JP3355410B2 - Wireless transceiver - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio transceiver such as a transceiver having a duplex circuit capable of two-way communication or simultaneous communication.

[0002]

2. Description of the Related Art As is well known, portable wireless transceivers such as transceivers have recently become very performant.
Also, the size and weight have been reduced. Under these circumstances, today, this kind of radio is widely used by people for various purposes, such as various jobs and leisure activities, and furthermore, a variety of radios are available for various uses. Functionalization is desired.

[0003] By the way, when a transceiver is viewed from the viewpoint of functionality, a so-called simplex system in which communication is performed by switching between transmission and reception when making a call has conventionally been generally used. Recently, a so-called duplex system capable of simultaneously performing both transmission and reception, such as a telephone, or a system incorporating both a simplex and a duplex system has been manufactured.

In such a duplex transceiver t, various filters are conventionally used for a duplex circuit d provided between an antenna a and a transmission circuit b and a reception circuit c as shown in FIG. ing. This allows you to distinguish between transmitted and received signals of different frequencies,
We are communicating two-way simultaneous calls.

[0005]

However, in the case of a filter, if the frequencies of the transmission and reception signals are close to each other, a part of both the transmission and reception frequency bands overlaps due to the characteristics, so that interference is likely to occur. There were difficulties.

In order to solve such a problem, if a filter circuit is assembled from individual components without using a commercially available unit, the circuit configuration becomes inevitably large.
Therefore, it was not suitable for small-sized equipment.

[0007] As shown in FIG. 4, there is also a type in which a duplex circuit e is configured by a circulator system. In this case, the frequency band is fixed to a specific frequency (for example, 800 MHz), and the selectivity of transmission / reception signals is selected. It is difficult to apply to transceivers and the like from the viewpoints of function and size.

[0008]

SUMMARY OF THE INVENTION Accordingly, the present invention has been made in view of the above points, and has a simple circuit configuration, is less likely to cause interference, and has a radio transceiver having a duplex circuit effective for downsizing equipment. The purpose is to provide a machine.

[0009]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a radio transceiver having a duplex circuit which enables simultaneous transmission and reception with one antenna, wherein the duplex circuit has a primary circuit. The antenna is formed on the side, and the receiving circuit and the transmitting circuit are formed on the secondary side by transformer coupling connected to different terminals.

[0010]

With the above arrangement, when performing simultaneous two-way communication of transmission and reception, the reception signals received from the antenna are inverted on the secondary side of the duplex circuit and input to the reception circuit. On the other hand, the transmission signals from the transmission circuit have opposite phases to the reception signals on both the secondary side and the primary side of the duplex circuit. Therefore, no interference occurs even when the signal frequencies of transmission and reception are close to each other.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A case where the embodiment of the present invention is applied to a general transceiver will be described below with reference to the drawings.

As shown in the block diagram of FIG. 1, a transceiver T includes an antenna 1 and a receiving circuit 2 connected thereto.
A duplex circuit 4 is provided between the transmission circuit 3 and the transmission circuit 3, and the layout of each circuit is the same as that of the conventional circuit.

The duplex circuit 4 has
As shown in FIG. 2, the circuit is mainly composed of a transformer having intermediate terminals 7 and 8 on the primary side 5 and the secondary side 6, respectively.

One of the primary sides 5 of the duplex circuit 4 has an antenna terminal 9 connected to the antenna 1, and the other has a ground terminal 10 connected to the ground.
have. One of the secondary sides 6 has a receiving terminal 11 connected to the receiving circuit 2, and the other has a transmitting terminal 12 connected to the transmitting circuit 3. The intermediate terminals 7, 8 of the primary side 5 and the secondary side 6 are connected to ground via a common capacitor 13. In this case, the magnitudes of the inductances of the primary side 5 and the secondary side 6 are appropriately set according to the frequency of the transmission / reception signals to be used. Also,
The capacitance of the capacitor 13 is optimally about 1 to 10 pF.

With this configuration, in the case of simultaneous transmission and reception, when a reception signal of, for example, 421 MHz enters the duplex circuit 4 from the antenna 1, the reception signal is inverted on the secondary side 6. Then, it is received by the receiving circuit 2.

When transmission signals of 441 MHz are sent from the transmission circuit 3 to the duplex circuit 4 at the same time,
On the primary side 5 it reverses and this is transmitted via the antenna 1.

As described above, even if the transmission and reception signals are close to each other, the phases or polarities of the respective signals on the primary side 5 and the secondary side 6 of the duplex circuit 4 are reversed, so that interference is caused. It can be separated without performing.

[0018]

As described above, since the radio transceiver according to the present invention has the duplex circuit formed by the transformer coupling mainly composed of the coil, the phases of the transmission signal and the reception signal are different from those of the primary side of the duplex circuit. Since the transmission and reception frequencies are reversed on the secondary side, no interference occurs even if both the transmitting and receiving frequencies are close to each other. Further, compared to a conventional duplex circuit constituted by a filter, the number of parts can be reduced, so that the circuit configuration can be simplified, and therefore, there is an advantage that it is extremely effective for downsizing of equipment.

[Brief description of the drawings]

FIG. 1 is a block diagram mainly showing a duplex system of a wireless transceiver according to the present invention.

FIG. 2 is a circuit diagram showing a basic configuration of the duplex circuit.

FIG. 3 is a block diagram mainly showing a conventional duplex system of a wireless transceiver.

FIG. 4 is a block diagram showing a conventional duplex system.

[Explanation of symbols]

 1 Antenna 2 Receiving circuit 3 Transmitting circuit 4 Duplex circuit 5 Primary 6 Secondary 7 Secondary 7 8 Intermediate terminal 9 Antenna terminal 10 Earth terminal 11 Reception terminal 12 Transmission terminal 13 Capacitor T Capacitor T Transceiver

Claims (1)

(57) [Claims] 1. A wireless transceiver having a duplex circuit that enables simultaneous transmission and reception with one antenna, wherein the duplex circuit has the antenna on the primary side and the reception circuit and the transmission circuit on the secondary side. DOO constituted by transformer coupling connected to each other terminals, the de
The duplex circuit has a primary side and a secondary side of the transformer.
Middle connected to ground through a common capacitor on the side
A wireless transceiver having a terminal .