JPH0738489A - Digital cordless telephone set - Google Patents

Abstract

PURPOSE:To secure the excellent reception performance by providing with two transmission reception antennas to a master set and providing with a piece of transmission reception antenna and a piece of reception dedicated antenna to a slave set. CONSTITUTION:Two transmission reception antennas are provided to a master set, and a piece of transmission reception antenna 51 and a piece of reception dedicated antenna 52 are provided to a slave set. Suppose that the slave set is in the standby state to receive a control signal sent from the master set. In the case either of the two transmission reception antennas is used for the antenna used to send a control signal from the master set. On the other hand, the reception by the antennas 51, 52 on the slave set is made selectively and selected diversity communication is made for one antenna enabling better reception. When a connection control signal is sent from the slave set, the transmission reception antenna 51 is used. When the master set receives the connection control signal, the master set selects an antenna for enabling better reception by using selectively the two transmission reception antennas.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital cordless telephone device in which communication between a master unit and a slave unit is performed by transmitting / receiving digital data.

[0002]

2. Description of the Related Art A digital cordless telephone system is constructed, for example, as shown in FIG. In FIG. 4, reference numeral 1 denotes a base unit serving as a base station, and the base unit 1 is connected to a telephone line and includes two antennas 1a and 1b for communicating with a handset. A plurality of (three in this case) slaves capable of communicating with the master 1 are prepared. That is, the slaves 2, 3, 4 are prepared, and the antennas 2a, 3a, 4a are attached to the slaves 2, 3, 4 respectively.
Wireless transmission is performed between the antenna 1a or 1b of the master device 1 and the antennas 2a, 3a, 4a of the slave devices 2, 3, and 4.

When a call is made with each of the slave units 2, 3 and 4 to the master unit 1 (or the other party connected to the master unit 1 via a telephone line), a connection control signal of a predetermined format is transmitted to the master unit 1.
Then, the voice data converted into digital data is transmitted to the base unit 1 in a time division manner with the base unit 1 to make a call.

In this case, the base unit 1 has two antennas 1
Since a and 1b are prepared, these two antennas 1
By selecting and using an antenna that can satisfactorily communicate with the child device side among a and 1b, so-called space diversity communication is performed and communication performance can be improved.

In such a digital cordless telephone device, transmission and reception are performed at the same frequency, and so-called ping-pong transmission is performed in a TDD system (time division duplex system) or a TDMA / TDD system (time division multiple access / time division). There are some that are adopted.

That is, in the case of the TDD system, for example, A in FIG.
, One channel (frequency) is temporally divided into a transmission slot T and a reception slot R, these slots T and R are alternately repeated, and a guard is provided between these slots T and R. A time (not shown) is provided. In this case, for example, each slot T and R is set to 1 msec and the guard time is set to several tens of microseconds. And
The mobile phone (slave unit) communicates with the base station (parent device) in the transmission slot T and receives from the base station in the reception slot R.

In the case of the TDMA / TDD system,
As shown in FIG. 5B, a transmission slot T and a reception slot R in one channel are used for communication between one slave unit and the master unit.
, Are used only once every several cycles, and other transmission slots T and reception slots R in the same channel are used for communication between another slave unit and the master unit, and a plurality of units are used for one channel. It is multiplexed so that communication between communication devices can be performed.
By being multiplexed in this way, the frequency band prepared for the cordless telephone can be used efficiently.

Next, a conventional configuration of a base unit of a digital cordless telephone device for performing such communication will be described with reference to FIG. In FIG. 6, reference numerals 11 and 12 denote antennas for transmitting and receiving, and both antennas 11 and 12 are first antennas.
Fixed switch 13a of one and the other of the changeover switch 13 of
Connect to 13b. Then, the first changeover switch 1
The movable contact 13m of No. 3 is connected to the movable contact 14m of the second changeover switch 14, and one fixed contact 14a of the second changeover switch 14 is connected to the receiving unit 21.

Then, in the receiving section 21, the antenna 11,
A predetermined frequency band is received from the reception signal supplied from the 12 side, the processed reception signal is supplied to the modulation / demodulation unit 23, and the reception signal is demodulated. Then, the demodulated signal is supplied to the communication control unit 24. In addition, the data regarding the reception field strength (RSSI) in the reception unit 21 is stored in the communication control unit 2
Supply to 4.

Further, the transmission signal output from the communication control unit 24 is modulated for transmission by the modulation / demodulation unit 23, and the modulated transmission signal is transmitted by the transmission unit 22. Then, the processed transmission signal is supplied to the other fixed contact 14b of the second changeover switch 14, and the transmission signal is supplied to the antennas 11 and 12 via the changeover switches 14 and 13.

Then, the communication control unit 24 performs various communication controls such as setting of a channel for communication with each slave unit and control of transmission / reception timing, and the above-described first and second communication. The changeover switches 13 and 14 are controlled so that the first changeover switch 13 selects an antenna for transmission and reception, and the second changeover switch 14 is selected.
Switch between transmission and reception with.

Further, the communication control unit 24 is provided with an ADPC.
The M codec unit 25 is connected, and the audio data (ADPCM signal) included in the received signal is converted into an analog audio signal by the ADPCM codec unit 25 and supplied to the line interface unit 26 side, and at the same time, the line interface unit 26 side. The analog audio signal supplied from
It is converted into a PCM signal and supplied to the communication controller 24.

The line interface unit 26 has a terminal 27 for connecting to a telephone line, and is connected to the telephone office side via this terminal 27. A handset 28 and a key input unit 29 are connected to the line interface unit 26, and a microphone and a speaker in the handset 28 can be used to make an external call and an internal call and to supply from the key input unit 29. A call or the like is controlled according to the key operation information.

Next, the structure of the conventional slave unit will be described with reference to FIG. In FIG. 7, reference numeral 31 denotes an antenna, which is connected to the movable contact 32m of the changeover switch 32. Then, the reception signal obtained at one fixed contact 32a of the changeover switch 32 is supplied to the reception unit 33, and the reception unit 33 receives and processes a predetermined frequency band from the reception signal supplied from the antenna 31 side. The received signal thus obtained is supplied to the modulation / demodulation unit 35 to demodulate the received signal. Then, the demodulated signal is supplied to the communication control unit 36.

Further, the transmission signal output from the communication control unit 36 is modulated by the modulation / demodulation unit 35 for transmission, and the modulated transmission signal is transmitted by the transmission unit 34. Then, the processed transmission signal is sent to the other fixed contact 32b of the changeover switch 14.
And the transmission signal is supplied to the antenna 31 side via the changeover switch 32.

The communication control unit 36 performs various communication controls such as setting a call channel and controlling transmission / reception timing, and controls switching of the changeover switch 32 to switch between transmission and reception.

Further, the communication control unit 36 has an ADPC
The M codec unit 37 is connected, and the audio data (ADPCM signal) included in the received signal is converted into an analog audio signal by the ADPCM codec unit 37 and the speaker 38 is used.
The analog audio signal supplied from the microphone 39 is converted into an ADPCM signal and supplied to the communication control unit 36.

In addition, the ADPCM codec section 37 includes
The key input unit 41 and the display unit 42 are connected via the man-machine interface unit 40, and the operation information of the key input unit 41 is the man-machine interface unit 40, AD.
Display information, which is supplied from the communication control unit 36 to the display unit 42 while being supplied to the communication control unit 36 via the PCM codec unit 37, is transmitted via the ADPCM codec unit 37 and the man-machine interface unit 40. Supplied.

When an extension call or an outside call from the slave unit is performed between the slave unit and the master unit, the slave unit transmits a connection request signal to the master unit to confirm that the master unit has a connection request. After notifying, perform processing to synchronize the slave unit and the master unit, and then use the predetermined slot in the communication channel based on the instruction from the control signal from the master unit to connect the slave unit and the master unit. Initiate communication for calls between. When calling a child device from the parent device, a control signal is transmitted from the parent device to the child device to call the corresponding child device. For this reason, each slave unit intermittently receives only the control signal transmitted from the master unit when in the standby state.

When communication is performed in this way,
Changeover switch 13 for two antennas 11 and 12 in the base unit
The switching is performed based on the received electric field strength data supplied to the communication control unit 24. That is, for example, first, the movable contact 13m of the first changeover switch 13 is connected to one fixed contact 13a, and the signal received by the antenna 11 is supplied to the receiving unit 21 for reception processing. And
When the communication control unit 24 determines that the reception electric field strength of the signal transmitted from the slave unit at this time is equal to or higher than a predetermined threshold level sufficient for reception, the antenna 11 performs transmission and reception.

When the communication control section 24 determines that it is difficult to perform good reception when the received electric field strength of the signal transmitted from the slave unit is below the threshold level, it is possible to move the first changeover switch 13. The contact 13m is switched to the other fixed contact 13b side, and the signal received by the antenna 12 is supplied to the receiving unit 21 for reception processing. Then, when the communication control unit 24 determines that the received electric field strength of the signal transmitted from the slave unit at this time is equal to or higher than the threshold level sufficient for reception, the antenna 12
To perform transmission and reception.

When the reception electric field strength at the time of reception using the antenna 12 becomes lower than the threshold level, the antenna 12 is switched again to the antenna 11 side.

In this way, the antenna 11 or 12 that can perform good reception is switched to perform space diversity communication for transmission and reception. In this case, the TDMA / TDD to which this cordless telephone is applied
In the case of the TDD method and the TDD method, since transmission and reception are performed at the same frequency, if the reception at the master unit is good, the transmission from the master unit will also be performed under the same conditions, so that it is possible to perform well with the same antenna. By providing only two antennas on the base unit side, good space diversity communication can be performed in both cases of downlink communication from the base unit and uplink communication to the base unit.

[0024]

However, if two antennas are provided in the base unit for performing such diversity communication, the reception unit 21 and the transmission unit 22 of the base unit,
Two antenna changeover switches 13 and 14 are inserted in series between the antennas 11 and 12, resulting in a large loss of transmission signals and reception signals. That is, it is necessary to increase the output of the power amplifier in the transmission unit 22 by the amount of the insertion loss due to the changeover switches 13 and 14, and the load of the power amplifier is large and the received signal level supplied to the reception unit 21 is also increased. So lower
Receiving ability will decrease.

Further, if two antennas are provided only in the master unit as described above, only one of the antennas is used when only transmitting the control signal from the master unit to each slave unit. There was an inconvenience that communication was not possible. In this case, if each handset also has two antennas,
Diversity communication is possible even when the control signal is received on the slave side. However, as in the case of the master unit described above, the antenna switching switches are connected in series in two stages, and this switching is performed. The transmission / reception performance will be reduced by the amount of switch insertion loss.

Further, if two antennas are provided only in the master unit, when a call between the slave units is performed between the two slave units, the communication of the diversity system cannot be performed and the call between the slave units is not possible. There is a disadvantage that the communication performance at that time is lower than that in the case of performing communication with the base unit.

In view of these points, the present invention is to enable diversity communication efficiently and favorably in any case in this type of cordless telephone device.

[0028]

DISCLOSURE OF THE INVENTION The present invention provides a digital cordless telephone apparatus which is composed of a base unit and a handset unit, and which carries out a telephone call by wirelessly transmitting digital data between the base unit and the handset unit. The base unit is provided with two transmitting / receiving antennas, and the slave unit is provided with one transmitting / receiving antenna and one receiving-only antenna.

Further, in this case, when the slave unit is in the standby state, the control signal is transmitted from the master unit from only one of the two transmitting / receiving antennas, and at the same time, in the slave unit. This control signal is received by selectively using one of the transmitting and receiving antennas and the one receiving-only antenna that can receive well.

Further, in this case, when the connection request signal is transmitted between the master unit and the slave unit, the transmission of the connection request signal from the master unit is favorably received by the two transmitting / receiving antennas. In addition to selectively using the available antenna, the slave unit receives the connection request signal by using only one of the transmitting / receiving antenna and the receiving antenna. It is the one that is supposed to be used.

Further, in this case, when transmitting a call signal between the master unit and the slave unit, the antenna which can favorably receive the transmission / reception of the master unit from the two transmitting / receiving antennas is selected. In addition to the above, the transmission / reception in the slave unit is performed using only one transmission / reception antenna.

Further, in this case, when a direct call is made between a plurality of slave units, transmission from each slave unit is performed using the transmitting / receiving antenna and reception at each slave unit is performed by one line. Among the transmission / reception antenna and the one reception-only antenna, an antenna capable of excellent reception is selectively used.

Further, the present invention comprises a master unit and a slave unit,
In the digital cordless telephone device for making a call by wirelessly transmitting digital data between the master unit and the slave unit,
The parent device is provided with one transmitting / receiving antenna and one receiving antenna, and the child device is provided with one transmitting / receiving antenna and one receiving antenna.

Further, in these cases, when the slave unit communicates with the public base station, only one transmitting / receiving antenna is used as the transmitting / receiving antenna of this slave unit.

[0035]

According to the present invention, the base unit is provided with two transmitting / receiving antennas, and the slave unit is provided with one transmitting / receiving antenna.
By providing the book-only reception antenna, diversity communication can be performed by switching the reception antenna to a better one even when reception is performed on the slave unit side.

According to the present invention, the base unit is provided with one transmission / reception antenna and one reception-only antenna, and the sub-unit is provided with one transmission / reception antenna and one reception-only antenna. , Even when receiving on the side of the handset, by switching the receiving antenna to the better one, diversity communication can be performed and the antenna switch of the base unit and the handset can be made the same configuration, sharing the parts. Can be realized.

[0037]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A slave unit according to an embodiment of the present invention will now be described with reference to FIG.
Will be described with reference to. In FIG. 1, parts corresponding to those of FIG. 7 shown as a conventional example are denoted by the same reference numerals, and detailed description thereof will be omitted.

In this example, TDMA is performed as in the conventional example.
It is applied to a digital cordless telephone device of the / TDD system, and is configured as shown in FIG. That is, in FIG. 1, reference numeral 51 indicates a transmitting / receiving antenna, and 52 indicates a receiving-only antenna. Then, the transmission / reception antenna 51 is connected to the movable contact 53m of the transmission / reception changeover switch 53, and one fixed contact 53a of the transmission / reception changeover switch 53 is connected to one fixed contact 54a of the reception antenna changeover switch 54. Then, the reception-only antenna 52 is connected to the other fixed contact 54b of the reception antenna changeover switch 54. Then, the reception signal obtained at the movable contact 54m of the reception antenna changeover switch 54 is supplied to the reception unit 33. Further, the transmission signal output by the transmission unit 34 is supplied to the other fixed contact 53b of the transmission / reception changeover switch 53.

Then, the communication control section 36 controls switching between the transmission / reception changeover switch 53 and the reception antenna changeover switch 54. In this case, the communication control unit 36 of this example is supplied with data on the electric field strength received by the receiving unit 33, and when the electric field strength received falls below a predetermined threshold level, the receiving antenna is switched. The switch 54 is switched. Further, the transmission / reception changeover switch 53 is switched in association with the switching between transmission and reception by this slave unit.

Other parts are constructed in the same manner as the slave unit shown in FIG. 7 as a conventional example.

Next, the communication state using the child device configured as described above will be described. Here, it is assumed that communication is performed with the parent device shown in FIG. 6 described in the conventional example. At this time, the parent device has two transmitting / receiving antennas 11 and 12, and the child device has one transmitting / receiving antenna 51 and one receiving antenna 52.

First, it is assumed that the child device is in a standby state in which it intermittently receives the control signal transmitted from the parent device. At this time, only one of the two transmitting / receiving antennas 11 and 12 is used as the antenna used for transmitting the control signal from the master unit, and the changeover switch 13 is fixed. Then, the control signal transmitted from the antenna 11 or 12 is intermittently received by the slave unit.
At this time, the communication control section 36 determines the received electric field strength of the control signal, and when it is determined that the received electric field strength is below a predetermined threshold level, the receiving antenna changeover switch 54 is switched. Therefore, by switching the selector switch 54, reception using the transmitting / receiving antenna 51 and reception using the reception-only antenna 52 are selectively performed,
Diversity communication is performed in which one that can receive better is selected. It should be noted that the transmission / reception change-over switch 53 must be the movable contact 53 at the timing of receiving the control signal.
m is connected to one fixed contact 53a.

Next, a case will be described in which a calling operation is performed on the slave unit side and a connection request signal is transmitted from the slave unit to the master unit. At this time, under the control of the communication control unit 36, the movable contact 54m of the reception antenna changeover switch 54 of the slave unit is connected to one fixed contact 54a, and the antenna used for reception is fixed to the transmission / reception antenna 51. When the connection control signal is transmitted from the slave unit, the movable contact 53m of the transmission / reception changeover switch 53 is set to the other fixed contact 53b.
The connection request signal is transmitted using the transmitting / receiving antenna 51.

The reception of this connection request signal on the master unit side is performed by selectively using the two transmitting / receiving antennas 11 and 12 and using the antenna which can receive well. Diversity communication is performed by switching the side antenna. In this case, the transmission of the control signal including the data for permitting the connection, which is performed subsequent to the reception of the connection request signal at the base unit, is performed by the antenna 1 that has successfully received the connection request signal.
1 or 12 is used, and both communication between the master unit and the slave unit is performed by the diversity method.

Next, when the slave unit receives the control signal in the standby state and talks with the master unit (including the case where the slave unit talks with an outside line through the master unit), or the slave unit A case will be described in which a call is made based on the control of the base unit after the connection request signal is transmitted from the base unit. When making a call with the base unit, the movable contact 54m of the reception antenna changeover switch 54 of the handset is maintained in a state of being connected to one fixed contact 54a, and transmission and reception are performed using only the transmitting / receiving antenna 51. Is performed in a time-sharing manner, and transmission and reception on the communication channel are alternately performed. Then, on the base unit side, two antennas 11 and 12 are switched based on the received electric field strength as in the conventional case, and diversity communication is performed in which transmission and reception are performed using the antenna 11 or 12 that can receive well.

Next, description will be given of a case where a telephone call between two handset units is performed. At this time, first, connection control is performed between the caller-side cordless handset and the call-receiving side cordless handset, and then communication between cordless handsets is started by transmission and reception using the call channel. From the time to the time of making a call, at any timing in which the respective slaves receive in any state, the receiving antenna selector switch 54 is switched to the one that can receive well based on the received electric field strength, and the antenna used for reception is the antenna. Diversity communication for switching between 51 and 52 is performed. However, for transmission, the transmitting / receiving antenna 5
Only one can be used, so antenna 5
Use 1.

By using the slave unit of this example as described above,
In either case, good diversity communication is performed.
That is, in the case of receiving a signal from the base unit or the like, the antenna used for reception can be switched by switching the reception antenna changeover switch 54, and diversity reception can be performed in which the reception antenna is selected as good. In particular, diversity communication is performed even during standby when intermittently receiving the control signal transmitted from the master unit or when talking between slave units, and good transmission with reduced reception errors due to fading can be performed. Like

Since the receiving-only antenna 52 is connected to the receiving unit 33 via only one antenna changeover switch 54, at least when the antenna 52 is used for reception, the antenna changeover switch is used. The reception signal can be received with a small insertion loss, and good reception characteristics can be secured compared to the case where two transmitting and receiving antennas are provided in the slave unit, and the load on the power amplifier and the like that processes the reception signal. Can be reduced.

Next, the configuration of the base unit of the cordless telephone of this example will be described with reference to FIG. In FIG. 2, parts corresponding to those of FIG. 6 shown as a conventional example are denoted by the same reference numerals, and detailed description thereof will be omitted.

In this example, the configuration of the antenna switching device is the same as that of the above-mentioned slave unit, and is configured as shown in FIG. That is, in FIG. 2, 61 indicates a transmitting / receiving antenna, and 62 indicates a receiving-only antenna. And
The transmission / reception antenna 61 is connected to the movable contact 63m of the transmission / reception changeover switch 63, and one fixed contact 63a of the transmission / reception changeover switch 63 is connected to the reception antenna changeover switch 6
4 is connected to one fixed contact 64a. Then, the reception-only antenna 62 is connected to the other fixed contact 64b of the reception antenna changeover switch 64. Then, the reception signal obtained at the movable contact 64 m of the reception antenna changeover switch 64 is supplied to the reception unit 21. Further, the transmission signal output from the transmission unit 22 is supplied to the other fixed contact 63b of the transmission / reception changeover switch 63.

Then, the communication control section 24 controls switching between the transmission / reception changeover switch 63 and the reception antenna changeover switch 64. In this case, the communication control unit 24 of this example is supplied with data regarding the electric field intensity received by the receiving unit 21, and when the electric field intensity received falls below a predetermined threshold level, the receiving antenna is switched. The switch 64 is switched. Further, the transmission / reception changeover switch 63 is switched in association with the switching between transmission and reception by the master unit.

Other parts are constructed in the same manner as the base unit shown in FIG. 6 as a conventional example.

Next, the communication state of the cordless telephone using the master unit of the example shown in FIG. 2 and the slave unit shown in FIG. 1 will be described. At this time, one transmission / reception antenna 61 and one reception-only antenna 62 are prepared in the master unit, and one transmission / reception antenna 51 and one reception-only antenna 52 are prepared in the slave unit. Will be there.

First, it is assumed that the slave unit is in a standby state in which it intermittently receives the control signal transmitted from the master unit. At this time, the transmitting / receiving antenna 61 is the only antenna used for transmitting the control signal from the master unit. The control signal transmitted from the antenna 61 is intermittently received by the slave unit. At this time, the communication control unit 36.
When the received electric field strength of the control signal is judged with and it is judged that the received electric field strength is below a predetermined threshold level,
The receiving antenna selector switch 54 is switched. Therefore, by switching the changeover switch 54, the reception using the transmitting / receiving antenna 51 and the reception using the reception-only antenna 52 are selectively performed, and diversity communication is performed in which the better reception is selected.

Next, a case will be described in which a calling operation is performed on the slave unit side and a connection request signal is transmitted from the slave unit to the master unit. At this time, under the control of the communication control unit 36, the movable contact 54m of the reception antenna changeover switch 54 of the slave unit is connected to one fixed contact 54a, and the antenna used for reception is fixed to the transmission / reception antenna 51. When the connection control signal is transmitted from the slave unit, the movable contact 53m of the transmission / reception changeover switch 53 is set to the other fixed contact 53b.
The connection request signal is transmitted using the transmitting / receiving antenna 51.

The reception of this connection request signal on the master unit side can be favorably received by selectively using the transmission / reception antenna 61 and the reception-only antenna 62 by switching the reception antenna changeover switch 64. One antenna is used to perform diversity communication by switching the antenna on the master side. However, the transmission of the control signal including the data for permitting the connection, which is performed subsequent to the reception of the connection request signal in the parent device, uses the transmission / reception antenna 61 regardless of which antenna receives the connection request signal. To do.

Next, when the slave unit receives a control signal in a standby state and talks with the master unit (including a case where the slave unit talks with an outside line through the master unit), or the slave unit A case will be described in which a call is made based on the control of the base unit after the connection request signal is transmitted from the base unit. When making a call with the base unit, by switching the reception antenna selector switch 54 of the handset, the transmitting / receiving antenna 51 and the reception-only antenna 52 are selectively used, and the antenna that can receive favorably is used. Then, diversity communication is performed by switching the receiving antenna. And on the base unit side,
The transmission / reception antenna 61 and the reception-only antenna 62 are selectively used, and the antenna with the better reception is used to perform diversity communication by switching the reception antenna.

In this way, the two-way diversity communication is realized by performing the process of switching the receiving antennas of both the master unit and the slave unit to the one that can receive well during a call.

As described above, even when the parent device and the child device of this example are used in combination, good diversity communication is performed in any case, and good transmission with reduced reception errors due to fading is possible. Become. In this case, the configuration of the antenna switching device (switches 63, 64) of the parent device and the configuration of the antenna switching device (switches 53, 54) of the child device are the same, and the antennas of the parent device and the child device are the same. The switch can be shared, and the manufacturing cost of the cordless telephone can be reduced.

Further, in this example, since the reception-only antenna 62 is connected to the reception unit 21 via only one antenna changeover switch 64 on the base unit side as well, reception is performed using at least this antenna 62. In this case, the reception signal can be received with a small insertion loss due to the antenna changeover switch, and good reception characteristics can be ensured as compared with the case where two transmitting and receiving antennas are provided in the base unit, and the reception signal is correspondingly larger. Can reduce the load on the power amplifier etc.

The above-described antenna switching state during each communication is a case where a master unit and a slave unit combined as a cordless telephone are used, and many public base stations installed outdoors as a master unit are used. When used as a so-called personal handy phone that communicates between this public base station and the handset, it is assumed that diversity communication is performed using multiple antennas on the base station side. It For this reason, when the mobile phone is used as this personal handy phone, the movable contact 54m of the receiving antenna changeover switch 54 is kept connected to one fixed contact 54a in the slave unit, and only the transmitting / receiving antenna 51 is used. Good communication can be performed by receiving the control signal and performing communication on the communication channel.

[0062]

According to the present invention, two transmitter / receiver antennas are provided in the master unit, and one transmitter / receiver antenna and one receive-only antenna are provided in the slave unit. Even at the time of reception, diversity communication is performed in which the reception antenna is switched to a better one for reception, and good reception performance is ensured.

In this case, when the slave unit is in the standby state, the control signal is transmitted from the master unit from only one of the two transmitting / receiving antennas, and
The control signal is received by the slave unit by selectively using an antenna that can receive favorably between one transmitting / receiving antenna and one receiving-only antenna, and the control signal is transmitted from the master unit. It becomes possible for the slave unit to satisfactorily receive the control signal that is generated by the diversity communication.

Further, in this case, when the connection request signal is transmitted between the master unit and the slave unit, the transmission of the connection request signal from the master unit is favorably received within the two transmitting / receiving antennas. In addition to selectively using the available antenna, the slave unit receives the connection request signal by using only one of the transmitting / receiving antenna and the receiving antenna. By using this, the connection request signal can be transmitted by good diversity communication only by controlling the antenna switching on the master side.

Further, in this case, when transmitting a call signal between the master unit and the slave unit, the antenna which can favorably receive the transmission / reception of the master unit from the two transmitting / receiving antennas is selected. In addition to the above, the transmission and reception with the slave unit is performed by using only one transmitting and receiving antenna.
For bidirectional transmission of call signals, good diversity communication can be achieved only by controlling the antenna switching on the master side.

Further, in this case, when a direct call is made between a plurality of slave units, transmission from each slave unit is performed using the transmitting / receiving antenna, and reception at each slave unit is performed by one line. By selectively using the antenna that can receive well between the transmitting / receiving antenna and the one receiving antenna, the direct communication between the handset units can be performed by good diversity communication.

According to the present invention, the base unit is provided with one transmission / reception antenna and one reception-only antenna, and the sub-unit is provided with one transmission / reception antenna and one reception-only antenna. , Even when receiving on the side of the handset, by switching the receiving antenna to the better one, diversity communication can be performed and the antenna switch of the base unit and the handset can be made the same configuration, sharing the parts. The digital cordless telephone can be configured at low cost.

Further, in these cases, when the slave unit communicates with the public base station, only one transmitting / receiving antenna is used as the transmitting / receiving antenna of this slave unit. Diversity communication can be stably performed by switching the antenna on the station side.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a child device according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a parent device according to an embodiment.

FIG. 3 is an explanatory diagram showing a control signal according to an embodiment.

FIG. 4 is a configuration diagram showing a system configuration of a cordless telephone device.

FIG. 5 is a configuration diagram showing a communication system.

FIG. 6 is a configuration diagram of a base unit of a conventional digital cordless telephone.

FIG. 7 is a configuration diagram of a slave unit of a conventional digital cordless telephone.

[Explanation of symbols]

 51,61 Transmitting / receiving antenna 52,62 Receiving antenna 53,63 Transmission / reception selector switch 54,64 Reception antenna selector switch

Claims (7)

[Claims] 1. A digital cordless telephone apparatus comprising a base unit and a handset unit, which performs wireless communication of digital data between the base unit and the handset unit to make a call. A digital cordless telephone device in which an antenna for reception is provided, and at the same time, one transmission / reception antenna and one reception-only antenna are provided in the slave unit. 2. When the slave unit is in a standby state, the control signal is transmitted from the master unit from only one of the two transmitting and receiving antennas, and the control signal is transmitted from the slave unit. 2. The reception of the signal is performed by selectively using an antenna that can be favorably received from one transmission / reception antenna and one reception-only antenna.
The described digital cordless telephone device. 3. An antenna which, when transmitting a connection request signal between a master unit and a slave unit, can favorably receive the transmission of the connection request signal from the master unit from the two transmitting / receiving antennas. And the reception of the connection request signal at the slave unit is performed by using only one of the transmitting / receiving antenna and the receiving-only antenna. The digital cordless telephone device according to claim 1, wherein 4. When transmitting a call signal between a base unit and a handset, an antenna that can receive favorably among the two transmitting and receiving antennas is selectively used for transmitting and receiving by the base unit. The digital cordless telephone device according to claim 1, wherein the transmission and reception are performed by the slave unit by using only one transmission and reception antenna. 5. When making a direct call between a plurality of cordless handsets, transmission from each cordless handset is performed using a transmitting / receiving antenna, and reception by each cordless handset is performed by one transmitter / receiver. 2. The digital cordless telephone device according to claim 1, wherein an antenna that can receive well is selectively used from among the antenna and one receiving-only antenna. 6. A digital cordless telephone device comprising a base unit and a handset, and performing a wireless communication of digital data between the base unit and the handset, wherein one transmission / reception is performed by the base unit. A digital cordless telephone device, in which an antenna for reception and one reception-only antenna are provided, and at the same time a transmission / reception antenna and a reception-only antenna are provided in the slave unit. 7. When communicating the slave unit with a public base station,
7. The digital cordless telephone device according to claim 1, wherein only one transmitting / receiving antenna is used as the transmitting / receiving antenna of the slave unit.