JPH05129983A - Radio communication equipment - Google Patents

Abstract

PURPOSE:To attain the talking with lots of unspecified users by implementing electric replacement control of a transmission reception frequency band together with the operation of a call request in the dialing and talking with respect to the transmission reception frequency band in the standby state or the called state. CONSTITUTION:A transmission signal from a VCO circuit (g) is sent to a power amplifier (n) by a switching circuit (m). The amplified transmission signal is sent to a BPFb2 by the switching circuit (m) and fed to an antenna (a). Moreover, a reception signal inputted from the antenna (a) and passing through the BPFb1 is fed to a reception amplifier (d) by a switching circuit (c) and amplified. The amplified reception signal is inputted to a mixer (h) and mixed with the output signal of a local oscillator (k) connecting to a switching circuit (j), converted into an intermediate frequency, and sent from a switching circuit (i) to a next-stage circuit. In this case, no power supply is supplied to a reception amplifier (o), a mixer (p) and a switching circuit (q) or the like at a frequency band f2 and isolation between the transmission signal output terminal of a power amplifier (n) and the input terminal of the reception amplifier (o) by the switching circuit (m) in the nonoperating state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a duplex type wireless communication device.

[0002]

2. Description of the Related Art In wireless communication devices, a specific low-power wireless communication device is widely used as a vehicle-mounted type or a portable type, especially for use in a duplex system. The duplex communication wireless communication device is capable of performing transmission and reception at the same time by separating the transmission frequency f1 and the reception frequency f2 at a certain constant interval (several MHz). Conventionally, when communication is performed by this method, the pair of wireless communication devices on this side and the other side have opposite relations between the transmission frequency and the reception frequency, so that simultaneous duplex communication is possible. Becomes That is, when the device on this side has the transmission frequency f1 and the reception frequency f2, the device on the communication side has the transmission frequency f2 and the reception frequency f1.

FIG. 2 shows a related circuit configuration of a radio communication apparatus according to a conventional duplex system, the contents of which will be described in detail with reference to the drawings. The receiving bandpass filter 2 and the transmitting bandpass filter 8 are branched and connected to the antenna 1, and form a duplexer there. The received signal from the antenna 1 is passed through the receiving bandpass filter 2 and the amplifier 3
Is amplified by, is input to the mixer 4, is mixed with the output of the local oscillator 5, and is converted into an intermediate frequency. It is to be noted that the voice paths up to that point are omitted as they are publicly known. Also,
For transmission, the output from the VCO 6 is amplified by the power amplifier 7, sent to the antenna 1 via the transmission bandpass filter 8, and the transmission signal is output from the antenna 1. The circuit configuration up to the VCO 6 is publicly known and will be omitted. The following points must be taken into consideration in the above circuit configuration. That is, the receiving bandpass filter 2 must have a characteristic having a sufficient amount of attenuation in the transmission frequency band so as not to be affected by its own transmission output. Further, the transmission bandpass filter 8 must have a characteristic of sufficiently attenuating the reception frequency band in the sideband of the transmission carrier.

Therefore, the frequency band that can be transmitted or received is determined by the characteristics of such a bandpass filter, and the device on the other end of the call must be a model in which the bandpass filters for transmission and reception are replaced. I won't. That is, two types of models as described above are required for a call, and when these two types of models are arranged for a large number of users, the parties to which calls can be made are naturally limited, and the number of calls is one-to-one. There is a problem that it is limited to things.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems and the like, and enables communication with users of wireless communication devices arranged in an unspecified large number. It is an object of the present invention to provide a duplex communication type wireless communication device capable of making the call only with one model.

[0006]

In order to achieve the above-mentioned object, a switching circuit for electrically controlling the connection between each bandpass filter and the transmission / reception circuit system by providing each transmission / reception circuit system with its own bandpass filter. The gist of the present invention is that the transmission / reception frequency band during the outgoing call is replaced electrically with the transmission / reception frequency band during the standby call or the called call along with the operation of the call request.

[0007]

With the above-mentioned structure, transmission / reception can be performed in any frequency band of duplex communication, and the transmission / reception frequency band can be electrically switched together with the operation of the call request.

[0008]

FIG. 1 is a circuit diagram showing an embodiment of the device of the present invention. An antenna a is branched and connected to a bandpass filter b1 of a frequency band f1 and a bandpass filter b2 of a frequency band f2. , There is a duplexer.

The band-pass filter b1 is connected as a branch connection through a switching circuit c, one of which is connected to a receiving circuit system such as a receiving amplifier d, a mixer h, a switching circuit i, and the other is a transmission power amplifier e and a switching circuit f. , V
It is connected to a transmission circuit system such as a CO circuit g to constitute a transmission / reception circuit of a frequency band f1 by switching. The bandpass filter b2 is connected as a branch connection through the switching circuit m, one of which is connected to the receiving circuit system such as the receiving amplifier o, the mixer p, and the switching circuit q, and the other is the transmission power amplifier n, the switching circuit f, and the VCO circuit. It is connected to a transmission circuit system such as g to configure a transmission / reception circuit of the frequency band f2 by switching.

In the device of the present invention, the transmission frequency band is f
1. When making a call with the reception frequency band as f2, V
The transmission signal of the CO circuit g is connected to the power amplifier e by the switching circuit f. The amplified transmission signal is sent to the bandpass filter b1 by the switching circuit c and supplied to the antenna a. Also, input from the antenna a,
The reception signal that has passed through the bandpass filter b2 is sent to the reception amplifier o by the switching circuit m and is amplified. The amplified received signal is input to the mixer p, mixed with the output signal of the local oscillator k connected by the switching circuit j, converted to an intermediate frequency, and sent from the switching circuit q to a known next-stage circuit (not shown). ..

At this time, power is not supplied to the receiving amplifier d, the mixer h, the switching circuit i, etc. on the frequency band f1 side, and the transmission signal output terminal of the power amplifier e is further operated by the switching circuit c in the non-operating state. And the isolation of the input end of the reception amplifier d is secured. Also, VC
The transmission signal of the O circuit g is not connected to the power amplifier n on the frequency band f2 side by the switching circuit f, the power amplifier n is not supplied with power and is in a non-operating state, and is further cut off by the switching circuit m. Isolation with the reception amplifier o is ensured.

As is clear from the above description, the reception sensitivity of the frequency band f2 is not affected by the output of the transmission signal of its frequency band f1.

Next, description will be given of a case where a call is made by the device of the present invention with the transmission frequency band f2 and the reception frequency band f1. The transmission signal of the VCO circuit g is sent to the power amplifier n by the switching circuit m. The amplified transmission signal is sent to the bandpass filter b2 by the switching circuit m.
To the antenna a. The received signal input from the antenna a and passed through the bandpass filter b1 is sent to the receiving amplifier d by the switching circuit c and is amplified. The amplified received signal is input to the mixer h, mixed with the output signal of the local oscillator k connected by the switching circuit j, converted to an intermediate frequency, and sent from the switching circuit i to a known next-stage circuit (not shown). ..

At this time, no power is supplied to the receiving amplifier o, the mixer p, the switching circuit q, etc. on the frequency band f2 side, and the transmitting circuit outputs the transmission signal of the power amplifier n by the switching circuit m in the non-operating state. Isolation between the end and the input end of the reception amplifier o is ensured. Also, VC
The transmission signal of the O circuit g is not connected to the power amplifier e on the frequency band f1 side by the switching circuit f, the power amplifier is not supplied with power, is in a non-operating state, and is cut off by the switching circuit c. Isolation with the amplifier d is ensured.

As is clear from the above, the reception sensitivity suppression of the frequency band f1 by the transmission signal output of its own frequency band f2 is not affected.

[0016]

As described above, the wireless communication device of the present invention enables transmission and reception in both frequency bands with one device in duplex communication, and the transmission and reception frequency during standby and called calls. The band and the transmission / reception frequency band at the time of the outgoing call can be electrically switched together with the outgoing call request of the user, and the duplex call can be performed by only one type of device. The user of the device of the present invention does not need to distinguish the devices and can talk with an unspecified number of parties, and since the transmission / reception frequency band at the time of standby and calling is defined in advance, the same frequency is used. It will be possible to contact all of the standby stations at the same time. Also, for the producer and seller of the device, since only one model is required, a great effect can be expected in terms of its management.

[Brief description of drawings]

FIG. 1 is a circuit configuration diagram showing a device of the present invention.

FIG. 2 is a related circuit diagram of a wireless communication device according to a conventional duplex system.

[Explanation of symbols]

 a antenna b1 band pass filter of frequency band f1 b2 band pass filter of frequency band f2 c switching circuit d receiving amplifier e power amplifier f switching circuit g VCO circuit h mixer i switching circuit j switching circuit k local oscillator m switching circuit n power Amplifier o Receiver amplifier p Mixer q Switching circuit

Claims (1)

[Claims] 1. In wireless transmission / reception, each transmission / reception circuit system is provided with its own bandpass filter, and a switching circuit electrically controlling the connection between each bandpass filter and the transmission / reception circuit system is provided. A wireless communication device, characterized in that a transmission / reception frequency band during a call is electrically controlled with a call request operation with respect to a transmission / reception frequency band during a call.