JPH11261438A - Radio communication circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To check high frequency RF characteristics of a transmission section without being affected electrically by an antenna by throwing a 1st switch to electrically connect a reception section to the antenna and throwing a 2nd switch to electrically connect the transmission section to the antenna. SOLUTION: A 1st terminal T4 is connected to a 3rd terminal T6 electrically by a 1st switch S2 and a 2nd terminal T5 is connected to a 4th terminal T7 electrically by a 2nd switch S3. As a result, a transmission section 9 is connected electrically to an RF connector 21 and a reception section 8 is connected electrically to an antenna 11. In this case, an electric circuit when viewing a transmission section 9 from a plug section is electrically isolated from an electric circuit when viewing the reception section 8 from the antenna 11. Thus, the impedance of the one electric circuit is not affected by the other electric circuit and kept to be, e.g. 50 ohms.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio communication circuit provided with a transmission / reception switch for connecting an antenna to either a receiving section or a transmitting section.

[0002]

2. Description of the Related Art A circuit configuration of a wireless communication circuit 1 used in a general wireless device will be described with reference to FIG.

[0003] The radio communication circuit 1 has a radio frequency RF (Radio Fr.
equency) It is roughly divided into a module unit 2 and a data processing unit 3. If necessary, the data processing unit 3 is connected to, for example, a speaker 4, a microphone 5, or a key input unit 6 for inputting information.

The high-frequency RF module 2 includes a transmission / reception switch 7
, A receiving unit 8, a transmitting unit 9, and a synthesizer unit 10. In the high-frequency RF module 2, transmission and reception are switched by connecting the antenna 11 to one of the reception unit 8 and the transmission unit 9 via the transmission / reception switch 7. That is, the transmission / reception switch 7 is provided with three terminals, the first terminal T1 is connected to the reception unit 8, the second terminal T2 is connected to the transmission unit 9, and the third terminal T3 is connected to the antenna 11. Connected. The third terminal T3 is connected to the switch S1
Thereby, it is connected to either the first terminal T1 or the second terminal T2.

[0005] In the receiving section 8, the input signal RX received via the antenna 11 and the transmission / reception switch 7 is mixed with a local signal supplied from the synthesizer section 10,
An IF (Intermediate Frequency) signal in the intermediate frequency band is formed. The IF signal is connected to the high-frequency RF module 2 and output to a data processing unit 3 including a baseband circuit, a control circuit, and the like. Further, the signal processed by the data processing unit 3 is output as voice from the speaker 4, for example.

The information input from the microphone 5 or the key input unit 6 is processed by the data processing unit 3,
Is output to In the transmitting section 9, the signal processed by the data processing section 3 is modulated, and further the signal is processed by the synthesizer section 1.
The transmission signal TX is formed by mixing with the local signal given from 0. The transmission signal TX is transmitted to the transmission / reception switch 7.
And transmitted via the antenna 11.

[0007] Impedance matching is required between the wireless communication circuit 1 and the antenna 11. In particular,
When the antenna 11 and the receiving unit 8 are connected via the transmission / reception switch 7, the impedance of the electric circuit when viewed from the antenna 11 to the receiving unit 8 and the impedance of the antenna 11 must be the same. If impedance matching is not achieved, problems such as the input signal RX being attenuated in the receiving unit 8 will occur. When the antenna 11 and the transmission unit 9 are connected via the transmission / reception switch 7, the impedance between the electric circuit and the antenna 11 when the transmission unit 9 is viewed from the antenna 11 is viewed.
The dance must be the same. If impedance matching is not achieved, problems such as the output signal TX being reflected by the antenna 11 occur. For this reason, the circuit is usually designed so that each impedance is 50Ω.

[0008] The receiving unit 8 and the transmitting unit 9 are composed of RCR (Research & Development Center for Radio).
Systems) standards specify high-frequency RF characteristics such as modulation accuracy and transmission power. Receiver 8 and transmitter 9
When the high-frequency RF characteristics are inspected, a measuring instrument for inspection is used. In the inspection of the high-frequency RF characteristics in the receiving unit 8, the pseudo input signal generated by the measuring device
Is input to In the inspection of the high-frequency RF characteristics in the transmission unit 9, a pseudo output signal generated by the transmission unit 9 is output to a measuring instrument.

When testing the high-frequency RF characteristics, an antenna is connected to each of the measuring instrument and the wireless communication circuit 1, and a pseudo input signal is input to the receiving unit 8 using radio waves, or the transmitting unit 9 is used using radio waves. Can output a pseudo output signal to the measuring instrument. However, when a pseudo input signal or a pseudo output signal is transmitted and received using radio waves, the high-frequency RF characteristics of the receiving unit 8 and the transmitting unit 9 vary due to the sensitivity or positional relationship of the connected antenna, and a constant test result cannot be obtained. . Therefore, in the RCR standard,
It is stipulated that the measuring device and the wireless communication circuit 1 are electrically connected by wire, and the high-frequency RF characteristics of the receiving unit 8 and the transmitting unit 9 are inspected.

Next, a circuit board 12 on which the wireless communication circuit 1 is mounted will be described with reference to FIGS. Note that the circuit board 12 shows a peripheral portion where the transmission / reception switch 7 is mounted, and other portions are omitted.

The transmission / reception switch 7 is mounted on the surface of the circuit board 12. The first terminal T1 of the transmission / reception switch 7 is electrically connected to the reception section 8 via the wiring pattern 13A.
The second terminal T2 is electrically connected to the transmission unit 9 via the wiring pattern 13B. The third terminal T3 is electrically connected to a land 14 to which the antenna 11 is soldered via a wiring pattern 13C. The third terminal T3 is
Wiring pattern 13D branched from wiring pattern 13C
Are electrically connected to the lands 15 via the. Land 15
Is provided with connection means for electrically connecting the measuring instrument and the wireless communication circuit 1 by wire. Usually, an RF connector is used as the connection means, and a plug portion 16 of the RF connector is soldered to the land 15. When testing the high-frequency RF characteristics, the plug 16 is connected to a jack 18 of an RF connector provided at one end of a cable 17 for electrically connecting the measuring instrument and the wireless communication circuit 1.

When the high-frequency RF characteristics of the receiving unit 8 and the transmitting unit 9 are inspected, the impedances of the electric circuits of the receiving unit 8 and the transmitting unit 9 viewed from the plug unit 16 are set to, for example, 50Ω. There is a need. Land 14
When the antenna 11 is soldered to the
The impedance of the electric circuit on the receiving section 8 side and the transmitting section 9 side deviates from 50Ω. For this reason, when inspecting the high frequency RF characteristics of the receiving unit 8 and the transmitting unit 9, the inspection is performed without soldering the antenna 11 to the land 14.

After inspecting the high-frequency RF characteristics of the receiving unit 8 and the transmitting unit 9, the antenna 11 is soldered to the land 14. At this time, the receiving unit 8 viewed from the antenna 11
The impedances of the electric circuits on the transmission side and the transmission section 9 must be set to, for example, 50Ω. However, when the plug portion 16 is soldered to the land 15, an impedance component, a parasitic capacitance component, and an inductance component are generated between the land 15 and the plug portion 16. The impedance of the electric circuit on the transmission unit 9 side deviates from 50Ω. Therefore, when the antenna 11 is soldered to the land 14, a part of the wiring pattern 13D is cut off, and the land 15 and the plug 16 are electrically insulated from the wireless communication circuit 1.

[0014]

However, the high-frequency R of the receiving unit 8 and the transmitting unit 9 mounted on the circuit board 12 is different.
Since the wiring pattern 13D is cut after the inspection of the F characteristic, the manufacturing process of the wireless device is complicated. In recent years, there has been an increasing demand for miniaturization of wireless devices. For this reason, there is a problem that the wiring pattern of the circuit board 12 is increased in density, and when the wiring pattern 13D is cut, other wiring patterns are erroneously cut. Further, once the wiring pattern 13D has been cut, it is difficult to connect the cut wiring pattern 13D even if it is desired to inspect the high-frequency RF characteristics of the receiving unit 8 and the transmitting unit 9 again. In reality, there is a problem that the retest cannot be performed.

Accordingly, an object of the present invention is to provide a wireless communication circuit for solving the above-mentioned problem.

[0016]

A radio communication circuit according to the present invention is configured as follows to achieve the above object.
That is, in a wireless communication circuit including a transmission / reception switch electrically connecting an antenna to one of a reception unit and a transmission unit, the transmission / reception switch includes a first switch and a second switch, and The switching unit is provided with a connection unit with a measuring device for inspecting a high-frequency RF characteristic of the wireless communication circuit, and the first switch electrically connects the reception unit to the connection unit or the antenna. The second switch electrically connects the transmitting unit to the connection unit or the antenna.

When the high frequency RF characteristic of the receiving section is inspected, the receiving section is electrically connected to the connecting means by the first switch. That is, the receiving unit is electrically connected only to the connection unit, and is not electrically connected to the antenna.
In this case, the transmitting unit and the antenna may or may not be connected by the second switch. Therefore, it is possible to inspect the high-frequency RF characteristics of the receiving unit without being influenced by the antenna. On the other hand, when inspecting the high-frequency RF characteristics of the transmitter,
The transmission unit is electrically connected to the connection unit by the second switch. That is, the transmission unit is electrically connected only to the connection unit, and is not electrically connected to the antenna. In this case, the receiving unit and the antenna may or may not be connected by the first switch. For this reason,
Inspection of the high-frequency RF characteristics of the transmission unit can be performed without being influenced by the antenna. When performing reception, the antenna and the receiving unit are connected by the first switch. In this case, the second switch may or may not connect the connection unit and the transmission unit. When performing transmission, the antenna and the transmission unit are connected by the second switch. In this case, the first switch may or may not connect the connection unit and the reception unit.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A radio communication circuit 19 according to the present invention will be described with reference to FIG. The configuration different from the wireless communication circuit 1 shown in FIG. 5 is different from that of the transmission / reception switching device 20 and the connection between the measurement device and the transmission / reception switching device 20 when the high-frequency RF characteristics of the wireless communication circuit 19 are inspected. That is, connection means is provided. As the connecting means, an RF connector is generally used because of easy handling. For this reason, a case where the plug section 21 of the RF connector is connected to the transmission / reception switch 20 is shown as an example. Hereinafter, the transmission / reception switch 20 and the plug unit 21 will be described, and description of other components will be omitted.

The transmission / reception switch 20 is provided with four terminals, a first terminal T4 is connected to the reception unit 8, a second terminal T5 is connected to the transmission unit 9, and a third terminal T6 is connected to the antenna 11 , And the fourth terminal T7 is connected to the plug portion 21 of the RF connector. The first terminal T4 is electrically connected to one of the third terminal T6 and the fourth terminal T7 via the first switch S2. The second terminal T5 is electrically connected to one of the third terminal T6 and the fourth terminal T7 via the second switch S3.

Next, the circuit board 22 on which the wireless communication circuit 19 is mounted will be described with reference to FIGS. Note that the circuit board 22 shows a peripheral portion where the transmission / reception switch 20 is mounted, and other portions are omitted.

A transmission / reception switch 20 is provided on the surface of the circuit board 22.
Is implemented. The first terminal T4 of the duplexer 20 is electrically connected to the receiver 8 via a wiring pattern 23A. The second terminal T5 is electrically connected to the transmitting unit 9 via the wiring pattern 23B. The third terminal T6 is electrically connected to the land 24 via the wiring pattern 23C. The antenna 11 is soldered to the land 24.
The fourth terminal T7 is electrically connected to the land 25 via a wiring pattern 23D. The plug portion 21 is soldered to the land 25.

Next, the case where the high-frequency RF characteristics of the wireless communication circuit 19 are inspected will be described.

First, referring to FIG.
The case where the F characteristic is inspected will be described.

The first terminal T4 is electrically connected to the fourth terminal T7 by the first switch S2. In addition, the second terminal T5 is electrically connected to the third terminal T6 by the second switch S3. As a result, the receiving unit 8 is electrically connected to the plug unit 21, and the transmitting unit 9 is connected to the antenna 1
1 and is electrically connected. At this time, the electric circuit C1 as viewed from the plug unit 21 toward the receiving unit 8 is electrically insulated from the electric circuit C2 as viewed from the antenna 11 toward the transmitting unit 9. Therefore, the impedance of the electric circuit C1 is not affected by the electric circuit C2 and is, for example, 50Ω.
Is kept.

The plug 21 is connected to a jack 18 of an RF connector provided at one end of a cable 17 for electrically connecting a radio communication circuit 19 and a measuring instrument. An inspection of the characteristics is performed. When the high-frequency RF characteristics of the receiving unit 8 are inspected, the second terminal T5 and the third terminal T6 need not be electrically connected by the second switch S3.

Next, referring to FIG.
The case where the F characteristic is inspected will be described.

The first terminal T4 is electrically connected to the third terminal T6 by the first switch S2. The second terminal T5 is electrically connected to the fourth terminal T7 by the second switch S3. As a result, the transmitting unit 9
The receiving section 8 is electrically connected to the antenna 11 while being electrically connected to the F connector 21. At this time, the plug 21
The electric circuit C3 viewed from the side of the transmission unit 9 from the
Is electrically insulated from the electric circuit C4 as viewed from the receiving unit 8 side. Therefore, the impedance of the electric circuit C3 is not affected by the electric circuit C4, for example, 50
Is kept at Ω.

The plug 21 is connected to a jack 18 of an RF connector provided at one end of a cable 17 for electrically connecting a radio communication circuit 19 and a measuring instrument. An inspection of the characteristics is performed. When the high-frequency RF characteristics of the transmitting unit 9 are inspected, the first terminal T4 and the third terminal T6 need not be electrically connected by the first switch S2.

When the high-frequency RF characteristics of the wireless communication circuit 19 are not inspected, the plug 21 for connecting to the measuring instrument is not used. That is, when receiving, the first switch S2 operates to electrically connect the receiving unit 8 and the antenna 11. When transmitting, the second switch S3 performs an operation for electrically connecting the transmitting unit 9 and the antenna 11.

The operation of electrically connecting the first terminal T4 to either the third terminal T6 or the fourth terminal T7 by the first switch S2 is usually performed by using a microcomputer. Controlled. The operation of electrically connecting the third terminal T5 to either the third terminal T6 or the fourth terminal T7 by the second switch S3 is similarly controlled using a microcomputer. You.

[0031]

The radio communication circuit according to the present invention has the following effects because it is configured as described above. That is, despite the state in which the antenna and the connection means are electrically connected to the wireless communication circuit, the high-frequency RF characteristics of the wireless communication circuit can be inspected while keeping the impedance constant. Further, the inspection of the high-frequency RF characteristics of the wireless communication circuit can be repeatedly performed. Further, since the wiring pattern for connecting the wireless communication circuit and the plug is not cut off after inspecting the high-frequency RF characteristics of the receiving unit and the transmitting unit as in the related art, the manufacturing process is simplified, and Thus, the accident of cutting other wiring patterns is prevented, and the production yield is improved. Therefore, the wireless device can be manufactured at low cost.

[Brief description of the drawings]

FIG. 1 is a diagram showing a wireless communication circuit according to the present application.

FIG. 2 is a perspective view showing a periphery of a transmission switch on a circuit board on which a wireless communication circuit according to the present application is mounted.

FIG. 3 is a diagram showing a connection operation of a first switch and a second switch provided in a transmission switch of the wireless communication circuit according to the present application, wherein the first switch connects a receiving unit and a plug of an RF connector. FIG.

FIG. 4 is a diagram showing a connection operation of a first switch and a second switch provided in a transmission switch of the wireless communication circuit according to the present application, wherein a transmission unit and a plug of an RF connector are connected by a second switch; FIG.

FIG. 5 is a diagram illustrating a general wireless communication circuit.

FIG. 6 is a perspective view showing a periphery of a transmission switch on a circuit board on which a general wireless communication circuit is mounted.

FIG. 7 is a circuit diagram showing a periphery of a transmission switch on a circuit board on which a general wireless communication circuit is mounted.

[Explanation of symbols]

 High-frequency module 2 Data processing unit 3 Receiving unit 8 Transmitting unit 9 Antenna 11 Wireless communication circuit 19 Transmission / reception switch 20 RF connector plug unit 21 First switch S1 Second switch S2

(72) Inventor Yasutaka Maekawa 2-26-10 Tenjin, Nagaokakyo-shi, Kyoto Prefecture Murata Manufacturing Co., Ltd.

Claims (1)

[Claims] 1. A wireless communication circuit including a duplexer for electrically connecting an antenna to either a receiver or a transmitter, wherein the duplexer includes a first switch and a second switch. And a measuring device connecting means, the first switch electrically connects the receiving section to the connecting means or the antenna, and the second switch electrically connects the transmitting section to the connecting means or the antenna. A wireless communication circuit, wherein the wireless communication circuit is electrically connected.