Hand-held transceiver as a modular unit

The present invention relates to a radio transceiver device according to the introduction of claim 1 and, in particular, the use of its hand-held transceiver as a modular unit.

Nowadays both car telephones and hand-held transceivers are used in the radio telephone networks. The major difference between them is that the car telephone has more output power and therefore also more requirements as to the noise and spurious response rejection. In this application the characteristics of the car telephone also refer to the characteristics of the hand-held transceiver and its amplifier or booster combinations.

The objective of the invention is to provide a hand-held transceiver the characteristics of which do not change in any essential way when making it connectable to an amplifier device. Then the characteristics of the assembly formed by the combination are essentially as good as those of the car telephones. Another aim of the present invention is to provide such a hand-held transceiver the use of which, as a whole or of its parts, will be possible in a modular way as different combinations in connection with amplifying devices.

Figure 1 shows a known embodiment to achieve multiple use where the connecting point between the hand-held transceiver 100 and the amplifying device 200 is the antenna connector A in Fig. 1. Instead of a normal antenna, the hand-held transceiver is connected with an amplifier or a booster. In this case the branchers or duplex filters D divide the transmission and reception frequencies within the amplifier into respective branches to be amplified respectively. In this known embodiment there is the disadvantage of the difficulty to obtain the characteristics required for hand-held transceivers. The two separate duplex filters between the hand-held transceiver and the booster add very much to the attenuation. The extensive amplifying required for the booster preamplifier then causes extensive requirements for the spurious response that cannot easily be carried out in the high-frequency element. This problem has been partly circumvented by adding the direct voltage input power in the hand-held transceiver. The increased power consumption leads, however, to a shortened life of the hand-held transceivers, or to the use of bigger batteries, thus being totally contrary to modern objectives.

EP-A-0 159 670 describes a radio communication device having a portable communication device and a power amplifier device for amplifying a transmitter output from the communication device. It further includes a detector circuit for detecting that an electrical coupling between the portable communication device and the power amplifier is established, thereby keeping the transmitter output power level to a minimum.

At the technology level, as in the above mentioned embodiment, it is necessary to use expensive components for the connections (among others, the filters required by the duplex devices). One of the objectives of the present invention is also providing cheaper connections.

The above mentioned objectives will, according to the invention, be reached by the characteristics of claim 1. In the transceiver, such an interface will be formed whereby the amplifier device can be connected in a simple way. This interface enables the optimized dimensions of the amplifying elements in the transceiver and in the amplifiers, by which it is possible, in an essential way, to eliminate the above mentioned higher requirements set for the technical level regarding the noise and spurious resonance levels. To achieve these objectives, the signal to be received has to be amplified in the amplifier element, in order to eliminate e.g. the above mentioned need to increase the current in the amplifier of the high-frequency amplifying element and in order to comply with the requirements of the equipment also when the amplifying element is connected to it.

According to the invention, the transceiver or its base element may also be used as a modular unit with the amplifier device for different purposes.

The invention is described in the following by using some embodiment examples and with references to the accompanying drawings where: <ul id="ul0001" list-style="none"><li>Fig. 1 shows a state-of-art level hand-held transceiver and a connector of the amplifying device; and</li><li>Fig. 2 shows a principle diagram of the interface of the base element of the hand-held transceiver according to this invention and its connection to the amplifier element and the amplifying device.</li></ul>

Fig. 2 shows a radio telephone device comprising a hand-held transceiver 1 connectable to a separate amplifying device 50. The hand-held transceiver 1 features a antenna connection 40 of its own and it may be operated fully independently as a radio telephone.

The hand-held transceiver 1 comprises the base element 10 and the high-frequency amplifier element 20 between which there is a defined interface including the terminals 11, 12, and 13 for the reception signal Rx, for the transmission signal Tx and, respectively, for the power level control signal Txc. The amplifying element includes a duplex filter 21, an input direction amplifier 22 and, in the branch of the output direction, amplifiers 23, 24 and the control circuits 25, 26 of the power level. Further structural details of the base element and those of the amplifying element are not described here in detail as they are well known as such.

The interface signals Rx and Tx may be connected to the amplifying element 20 or to the outer amplifying device 50 e.g. by the directional switches in the terminals 11, 12 or by power distribution/summing switch solutions (not shown) carried out by passive components. It is possible to switch into the control lines Txc of the transmitter directly and parallelly in terminal 13. The electric connections of the hand-held transceiver have been concentrated in terminal 30 for the connection of an outer amplifier; inside the hand-held transceiver there is a corresponding connection interface, e.g. in the form of a circuit card connector.

As the amplifying element 50 also includes the amplifier 52 of the received signal, the interface can be selected advantageously from the point of view of the signal levels and the high noise immunity and then it can be carried out without any specific and expensive radio frequency (RF) terminals. The interface can be, for specific purposes, selected as being of low, middle and/or radio frequency type.

The interface according to this invention, between the base element of the hand-held transceiver and the amplifying devices, is technically a good point. The transmission signal Tx level is still low at the terminal 12 because it will be amplified in the amplifying element. On the other hand, the received signal has already been amplified in the amplifying element, before switching it to terminal point 11. Thus the terminal will charge the hand-held transceiver and its base element as little as possible and the terminals can be selected as advantageous components. In addition, the interface is non-critical, as far as its characteristics are concerned, and thus it is possible to consider such an assembly where the hand-held transceiver 1 and the amplifier 50 are physically located farther away from each other as usual, spaced by several metres.

If needed, the hand-held transceiver 1 is connected through terminal 30 to a cable and by that to terminal 60 of the amplifying device 50. For this a Tx cable, a Rx cable, and a Txc and other control line wirings are needed. The amplifying device 50 in the circuit diagram of Fig. 2 essentially includes the same elements (51 to 56) as the amplifying element 20 of the hand-held transceiver (those from 21 to 26) although there may be differences in their dimensions, e.g. as regards the power levels. The amplifying device also includes an antenna terminal 70.

The amplifying device 50 is advantageously a so-called booster amplifier that can be used, in combination with the hand-held transceiver 1, for the car radio telephone characteristics. Alternatively, it is possible to consider that the amplifying device 50 is the amplifying element of the car radio telephone. In this case it is essential that both the booster and the car radio amplifier can be structurally and functionally identical whenever the hand-held transceiver according to this invention is used, including the described interface.

According to this invention, the hand-held transceiver 1 can be carried out without the amplifying element 20, i.e. the hand-held transceiver essentially includes just the base element 10 and the terminal 30 when the connecting elements at points 11 and 12 can be left out, if so desired. Such a hand-held transceiver with a solid connection with the amplifying device 50, may be used as a car telephone.

Using the interface between the hand-held transceiver and the amplifying element/amplification device described above, starting with same base elements, it is possible to design and manufacture several modular configurations, leading to considerable advantages from the point of view of product development and production.