card for replacement with an upgrade.

Description

Removable Wireless Device

Field of the Invention

This invention relates to a removable wireless device which can be readily inserted into and entirely removed from a computing device. The term 'wireless device' used in this specification refers to any electronic device which includes a wireless reception and/or transmission capability, irrespective of whether or not other (e.g. wire based) forms of communications capabilities are also supported. Applicable wireless formats include, without limitation, the Bluetooth and 802.11 short range radio standards.

Prior Art Description

Providing a conventional notebook computer with wireless communications capabilities can be done in several ways, including for example, the use of a GSM PC Card inserted into the PC Card bay of the notebook computer. One design constraint affecting wireless devices is that an antenna generally has to protrude significantly from the wireless device casing, since that casing is usually metal and would therefore screen incoming and outgoing radiation. Hence, an antenna formed on a PC Card also has to extend significantly from the metal casing of the PC Card when in use.

This has led to three kinds of commercially manufactured antenna designs for wireless devices: first, antennas which are permanently connected to their associated radio receiver/ transmitter hardware but are hinged and can fold out of a casing for use. An example of this would be a PC Card with a small hinged antenna which is hinged flush with the top of the PC Card when not in use, so that the antenna extends only slightly from the casing of the notebook computer into which the PC Card is inserted. FM radios typically also use a hinged, telescopically extensible antenna. When wireless communications are required, the antenna can be hinged outwards and extended as required.

A second kind of design is an antenna which is removable when not in use but which can be readily connected for use. An example would be a clip-on antenna for a PC Card offering wireless capabilities: a small antenna connects to the PC Card body via a high quality electrical connector.

The third kind of antenna is the permanently fixed antenna, for example the stub antenna as commonly found on mobile telephones.

These approaches all have disadvantages: the hinges of hinged antenna can often be readily damaged; removable antenna can be too readily lost and permanently fixed antennas are susceptible to damage. Another disadvantage with conventional designs is that the electrical connectors leading from the antenna to the radio receiver/transmitter circuitry have to carry radio frequency signals with high integrity and are therefore relatively expensive, high quality components.

One solution which partly addresses some of these drawbacks is to include the antenna on a platform which can slide out of a PC Card casing. Because the antenna is mounted on a retractable platform, it is both robust when extracted, cannot be lost and may also be fully retractable within the casing when not in use. Reference may be made to US 5918163 and EP 0936694. In these designs, the circuitry which processes digital signals (e.g. including the baseband processor) is not included on the platform which can slide out, but is instead mounted on a PCB fixed inside the PC Card casing. Hence, this art expUcitiy teaches placing analogue components alone on the slide out platform. Reference may also be made to US 5557288, which shows an antenna with associated analogue circuitry mounted on a platform which can be slid out of a portable computer casing. The antenna platform disclosed in this patent is not however entirely removable as such from the casing: instead it can merely slide out a short distance. This art therefore relates not to a PC Card type system which can readily be slotted into and withdrawn from a standard bay, but instead to a permanent, fixed structure in a computer. This art also expUcitiy teaches placing only analogue circuitry on the sUde out platform, although the precise function performed by this circuitry is not made expUcit.

The requirement to provide wireless communications capabiUties to electronic devices will become increasingly important as wireless communications becomes ever more pervasive. For example, recent developments in technology, such as the 802.11 and Bluetooth standards for short range radio, offer the possibiUty of connecting devices such as PDAs and laptop computers into Pico nets or local areas networks; Bluetooth and 802.11 enabled computers and peripherals wiU likely become popular wireless devices, able to transmit and receive wireless data with other compatible equipment, such as other computers and peripherals. Antennas and radio transceivers which can work with 802.11 and Bluetooth signals require high integrity electrical connections, so that the conventional solutions would be particularly expensive because of the required high quaUty of the components.

Summary of the Present Invention

In a first aspect of the invention, there is provided a removable wireless device which is adapted to be insertable and fully removable from a computing device, the wireless device comprising:

(i) an antenna;

(ϋ) an analogue radio ampUfier connected to the antenna; (iii) a platform on which the antenna and radio ampUfier are mounted, the platform being retractable into a casing of the device when the antenna is not in use and extendable out of the casing to enable the antenna to operate effectively;

wherein the device further comprises one or more components, mounted on the platform, which perform a digital process.

By placing at least some of the circuitry which appUes digital processes on the movable platform itself, significant manufacturing advantages can be obtained. For example, where the components perform digital processes such as signal detection or digital demodulation, then placing the components on a platform shared with the analogue radio ampUfier (and generaUy also the radio transceiver) leads to the expensive co-axial connections otherwise needed to bring a radio signal to a radio transceiver placed in the body of the PC Card being entirely eliminated. More generaUy, the component mounted on the platform may perform one or more of the foUowing digital processes: (i) D/A conversion;

(u) Signal filtering; (ui) Modulation or demodulation; (iv) Channel coding or de-coding; (v) Generating an analogue baseband signal;

(vi) Generating a digitised version of an analogue baseband signal.

The component may be a baseband processor and/or a radio transceiver.

The term 'computing device' used in this patent specification should be expansively construed to cover any form of data handling device, including without limitation a portable computer, desktop computer, communications device, mobUe telephone, desktop phone, smart phone or communicator. The platform may be a printed circuit board. The platform need not be a single unitary piece: the only requirement is for the part of the platform on which the antenna is attached to be fixed relative to the part of the platform on which the circuitry handling at least some digital signal processes is mounted. An advantage of mounting the antenna on a PCB shared with the related analogue transceiving circuitry and also at least some of the circuitry which can process or handle digital signals is that the required electrical connections can for example be a simple rigid connection such as a connection printed directly onto the printed circuit board.

The baseband processor is typically connected via a data connector interface to the computing device via cheap and robust fixed tracks. No high integrity cabUng needed to carry a wireless signal is therefore required at aU in such an implementation. In one implementation, several chips (typicaUy a physical interface, a baseband processor, a MAC (Media Access ControUer) and RAM are aU mounted on the retractable platform. Simple and relatively cheap fixed tracks or ribbon connectors then connect the MAC to a standard 68 way PCMCIA connector at the rear face of the card.

In a preferred embodiment, the platform sUdes within a PC Card casing conforming for example to a PCMCIA standard. The term 'PC Card' as used in this specification refers to any kind of smaU computer peripheral which can be placed into electrical engagement with a computer to provide directly or indirectly additional resources or functions for that computer or enable another connected device to use resources or functions of that computer. It includes cards such as PCMCIA cards, and CompactFlash (CF) cards, which are widely used with many different kinds of computer and offer a vast range of functionaUty, including voice and data communications, and memory expansion. PC Cards conform to precise physical and performance constraints and typicaUy slot into a standard si2ed bay in a computer host. Since PCMCIA card slots are so common in notebook and laptop PCs, this is a particularly convenient implementation since it means that a fuUy functional wireless radio device, for example a wireless LAN 802.11 or Bluetooth device, can be fitted to a wide range of computing devices. Conventional wireless LAN antennas are somewhat deUcate and readily broken, so that the robust solution offered by this embodiment is an attractive one.

The card may sUde out under the force of a spring ejection mechanism, have a motorised ejector or be merely puUed out manuaUy.

In accordance with a second aspect of the present invention there is provided a removable wireless device which is adapted to be insertable and fuUy removable from a computing device, the wireless device comprising: (i) an antenna;

(ii) an analogue radio ampUfier connected to the antenna ;

(iii) a platform on which the antenna and ampUfier are mounted, the platform being retractable into a casing of the device when the antenna is not in use and extendable out of the casing to enable the antenna to operate effectively;

wherein the device further comprises a sensor which detects the position of the platform and automaticaUy switches the wireless device on if the platform is extended beyond a first position and automaticaUy switches the wireless device off if the platform is retracted beyond a second position.

Hence, this second aspect envisages a wireless device, which may be a PC Card format device, which automaticaUy switches itself on and off depending on a sensed location of the extension of the antenna. Advantages of this approach are that (i) it does not require any software appUcation to switch on/off the radio and (ϋ) the status of the radio is immediately visible to a user. In accordance with a third aspect of the present invention, there is provided a PC Card including a removable platform on which is mounted at least one component, the platform being removable from the PC Card to aUow replacement by a platform on which is mounted a replacement or upgraded component by sUding the platform out of an aperture on the PC Card.

Hence, this third aspect of the present invention is based on the fact that the PC Card can readily operate as a host or base for one or more components which provide important functionaUty or features for the computer to which the PC Card is itself connected. For example, as noted above, a PC Card could include a Bluetooth antenna and radio module as the removable component. Digital signal processing circuitry and memory might reside permanently in the PC Card or also be removable, depending on the economics of each option. When the requirement for a different or upgraded antenna and/or radio module arises, a user need only swap the replaceable, removable component with the upgraded antenna and/or radio module. This wiU be significantly cheaper for the consumer than replacing the entire PC Card. Many other different kinds of components could be included in a PC Card and therefore upgraded in this way.

A modular system of different removable components may be avaUable: Having a PC Card with a standard aperture able to receive one of many different kinds of removable components, can significantly reduce manufacturing costs.

In a fourth aspect, there is a method of manufacturing a PC Card comprising the steps of:

(a) mounting a removable component on a platform, the platform being removable from the PC Card by a user to allow replacement by a replacement or upgraded component;

(b) sUding the platform into an aperture of the PC Card to engage with an electrical connector in the PC Card. In a fifth aspect, there is a method of upgrading the functionaUty of a PC Card comprising the foUowing steps:

(a) removing a component from the PC Card by sUding a platform on which that component is mounted out of an opening in the PC Card;

(b) taking an upgraded component mounted on a further platform and sUding that further platform into the opening in the PC Card.

Further detaUs of each aspect are stated in the appended claims.

Brief Description of the Drawings

The invention will be described with reference to the accompanying drawings, in which: Figure 1 is an exploded perspective view of a PC Card implementation of the present invention with a radio transceiver and baseband processor modules and an antenna mounted on a platform retractable within the PC Card;

Figure 2 is a perspective internal view of the PC Card implementation with the platform fuUy extended; Figure 3 is a perspective internal view of the PC Card implementation with the platform fuUy retracted;

Figure 4 is a perspective internal view of the PC Card implementation with the platform extended and showing the components fixed within the PC Card casing;

Figure 5 is a perspective internal view of the PC Card implementation with the platform retracted and showing the components fixed within the PC Card casing;

Figure 6 is a perspective external view of the PC Card implementation with the platform extended; Figure 7 is a perspective external view of the PC Card implementation with the platform extended;

Figure 8 is a perspective external view of part of the PC Card implementation showing a part which prevents the platform from being readily fuUy retracted;

Figure 9 is a perspective external view of part of the PC Card implementation showing a part which prevents the platform from being reacUly fuUy retracted;

Figure 10 is a perspective view of connector tracks used in the PC Card implementation;

Figure 11 is a schematic of the electronic components used in the PC Card.

Detailed Description

The detailed implementation shown in the attached figures is a PCMCIA format card which includes a 802.11 antenna, radio transceiver and baseband processor, aU mounted on a platform which can sUde in and out of the card casing. The card itself can be inserted into a standard PC Card bay in a laptop computer to give 802.11 standard short range radio connectivity for data transfer.

Referring now to Figure 1, the PC Card comprises a top metal cover 1 and a bottom metal cover 11, which provide electromagnetic screening to the electrical components positioned within them. A plastic frame 4 sits between the two metal covers 1 and 11; a fixed PCB 2 is positioned on frame 4 and includes at one end a standard PCMCIA 68 way connector 12, which in use electrically connects the PC Card to the lap top computer (not shown). A grounding cUp 3 is positioned on frame 4 such that when the PC Card is in use, it electricaUy contacts a grounded portion of the PCB 2 and also the top and bottom metal covers 1 and 11, thereby grounding each of those covers 1 and 11. A radio transceiver PCB 9 is a platform which is arranged to sUde in and out of frame 4 approximately 10mm, as shown more clearly in Figures 2 and 3. Radio transceiver PCB 9 has mounted upon it a radio transceiver unit 13; an inverted F antenna 14 and three LEDS 8 which indicate the functioning of the PC Card. Radio transceiver unit 13 is a Bluetooth radio chip such as the BlueCoreOl from Cambridge Silicon radio. Many other vendors also supply Bluetooth radio chips; further information can be found at the Bluetooth.com web site. The Bluetooth radio is a digital radio operating at 2.4GHz. Figures 2 and 3 show respectively the assembled PC Card with the top cover 1 removed and the combined antenna/radio transceiver platform 9 fuUy extended and fuUy retracted. As can be seen, with the platform 9 fully extended, antenna 14 fully protrudes from the card, clear of the shielding offered by the metal covers.

Additional signal processing components are also mounted on the radio transceiver PCB 9, including a baseband processor and RAM. In some implementations, a single component including several discrete chips (e.g. RF transceiver, Baseband and Unk manager) may be useful. The Bluemoon component from Infineon AG is one such example. A top radio cover 5 and bottom radio cover 10 is positioned around the end of the radio transceiver PCB 9 which in use may extend out of the PC Card.

Inverted F antenna 14 is a slim and cheap form of printed antenna and is therefore very suitable for a slim, low cost product such as a 802.11 or Bluetooth PC Card. Antenna 14 is positioned at the outer edge of the radio transceiver PCB 9 so that it extends substantiaUy from the top and bottom metal covers 1 and 11 when the platform, i.e. the radio transceiver PCB 9, is fuUy extended, as shown in Figures 2 and 7. LEDS 8 need to be visible at the front face of the radio transceiver PCB 9 but cannot overUe the antenna 14 since they and their leads would interfere with radio reception and transmission; LEDS 8 are therefore positioned back from the front face, but a Ught pipe 6 feeds Ught from them to the front face, as more clearly shown in Figures 2 and 3. LED(s) 8 are used in the antenna module to indicate the status or condition of the device, for example the received signal strength, Unk status, and data flow. The LEDs 8 can be modulated in intensity (for example the stronger the received signal, the brighter the LED), or on/off duty cycle (for example the stronger the received signal, the more rapidly the LED bUnks, or is on for longer). The LEDs 8 can for example pulse on for a short period each time a specified amount of data is transmitted or received. The user may specify which status each LED indicates and the means by which this is indicated. A combination of LEDs or multi-colour LED can be used to indicate status, for example colour could be varied from red, through orange to green could be used to indicated signal strength from none, weak through to strong.

A sUding connector 7 comprising a comb of eight metal fingers is positioned on the rear of the radio transceiver PCB 9; sUding connector 7 transfers digital signals to and from the signal processing circuitry on radio transceiver PCB 9, to the connector tracks 15, which are formed on the fixed PCB 2, as more clearly shown in Figures 4 and 5.

Figure 4 shows the PC Card from the rear; the holes of the PCMCIA 68 way connector 12 are clearly visible; these mate with pins located within the PC Card bay of the laptop computer (not shown). A PCMCIA interface chip 16, mounted on fixed PCB 2, is connected to 68 way connector 12 and receives digital signals passing along printed connector tracks 15 (and vice versa). Connector tracks 15 are in turn electricaUy connected to the 8 way sUding connector 7, as noted above.

As the platform 9 sUdes out of the PC Card, the 8 way sUding connector 7 sUdes along connector tracks 15, maintaining electrical contact. Electrical power to the radio transceiver 13 and other components on platform 9 passes through connector tracks 8 and sUding connector 7. Figure 10 shows the detaU of one of the connector tracks 15 in more detaU. A break 19 exists in one connector track; this enables a simple mechanism for sensing the position of the platform to be implemented as foUows: different voltages are appUed to the track 15 on one side of the break 19 as compared to the other side of the break 19. The voltage picked up by the contacting comb of 8 way connector 7 wiU be different depending on which side of the break 19 it is positioned. Suitable signaUing therefore enables the position of the platform 9 to be sensed so that when the platform is puUed out ready for operation, the PC Card is automaticaUy switched on; when the platform is pushed back in, then the appropriate power down process is automaticaUy initiated. This is useful for quick disabling as may be required, for example, on or when entering an aeroplane. The switch off is properly designed so that aU appropriate switch off protocols are foUowed - e.g. remotely connected devices know that the device is being turned off in a controUed manner. One advantage of this approach is that it does not require any software appUcation to switch on/ off the radio and the status of the radio is immediately visible to a user.

When the antenna is to be used, it can be readUy extended by the user gently pushing the front face of the radio covers 5 and 10. This causes a 1-way locking mechanism to be disengaged, aUowing a spring mounted on frame 4 to push platform 9 out. SmaU stops on the platform 9 ensure that it is not extended too far. When the user wishes to turn the wireless device off, then the user simply pushes platform 9 back into the PC Card casing and 1-way locking mechanism engages again.

Upgradeability

It is generaUy desirable to make computer products alterable or upgradeable to aUow for changes in the appUcable technical standards, or to add new or enhanced features. These "upgrades" can sometimes be implemented by updating the program memory associated with the micro-processor implementing the standard (or protocols). In some devices the program memory consists of volatile RAM and is downloaded from a host computer each time the device is used. In others it consists of non-volatile memory, for example flash memory. This memory may be updated from the host computer. Some communications products use program memory that does not faciUtate upgrading, for example ROM (readonly memory).

A software upgrade may however sometimes be inappUcable. For example where radio circuitry designed for one standard is not able to conform to the different or higher data speed modulations of a new standard, then a product incorporating that radio circuitry can be rendered obsolete. Some limited forms of hardware upgradeabiUty have been common in the computer field for many years; for example, RAM memory, hard drives and microprocessors can be swapped out and upgraded in many personal computers. However, engineering a product so that it is readUy upgradeable can add significantly to the complexity of the product and hence its manufacturing cost. For many consumer electronics products, profit margins are already highly pressured, making it difficult to justify reducing the margins further by adding upgradeabiUty features which may or may not be attractive to purchasers. The term 'upgraded component' denotes both a component with increased functionaUty and/or specification as weU as a component with a merely different functionaUty and/or specification.

The present invention addresses this issue: When the sUdable platform 9 is first mated into the PC Card frame 4 (typicaUy during first manufacture or a user upgrade procedure), a simple sUding engagement is enough to cause an adequate electrical connection between connector comb 7 and connector tracks 15. SUdable platform 9 can be entirely withdrawn without any damage to the PC Card or the sUdable platform 9. This is achieved as foUows: a smaU spring feature 20 (shown in Figure 8) is present on the sUdable platform 9. Feature 20 normaUy engages stop feature 21 (shown in Figure 9), positioned on frame 4, therefore preventing sUdable platform 9 from being fuUy withdrawn from frame 4. However, a more forceful puU can cause the spring feature 20 to be pushed to one side, aUowing the sUdable platform 9 to be withdrawn past stop feature 21. A sUdable platform 9 with upgraded components (not shown) can then readUy be sUd into the frame 4, automaticaUy engaging the connector tracks 15 when sufficiently inserted.

Signal Processing walk through

Figure 11 shows a simpUfied schematic of the main electronic components. As noted above, digital data is passed into a PCMCIA 68 way interface 12, controUed by PCMCIA interface 16. Digital data passes along fixed connector tracks 15 and is picked up by a siding connector 7 which is fixed to sUdable platform 9. SUdable platform 9 has mounted on it a baseband processor 30 as weU as a radio transceiver chip 13, feeding an antenna 14. The detailed operation of such a system will be appreciated by a skilled radio systems implementer and wiU therefore only be described in outUne here. The typical transmit sequence is as foUows: source digital data is received at the baseband processor from the laptop. At the baseband processor, the foUowing functions are carried out: first, channel coding occurs. In this process, the source digital data is multiplexed with forward error correction and framing bits. The purpose is to add redundancy to the information content so that bit errors can be detected in the receiver. A channel bitstream is generated as a result of the channel coding process. Digital modulation then occurs; the channel bitstream is merged to the signal samples which wUl be transmitted over the 2.4GHz air Unk. In Bluetooth, the GFSK digital modulation process occurs. The resultant signal is pulse shape filtered and then converted to analogue in a D/A converter. The analogue signal is then upconverted to the required frequency range and ampUfied to the required transmit power. The ampUfied signal is then passed to the antenna for transmission. The reception process is in essence the inverse of the above process.

The kind of components used to perform the above sequence can vary from implementation to implementation. For example, a baseband processor can be used to perform aU steps up to and including the D\A conversion, including Unk control and management functions, leaving the radio transceiver to perform solely the analogue signal processing functions of upconversion and ampUfication. In other implementations, the radio transceiver chip can itself perform significant digital signal processing tasks, such as modulation/demodulation; carry digital signals such as control logic signals (e.g. for controlUng an ampUfier); and perform digitaUy controUed power management tasks.

Claims

1. A removable wireless device which is adapted to be insertable and fuUy removable from a computing device, the wireless device comprising: (i) an antenna;

(n) an analogue radio ampUfier connected to the antenna ; (ϋi) a platform on which the antenna and radio ampUfier are mounted, the platform being retractable into a casing of the device when the antenna is not in use and extendable out of the casing to enable the antenna to operate effectively; wherein the device further comprises one or more components, mounted on the platform, which perform a digital process.

2. The removable wireless device of Claim 1 in which a component mounted on the platform perform one or more of the foUowing digital processes:

(i) D/A conversion;

(u) Signal filtering; (in) Modulation or demodulation; (iv) Channel coding or de-coding; (v) generating an analogue baseband signal;

(vi) generating a digitised version of an analogue baseband signal.

3. The removable wireless device of Claim 2 in which one or more of the foUowing components are mounted on the platform: (i) a baseband processor;

(ti) a radio transceiver.

4. The removable wireless device of any preceding Claim in which the platform comprises a printed circuit board.

5. The removable wireless device of Claim 4 in which electrical connections between the antenna and the or each component mounted on the platform are printed directly onto the printed circuit board on which the components and the antenna are mounted.

6. The removable wireless device of any preceding Claim in which the antenna is printed directly onto the circuit board.

7. The removable wireless device of any preceding claim in which the platform sUdes within a PC Card casing.

8. The removable wireless device of any preceding Claim in which the platform may sUde out under the force of a spring ejection mechanism, the force of a motorised ejector or be capable of being extracted manuaUy.

9. The removable wireless device of any preceding Claim in which the device further comprises a sensor which detects the position of the platform and automaticaUy switches the wireless device on if the platform is extended beyond a first position and automaticaUy switches the wireless device off if the platform is retracted beyond a second position.

10. The removable wireless device of Claim 9 in which the sensor comprises a voltage sensing arrangement in which the voltage appUed to a part of the platform varies depending on its position and the appUed voltage can be measured to determine the position of the platform.

11. The removable wireless device as claimed in any preceding Claim further including LEDs which are controUed to Ught up indicating the status or condition of the Card.

12. The removable wireless device of Claim 11 in which the LEDs are mounted distant from the antenna in order to minimise interference with the antenna and at least one Ught pipe carries Ught from the LEDS.

13. The removable wireless device of any preceding Claim in which the platform is fuUy removable from the device to aUow a new platform to be inserted into the device.

14. The removable wireless device of Claim 13 in which the removable platform enables an upgraded version of the platform to be inserted into the device.

15. A removable wireless device which is adapted to be insertable and fuUy removable from a computing device, the wireless device comprising:

(i) an antenna;

(n) an analogue radio ampUfier connected to the antenna;

(Hi) a platform on which the antenna and ampUfier are mounted, the platform being retractable into a casing of the device when the antenna is not in use and extendable out of the casing to enable the antenna to operate effectively; wherein the device further comprises a sensor which detects the position of the platform and automaticaUy switches the wireless device on if the platform is extended beyond a first position and automaticaUy switches the wireless device off if the platform is retracted beyond a second position.

16. The removable wireless device of Claim 15 wherein the device further comprises one or more components mounted on the platform which perform digital processes.

17. The removable wireless device of Claim 15 or 16 in which a component mounted on the platform handles one or more of the foUowing processes:

(i) D/A conversion;

(U) Signal filtering;

(Hi) Modulation or demodulation;

(iv) Channel coding or de-coding;

(v) generating an analogue baseband signal;

(vi) generating a digitised version of an analogue baseband signal.

18. The removable wireless device of Claim 17 in which one or more of the foUowing components are mounted on the platform:

(i) a baseband processor;

(H) a radio transceiver.

19. The removable wireless device of any preceding Claim 15 - 18 in which the platform comprises a printed circuit board.

20. The removable wireless device of any preceding Claim 15 - 19 in which electrical connections between the antenna and the or each component mounted on the platform are printed directly onto the printed circuit board on which the components and the antenna are mounted.

21. The removable wireless device of any preceding Claim 15 - 20 in which the antenna is printed directly onto the circuit board.

22. The removable wireless device of any preceding Claim 15 - 21 in which the platform sUdes within a PC Card casing.

23. The removable wireless device of any preceding Claim 15 - 22 in which the platform may sUde out under the force of a spring ejection mechanism, the force of a motorised ejector or be capable of being extracted manuaUy.

24. The removable wireless device of Claim 15 - 23 in which the sensor comprises a voltage sensing arrangement in which the voltage appUed to a part of the platform varies depending on its position and the appUed voltage can be measured to determine the position of the platform.

25. A PC Card including a removable platform on which is mounted at least one component, the platform being removable from the PC Card to aUow replacement by a platform on which is mounted a replacement or upgraded component by sUding the platform out of an aperture on the PC Card.

26. The PC Card of Claim 25 in which the removable platform includes an antenna.

27. The PC Card of Claim 25 or 26 in which the removable platform includes a radio module.

28. The PC Card of any preceding Claim 25 - 27 in which the removable platform is readUy disengageable from an electrical connector in the PC Card to aUow a user to remove the platform from the PC Card.

29. The PC Card of any preceding Claim 25 - 28 in which the first removable platform forms is reacUly engageable with an electrical connector in the PC Card during assembly of the PC Card.

30. The PC Card of any preceding Claim 25 - 29 in which comb/track connectors or push fit electrical connectors are used to connect the removable platform with an interface in the PC Card to permanent PC Card components.

31. The PC Card of any preceding Claim 25 - 30 forming part of a modular system in which the PC Card includes a standard aperture able to receive platforms on which many different kinds of components can be mounted.

32. The PC Card of any preceding Claim 25 - 31 in which the one or more sides of the removable platform when fuUy inserted into a housing in the PC Card are flush with a surface of the PC Card.

33. A method of manufacturing a PC Card comprising the steps of:

(b) sUding the platform into an aperture of the PC Card to engage with an electrical connector in the PC Card.

34. A method of upgrading the functionaUty of a PC Card comprising the foUowing steps:

(a) removing a component from the PC Card by sUding a platform on which that component is mounted out of an opening in the PC Card; (b) taking an upgraded component mounted on a further platform and sUding that further platform into the opening in the PC Card.

35. The method of Claim 34 whereby the action of sUding the platform out of the PC Card automaticaUy electricaUy disengages the component.