JPH10308685A - Transmission/reception circuit unit for radio equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To permit a high frequency amplifier to execute transmission and reception, to miniaturize it and to reduce cost. SOLUTION: A first switch circuit 16 connects a modulation circuit 18 with the input terminal 14a of an amplifier circuit 14, interrupts connection between an antenna 20 and the input terminal 14a of the amplifier circuit 14 at the time of transmission, interrupts connection between the modulation circuit 18 and the input terminal 14a of the amplifier circuit 14, and connects an antenna 20 with the input terminal 14a of the amplifier circuit 14 at the time of reception. A second switch circuit 22 interrupts a demodulation circuit 24 and the output terminal 14b of the amplifier circuit 14, connects the antenna 20 with the output terminal 14b of the amplifier circuit 14 at the time of transmission, connects the demodulation circuit 24 with the output terminal 14b of the amplifier circuit 14, and interrupts connection between the antenna 20 and the amplifier circuit at the time of reception. The amplifier circuit 14 is used for transmission and reception by switch operation of the first and second switch circuits 16 and 22.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission / reception circuit unit used for a radio device.

[0002]

2. Description of the Related Art Radio apparatuses exchange data confirmation signals in order to transmit data accurately. Basically, it is classified into a transmitting device and a receiving device, but performs bidirectional communication, and both have a transmitting circuit and a receiving circuit. Since the communication uses the simplex system, the receiving circuit and the transmitting circuit are exclusively used. In the conventional method, FIG.
As shown in (1), the transmission high-frequency amplification circuit (2) and the reception high-frequency amplification circuit (4) are independent, and when one is operating, one is at rest.

In FIG. 3, at the time of transmission, a modulated signal output of a modulation circuit (6) is amplified by a transmission amplification circuit (2) and supplied to an antenna (10) via a switching circuit (8).
Further, at the time of reception, the switching circuit (8) is switched, the connection between the amplifier circuit (2) and the antenna (10) is cut off, and the modulated wave absorbed by the antenna (10) passes through the switching circuit (8). It is configured to be input to the reception amplification circuit (4), amplified here, and then demodulated by the demodulation circuit (12).

[0004]

The high-frequency amplifier circuit requires a resonance circuit for input and output, and it is difficult to reduce the size of the resonance circuit, and it requires adjustment. Therefore, the provision of two high-frequency amplifiers has a problem that the size of the transmission / reception circuit unit becomes large and the cost increases. An object of the present invention is to solve the above problems.

[0005]

SUMMARY OF THE INVENTION To achieve the above object, the present invention provides a radio apparatus comprising a modulation circuit, a demodulation circuit, and an amplification circuit for amplifying transmission and reception modulated signals. In the transmission / reception circuit unit for
Connects between the modulation circuit and the input terminal of the amplifier circuit and cuts off between the antenna and the input terminal of the amplifier circuit, and cuts off between the modulation circuit and the input terminal of the amplifier circuit during reception. And a first switching circuit that connects between the antenna and the amplifier circuit, and that, during transmission, cuts off between the demodulation circuit and the output terminal of the amplifier circuit and connects the antenna and the output terminal of the amplifier circuit. And a second switching circuit that connects between the demodulation circuit and the output terminal of the amplification circuit and disconnects between the antenna and the amplification circuit during reception. This is also used for reception.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of the present invention will be described below with reference to the embodiments of the present invention shown in the attached drawings.
(14) is a high-frequency amplifier circuit for both transmission and reception, (16)
The contact (16a) is connected to the input terminal (1) of the amplifier circuit (14).
4a), a modulation circuit (18) is connected to one contact (16b) of the two contacts (16b) (16c) of the switching circuit (16). An antenna (20) is connected to the other contact (16c).

A second switching circuit (22) has a contact (22a) connected to the output terminal (14b) of the amplifying circuit (14), and has two contacts (22b) of the switching circuit (22).
Of the contacts (22c), the demodulation circuit (24) is connected to one contact (22c), and the antenna (20) is connected to the other contact (22b). The first switching circuit (1
6) One of the two contacts (16b) (16c) is electrically selected and connected to the contact (16a).

The second switching circuit (22) electrically selects one of the two contacts (22b) (22c) and connects it to the contact (22a).
Each of the above circuits is a unitized transmission and
A receiving circuit (24) is configured. In the above configuration, when the circuit (24) operates as a transmission circuit,
The contacts (16b) and (16a) of the first switching circuit (16) are electrically connected, and the contacts (16c) and (16a) are disconnected.

The second switching circuit (22) has a connection between the contacts (22a) and (22b) and a contact (22a) (2
2c) is cut off. Thereby, the modulation circuit (1)
The output of 8) passes through the switching circuit (16), and passes through the amplifier circuit (1).
4), where it is amplified and switched to the switching circuit (2).
After 2), it is supplied to the antenna (20). When the transmitting / receiving circuit (24) operates as a receiving circuit, the first
The contacts (16c) and (16a) of the switching circuit (16) are electrically connected, and the contacts (16b) and (16a) are disconnected. Further, the second switching circuit (22) includes a contact (22)
a) and (22c) are connected, and the contacts (22a) and (22b)
The space is cut off.

Thus, the radio wave from the antenna (20) is input to the amplifier circuit (14) via the switching circuit (16), where it is amplified and passed through the switching circuit (22) to the demodulation circuit. (24). The transmission / reception circuit (24) is used for various wireless devices that perform two-way communication. FIG. 2 shows this circuit (2
4 shows an embodiment using (4). A printer connector of a personal computer (26) and a printer (28) as an output device of the computer are provided on a casing of the wireless printer sharing device via a connector (not shown).
The microcomputer includes an I / O port (30) for connecting to a computer connector of the present invention, a CPU (central processing unit) (32), and a memory (34).

A transmission / reception circuit (24) is connected to the CPU (32) via a UART (general-purpose asynchronous receiver transmitter). (38) is a power supply circuit, (4)
0) is a switching circuit, (42) is a high-pass filter circuit composed of a capacitor, and (44) is a low-pass filter circuit composed of a choke, and these circuits are connected as shown.

The power supply circuit (38) is connected to an AC adapter (46) via a low-pass filter circuit (44), and the input / output section of the transmission / reception circuit (24) is connected to a high-pass filter (42). ) Is connected to a power cord (48) also serving as an antenna of the AC adapter (46). For example, two personal computers (26) and (26) are connected to one printer (2).
8), the wireless printer sharing device (5)
0) are prepared, and the sharing device (50) is attached to each of the personal computers (26) (26) and the printer (28) one by one. The sharing device (50) is a personal computer (26)
A connector compatible with the printer connector of (26) and the computer connector of the printer (28) is integrally provided.

Therefore, the attachment of the shared device (50) to the personal computer (26) (26) or the printer (28)
All you have to do is plug the connector into your computer or printer. The sharing device (50) attached to the personal computer (26) (26) is mainly used as a print data transmitting device, and the sharing device (50) attached to the printer (28) is used as a print data receiving device.

Of the two personal computers (26) and (26),
The print data and graphic print data of one personal computer are sent to the CPU (3) via the I / O port (30) of the shared device (50).
The data is transferred to the buffer memory (34) by the processing operation 2). Printing stored in the buffer memory (34),
The graphic print data is sent via the UART (36) to the transmission / reception circuit (24) in the transmission mode, where it is amplified and modulated therefrom and sent from the antenna (48) to the shared device (50) of the corresponding printer (28). Is transmitted as radio waves. The radio waves on which the print and graphic data are superimposed are absorbed by the antenna (48) of the shared device (50) of the printer (28) and received by the transmission / reception circuit (24) in the reception mode.

The print / graphic data received by the transmission / reception circuit (24) is amplified and demodulated here.
The data is stored in the buffer memory (34) via the ART (18). The print and graphic data stored in the buffer memory (34) are processed by the CPU (32) to generate I / O data.
It is output from the / 0 port (30) and printed and plotted by the printer (28).

[0016]

Since the present invention is constructed as described above, it is possible to reduce the size and cost of the circuit.

[Brief description of the drawings]

FIG. 1 is a block circuit diagram of the present invention.

FIG. 2 is an explanatory block diagram showing an application example of the present invention.

FIG. 3 is a block diagram of a prior art.

[Explanation of symbols]

 Reference Signs List 2 amplifying circuit 4 amplifying circuit 6 modulating circuit 8 switching circuit 10 antenna 12 demodulating circuit 14 amplifying circuit 14a input terminal 14b output terminal 16 first switching circuit 16a contact 16b contact 16c contact 18 modulation circuit 20 antenna 22 second switching circuit 22a Contact 22b Contact 22b Contact 24 Demodulation circuit 26 Computer 28 Printer 30 I / O port 32 CPU 34 Memory 36 UART 38 Power supply circuit 40 Switching circuit 42 High-pass filter 44 Low-pass filter 46 AC adapter 48 Antenna 50 Wireless printer sharing device

Claims (1)

[Claims] In a transmission / reception circuit unit for a wireless device comprising a modulation circuit, a demodulation circuit, and an amplification circuit for amplifying a transmission and reception modulated signal, when transmitting,
Connects between the modulation circuit and the input terminal of the amplifier circuit and cuts off between the antenna and the input terminal of the amplifier circuit, and cuts off between the modulation circuit and the input terminal of the amplifier circuit during reception. And a first switching circuit that connects between the antenna and the amplifier circuit, and that, during transmission, cuts off between the demodulation circuit and the output terminal of the amplifier circuit and connects the antenna and the output terminal of the amplifier circuit. And a second switching circuit that connects between the demodulation circuit and the output terminal of the amplification circuit and disconnects between the antenna and the amplification circuit during reception. A transmission / reception circuit unit for a wireless device, which is also used for reception.