Hand-held transceiver as a modular unit

Handset as a modular unit - Handtelefon i form av en modular enhet

The invention relates to a radiotelephone device according to the preamble of claim 1, and in particular to the use of its handset as a modular unit.

Today, radiotelephone networks use both car phones and handsets. The main difference between them is the higher output power of the car phone and the resulting higher requirements in terms of noise and spurious reproduction. In this application, the characteristics of a car telephone also refer to the characteristics of a combination of a handset and an amplifier device, i.e. a booster.

The object of the invention is to provide a handset whose characteristics do not change substantially in use, even if it can be connected to an amplifier device. In this case, the properties of the combination formed are substantially as good as with a car phone. Another object of the invention is to provide a handset which can be used in its entirety or in part in various combinations with amplifier devices.

Figure 1 shows a known attempt to achieve versatility, in which the connection point between the handset 100 and the amplifier device 200 is the handset antenna connector A in Figure 1. Instead of a normal antenna, the handset is connected to an amplifier device, i.e. a booster. In this case, the branchers, i.e. the duplex filters D, separate the transmission and reception frequencies inside the amplifier into their own branches, which are amplified accordingly. A disadvantage of this known implementation is the difficulty of implementing the features required of a handset. Two separate duplex filters between the handset and the booster increase the attenuation a lot. The high gain required of the booster's preamplifier then places great demands on spurious reproduction, which cannot easily be implemented in the high-frequency part of the handset. The problem has been partially circumvented by increasing the DC supply power to the handset. However, increased power consumption will result in reduced handset life or larger batteries, which is completely contrary to current targets.

In the state of the art, as in the above-mentioned implementation, expensive components (e.g. filters required by the duplex device) have to be used for the connections. It is also an object of the invention to provide more advantageous connections.

The above objects are achieved according to the invention by the features of claim 1. An interface is formed in the handset to which the amplifier device can simply be connected. Such an interface allows for optimal sizing of the amplifier components in the handset and amplifier devices, thus substantially avoiding the higher requirements for noise and spurious reproduction set forth in the prior art combination. According to the invention, the handset or its basic part can also be used as a modular unit with an amplifier device for different purposes.

The invention will now be described, by way of example, with reference to the accompanying drawings, in which:

Fig. 1 is a connection between a prior art handset and an amplifier device; and Fig. 2 is a schematic schematic diagram of the interface of the base part of the handset according to the invention and its connection to the amplifier part and the amplifier device.

Figure 2 shows a radiotelephone device comprising a handset 1 which can be connected to a separate amplifier device 50. The handset 1 has its own antenna connection 40 and can function as a completely independent radiotelephone.

The handset 1 comprises a base part 10 and a high-frequency amplifier part 20, between which an interface is defined with connection points 11, 12 and 13 for a reception signal Rx, a transmission signal Tx and a power level control signal Txc, respectively. The amplifier part has a duplex filter 21, an input amplifier 22, and in the output branch amplifiers 23, 24 and power level control circuits 25, 26. The other structure of the base part and the amplifier part will not be explained in more detail here, as they are known per se.

The interface signals Rx and Tx can be connected to the amplifier part 20 or to the external amplifier device 50, for example by directional switches at the connection points 11, 12 or by power distribution / adder switching solutions (not shown) implemented with passive components. The transmitter control lines Txc can be connected directly in parallel at connection point 13. The electrical connections of the base of the handset are centered on the connector 30 for connecting an external amplifier; inside the handset there is a corresponding interface, which may be in the form of a circuit board connector, for example.

The interface 30 can advantageously be selected in terms of signal levels and interference immunity, so that it can be implemented without special and expensive radio frequency (rf-) connectors. The interface can be selected as low, intermediate and / or radio frequency for certain purposes.

The interface between the basic part of the handset and the amplifier devices according to the invention is a technically good point. The level of the transmission signal Tx at the connection point 12 is still low because it is amplified in the amplifier section. On the other hand, the received signal Rx is already amplified in the amplifier part before it is connected to the connection point 11. Thus, the connection puts the least possible load on the handset and its base part, and the connectors can be selected as preferred components. In addition, the interface is non-critical in nature, so if necessary, it can be considered to install the devices in which the handset 1 and the amplifier device 50 are physically located farther than usual, several meters apart.

If necessary, the handset 1 is connected via the connector 30 to the cable and with it to the connector 60 of the amplifier device 50. This requires a Tx cable, an Rx cable and Txc and other control line wiring. In the circuit diagram of Fig. 2, the amplifier device 50 includes substantially the same parts (51-56) as the handset amplifier part 20 (parts 21-26), although there may be differences in their dimensioning, e.g., in terms of power level. The amplifier device also has an antenna connection 70.

The amplifier device 50 is preferably a so-called a booster amplifier which, in combination with the handset 1, can be used with car phone features. Alternatively, it may be thought that the amplifier device 50 is an amplifier part of a car radio telephone. In this case, it is essential that both the booster and the car radio amplifier can be structurally and functionally identical when using the handset according to the invention, in which the interface 30 is shown.

According to the invention, the handset 1 can be implemented without an amplifier part 20, i.e. the handset has essentially only a base part 10 and a connection 30, whereby the switching elements at points 11 and 12 can be omitted if desired. Such a handset, which is inextricably linked to the amplifier device 50, can be used as a car phone.

With the help of the interface between the handset and the amplifier part / amplifier device described above, several modular configurations can be designed and manufactured from the same basic parts, which provides a significant advantage for product development and production.