JP2003069445A - Antenna sharing device for transmitter-receiver of mobile phone - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mobile phone for conducting transmission/reception at the same time that reduces a current consumed in a transmission system so as to enhance the communication. SOLUTION: The antenna sharing device for transmitter-receiver is provided with a transmission power amplifier 102, a reception amplifier 103, and one antenna 100 connected to the transmission power amplifier 102 and the reception amplifier 103 for conducting the transmission operation or the reception operation or the transmission/reception at the same time, a transmitter side filter 105 disposed between the antenna 100 and the transmission power amplifier 102 to eliminate a noise at the transmitter side, a switch 107 whose one terminal is connected to an output of the transmitter power amplifier 102 and whose other terminal is connected to the antenna 100, a switch 110 whose one terminal is connected to an output of the transmitter side power amplifier 102 and whose other terminal is connected to the input of the transmitter side filter 105, and a switching control section 104 that controls only the switch 107 to be brought into a connection state when only the transmission is conducted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna sharing transmitter / receiver in which one antenna is shared between a transmitting side and a receiving side, and more particularly to an antenna sharing transmitter / receiver for a mobile telephone which performs simultaneous transmitting and receiving operations.

[0002]

2. Description of the Related Art TDM is used as a communication system for mobile telephones.
A (time division multiple access) method is known, and in recent years,
Packet services using the TDMA method have been performed. When performing a packet service in the TDMA system, a transmission system and a reception system are operated at the same time, and therefore a mobile phone capable of simultaneous transmission and reception is required. In addition, as mobile phones have become smaller and lighter in recent years, antenna sharing transceivers that share transmission and reception with a single antenna have become widespread, and antenna sharing transceivers that support simultaneous transmission and reception have been required. There is.

FIG. 3 is a diagram showing the configuration of a conventional antenna-shared transceiver of a mobile telephone that does not perform simultaneous transmission and reception in a TDMA mobile telephone. As shown in FIG. 3, the shared antenna transmission / reception device 3 includes an antenna 300 and an antenna duplexer 3 that communicate with a base station (not shown).
01, a transmission power amplifier 302 for amplifying a transmission signal,
A reception amplifier 303 that amplifies a reception signal and a switching control unit 304 are provided. The antenna duplexer 301 includes a switch 307, a switch 308, and a reception side filter 306. The switch 307 is turned on during transmission and the switch 3
08 is turned off. At the time of reception, the switch 308 is turned on and the switch 307 is turned off. Control of these switches is performed by the control unit 304. Receiver filter 3
06 is provided to remove noise outside the reception band.

Next, the operation of the transceiver sharing device 3 of FIG. 3 will be described. At the time of transmission, the transmission signal is amplified by the transmission power amplifier 302, and is transmitted from the antenna to the base station (not shown) via the switch 307. At the time of reception, the reception signal received by the antenna 300 passes through the switch 308, noise is removed by the reception side filter 306, is further amplified by the reception amplifier 303, and flows into the inside of the telephone.

Here, at the time of transmission, the transmission power amplifier 3
Since 02 causes a large current to flow through the amplification element, a high level of noise is generated even outside the transmission frequency band. If such noise outside the transmission frequency band flows into the reception system, the reception sensitivity will decrease. However, in the above-described conventional antenna shared transmitter / receiver 3, the receiving system does not operate at the time of transmission, and therefore the transmitting system has little influence on the receiving system. Therefore, the antenna duplexer 301 does not require a filter on the transmitting side to remove noise outside the transmission frequency band.

However, in the case of a mobile telephone which performs simultaneous transmission and reception, the influence of the transmission system on the reception system cannot be ignored, and therefore it is necessary to provide a filter on the transmission side to remove out-of-band noise of the transmission signal. FIG. 4 is a diagram showing an antenna shared transmitter / receiver of a conventional TDMA type mobile phone which performs a transmitting / receiving simultaneous operation. In the shared antenna transmission / reception apparatus 4 of FIG. 4, the shared antenna 401 includes the switch 307 and the transmission power amplifier 302 of the shared antenna 301 of FIG.
3 except that the transmission side filter 405 is inserted between the switch and the switch 307 and the control of the switches 308 are slightly different.
Since it has the same configuration as, the same configuration is denoted by the same reference numeral and description thereof is omitted. The switch control will be described. The switching control unit 404 turns on the switch 307 and turns off the switch 308 at the time of transmission, and turns on the switch 308 and turns off the switch 307 at the time of reception. Furthermore, the switch 307 and the switch 308 are turned on during simultaneous transmission and reception.

The operation of the antenna sharing transmitter / receiver 4 of FIG. 4 is almost the same as that of the antenna sharing transmitter / receiver 3 shown in FIG. 3, and the signal amplified by the transmitting power amplifier 302 at the time of transmission is transmitted to the transmitting side filter 405. The description is omitted because it is the same except that noise outside the transmission frequency band is removed.
During simultaneous transmission / reception, transmission and reception are performed at the same time, so the transmission signal is removed by the transmission-side filter 405 in order to prevent noise from the transmission system from flowing into the reception system.
With the above configuration, the influence of the transmission system on the reception system is reduced.

[0008]

However, when only transmitting / receiving with the antenna sharing transmitter / receiver 4 shown in FIG. 4 is performed, transmission power loss is reduced by the amount of the transmitting filter 405 as compared with the antenna sharing transmitter / receiver 3 shown in FIG. As a result, the transmission power amplifier 302 outputs a large amount of transmission output power. Therefore, there is a problem that the current consumed by the transmission power amplifier 302 increases.

An object of the present invention is to solve the above-mentioned conventional problems, and it is an object of the present invention to reduce the current consumed by the transmission system and improve the talk time in a mobile telephone that simultaneously operates transmission and reception. .

[0010]

According to a first aspect of the present invention, there is provided a shared antenna transmission / reception apparatus which includes a transmission circuit section (transmission power amplifier 102) for processing a transmission signal and a reception circuit section (reception section) for processing a reception signal. An antenna shared transmitter / receiver that includes an amplifier 103) and one antenna (antenna 100) connected to the transmitter circuit unit and the receiver circuit unit, and performs a transmission operation, a reception operation, or a transmission / reception simultaneous operation.
Noise removal means (transmission-side filter 10) provided between the antenna and the transmission circuit section for removing noise on the transmission side.
5), a first switch (switch 107) having one end connected to the output of the transmission circuit unit and the other end connected to the antenna, and one end connected to the output of the transmission circuit unit,
A control means for controlling only the first switch to be in a connected state when performing only a transmission operation with the second switch (switch 110) whose other end is connected to the input of the first noise removing means. (Switching control unit 104)

According to the antenna shared transmitter / receiver of the first aspect, in the antenna shared transmitter / receiver that simultaneously performs transmission / reception, when performing only the transmission operation, the transmission signal is sent to the antenna without passing through the transmission side filter. . Therefore, even when only the transmission operation is performed, it is possible to reduce the power loss in the transmission side filter as compared with the related art in which a signal is transmitted through the transmission side filter. Therefore, the current consumed in the transmission circuit unit can be reduced, and the talk time of the mobile phone equipped with the antenna sharing transmitter / receiver of the present invention can be extended.

According to a second aspect of the present invention, there is provided an antenna shared transmitter / receiver according to claim 1, wherein the first switch is one of two switches (switches 202 and 203) connected in series. It is characterized by

According to the second aspect of the present invention, when only the transmitting / receiving operation is performed by the antenna sharing transmitter / receiver which simultaneously performs the transmitting / receiving operation, the transmitting signal is sent to the antenna without passing through the transmitting filter. Therefore, even when only the transmission operation is performed, it is possible to reduce the power loss in the transmission side filter as compared with the related art in which a signal is transmitted through the transmission side filter. Furthermore, when performing only the transmission operation, two first switches are arranged in series. Therefore, in the simultaneous transmission / reception operation, the isolation of the path when only the transmission operation is performed can be doubled, and the influence from the transmission system to the reception system can be reduced. Therefore, deterioration of reception characteristics can be prevented.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (Embodiment 1) FIG. 1 is a diagram showing the configuration of an antenna common transmitter / receiver for a mobile telephone supporting TDMA packet service according to Embodiment 1 of the present invention. Transmitter / receiver with shared antenna 1 shown in FIG.
Is an antenna 100 for communicating with a base station (not shown),
Antenna duplexer 101, transmission power amplifier 102 for amplifying transmission signal, reception amplifier 10 for amplifying reception signal
3 and the switching control unit 104. The antenna duplexer 101 includes a transmission filter 105 that removes transmission signal out-of-band noise of a transmission signal, a reception filter 106 that removes reception-signal out-of-band noise, and switches 107 to 11
It consists of 0. The switches 107 to 110 are switching-controlled by the switching control unit 104.

The operation of the switching control unit 104 will be described. First, in the case of supporting voice services, only the switch 107 is turned on at the time of transmission, and only the switch 108 is turned on at the time of reception. In addition, during simultaneous transmission / reception operation, that is, during packet service, the switches 108, 109, and 11 are connected.
0 is turned on and the switch 107 is turned off.

The operation of the antenna sharing transmitter / receiver 1 having the above configuration will be described. In the case of supporting voice service, at the time of transmission, the transmission signal is amplified by the transmission power amplifier 102 and is transmitted from the antenna 100 to a base station (not shown) via a path different from the transmission side filter 105 by the switch 107.

When the packet service is supported, transmission and reception are performed simultaneously. At this time, the transmission signal is amplified by the transmission power amplifier 102. Transmission power amplifier 102
However, since a large current is passed through the amplification element, high noise is generated even outside the transmission frequency band, and this noise may flow into the reception system. In order to remove this noise, the transmission signal flows to the transmission side filter 105. The noise-free signal is transmitted from the antenna 100 to a base station (not shown) via the switch 109.

The signal received by the antenna 100 passes through the switch 108, and the receiving filter 106 removes noise. The reception-side filter 106 is provided to prevent the reception amplifier 103 from being saturated by the transmission signal from the transmission power amplifier 102 as the highest level reception frequency out-of-band signal. The signal from which the signal outside the reception frequency band has been removed is amplified by the reception amplifier 103 and flows inside the mobile phone.

As described above, the antenna shared transmitter / receiver 1 of the present embodiment transmits a signal without passing through the transmission filter 105 when performing only transmission. Generally, the power loss of the switch 107 is about 0.5 dB, and in FIG. 4, the power loss of the transmission side filter 405 is 1.5 dB.
The power loss of the switch 307 is about 0.5 dB. That is, even when only transmission is performed, the transmission side filter 405
With the above-described implementation, the power loss of about 1.5 dB can be improved as compared with the related art in which the signal is transmitted via the.
Therefore, the current consumed by the transmission power amplifier 102 can be reduced, and the call time of the mobile phone can be extended. (Embodiment 2) FIG. 2 is a diagram showing a structure of an antenna common transmitter / receiver of a mobile telephone supporting a TDMA system packet service according to Embodiment 2 of the present invention.
In this embodiment, the antenna duplexer 201 is similar to that shown in FIG.
The switch 107 of FIG.
Since the configuration is the same as that of the first embodiment except that it is changed to two, the same configuration is denoted by the same reference numeral, and detailed description of the configuration and the operation is omitted.

In this embodiment, when only transmission is performed,
The transmission signal is transmitted from the antenna 100 via the switches 202 and 203. Where switches 202 and 2
The power loss at 03 is about 1 dB in total, and in FIG. 4, the power loss at the transmitting filter 405 is 1.5 dB.
The power loss of the switch 307 is about 0.5 dB. In other words, compared to the conventional technique in which a signal is transmitted via the transmission filter 405 even during transmission only, the above-mentioned implementation can improve the power loss of about 1 dB. Therefore, the current consumed by the transmission power amplifier 102 can be reduced, and the call time of the mobile phone can be extended.

In the first embodiment, when the transmission / reception simultaneous operation is performed, the switch 107 is turned off, but even in this case, the switch element is not in a completely short-circuited state. Therefore, the signal outside the transmission frequency band from the transmission power amplifier 102 passes through the switch 107 and the reception amplifier 103.
It may leak to the side. Therefore, it is necessary to increase the isolation between the transmission power amplifier 102 and the reception amplifier 103. What is isolation?
At the time of transmission, the power amplifier for transmission 102 to the antenna 100
Signal output correctly to the power amplifier for transmission 102
Is the ratio of the signal leaking from the receiver to the receiving amplifier 103 and flowing. That is, the high isolation means that the power amplifier 102 for transmission is connected to the amplifier 103 for reception.
It means that there are few signals flowing to.

Therefore, in the second embodiment, the switches turned on at the time of voice service are the switches 202 and 203.
It consists of two. Generally, the isolation of one switch is about 25 dB, and the total isolation of the switches 202 and 203 is about 50 dB. By providing two switches in the route used only for transmission, it is possible to secure higher isolation than when one switch is used, and the influence from the transmission system to the reception system during simultaneous transmission / reception operation (during packet service) Can be suppressed and the reception characteristics can be secured.

[0023]

According to the present invention, it is possible to reduce the current consumed in the transmission system and improve the talk time in a mobile telephone which simultaneously performs transmission and reception. Further, it is possible to suppress the influence of the transmission system on the reception system and suppress the deterioration of the reception characteristics.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of an antenna sharing transmitter / receiver of a mobile phone supporting a TDMA packet service according to a first embodiment.

FIG. 2 is a diagram showing a configuration of an antenna common transmitter / receiver of a mobile phone compatible with a TDMA system packet service according to a second embodiment.

FIG. 3 is a diagram showing a configuration of a conventional antenna shared transmitter / receiver of a mobile phone that does not perform transmission / reception simultaneous operation.

FIG. 4 is a diagram showing a configuration of a conventional antenna shared transmitter / receiver of a mobile phone, which performs simultaneous transmitting and receiving operations.

[Explanation of symbols]

1, 2, 3, 4 Antenna sharing transceiver 100, 300 Antenna 101, 201, 301, 401 Antenna duplexer 102, 302 Transmission power amplifier 103, 303 Reception amplifier 104, 204, 304, 404 Switching control unit 105, 405 transmission side filter 106, 306 reception side filter 107, 108, 109, 110 switch 202, 203, 307, 308 switch

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Claims (2)

[Claims] 1. A transmission circuit unit that processes a transmission signal, a reception circuit unit that processes a reception signal, and a transmission circuit unit and one antenna connected to the reception circuit unit. , Or an antenna shared transmitter / receiver for a mobile phone that performs simultaneous transmission / reception operations, wherein noise elimination means for eliminating noise on the transmission side provided between the antenna and the transmission circuit section and one end of the transmission circuit section A first switch connected to the output and having the other end connected to the antenna; and a second switch having one end connected to the output of the transmission circuit section and the other end connected to the input of the noise removing means. And a control means for controlling only the first switch to be in a connected state when performing only a transmission operation. 2. The antenna shared transmitter / receiver for a mobile phone according to claim 1, wherein the first switch comprises two switches connected in series.