JPH0634488B2 - Wireless telephone - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to a radiotelephone device having an improved method for determining the state of a radio line.

[Technical background of the invention]

For example, in a wireless telephone device called a cordless telephone, since a connection device and a wireless telephone are connected by a wireless line, the state of the wireless line is constantly monitored during a call and desired treatment is taken when the state deteriorates. Need to be taken.

Therefore, conventionally, for example, a connection device and a wireless telephone are each provided with a circuit for detecting a decrease in the received electric field strength, and an alarm is issued or a transmission / reception operation is forcibly stopped (hereinafter referred to as a hard cut) according to the detection result of this circuit. I am trying to process.

FIG. 1 shows an example of the configuration of a wireless telephone device having the above functions. In the figure, the connection device 1 conducts the switch circuits 11 and 12 by the control circuit 10 during a call, supplies the power output from the rectifier circuit 13 to the transmitter 14 and the receiver 15, respectively, and operates them. The downlink call signal coming through the wired telephone line 2 is guided to the transmitter 14 via the hybrid circuit 16 and the amplifier circuit 17, modulated there, and sent out to the wireless telephone 3 from the antenna 18 and wirelessly transmitted from the wireless telephone 3. The receiver 1 receives the downlink call signal coming through the line via the antenna 19.
5, the demodulated call signal is received and demodulated by the amplifier circuit 20.
Also, the data is sent to the wired telephone line 2 via the hybrid circuit 16.

On the other hand, the wireless telephone 3 uses the battery 30 as a power source, and the battery 3
The output of 0 is supplied to the transmitter 34 and the receiver 35 through the switch circuits 32 and 33 which are conducted by the command of the control circuit 31 to be operated, and in this state, the downlink coming from the connection device 1 via the wireless line. The call signal is received and demodulated by the receiver 35 via the antenna 36, and the demodulated call signal is amplified to a predetermined level by the amplifier circuit 37 and then supplied to the handset 38 to be generated as voice and input by the transmitter 39. The amplified upstream call signal is amplified to a predetermined level by the amplifier circuit 40 and then used as a modulation input signal of the transmitter 34, whereby the modulated radio signal output from the transmitter 34 is transmitted to the antenna 4
1 to the connection device 1.

The connection device 1 and the wireless telephone 3 are provided with a reception electric field detection circuit 2 provided as a reception radio field intensity detection means.
When a decrease in the received electric field strength is detected by the control circuits 1 and 42, an operation stop signal is supplied from the control circuits 10 and 31 to the transceiver to disconnect the wireless line, thereby returning to the standby state. .

[Problems of background technology]

However, such a conventional radiotelephone device has a reception electric field detection circuit 21, which is provided in the connection device 1 and the radiotelephone 3.
Since the drop determination levels of 42 are set to be equal to each other, when the received electric field strength is different due to the difference in propagation loss due to the frequency difference between the up and down wireless lines, whichever of the connection device 1 and the wireless telephone 3 is used. On the other hand, it was not known whether or not the received electric field was detected to be lower first, which caused various troubles in the call.

For example, when the connection device 1 first detects the deterioration of the received electric field strength and makes a strong cut, the receiving system of the wireless telephone 3 suddenly cuts off the receiving carrier, and at that moment, a sudden noise of “snap” is generated in the handset. From then on, as long as the receiving system is operating, a large noise of "Za" will continue to be output from the handset. On the other hand, when the wireless telephone 3 first detects the deterioration of the received electric field strength and makes a strong cut, the same large noise is generated in the receiving system of the connection device 1, which is generated by the other party of the call via the wired telephone line. It will be sent to the telephone. In this way, no matter which of the connection device 1 and the wireless telephone 3 makes a strong switch first, noise is generated in the receiving system of the other party, which causes the speaker of the wireless telephone 3 and the other party of the wired telephone line side. It is not preferable because it makes the speaker uncomfortable.

However, among them, the noise sent from the connection device 1 to the wired telephone line is generally attenuated by the influence of the transmission loss and the transmission characteristic before reaching the other party via the wired telephone line or the exchange. Therefore, the discomfort felt by the other speaker is somewhat reduced. On the other hand, since the noise generated in the receiving system of the wireless telephone 3 is output as loud as it is from the handset,
The discomfort experienced by the speaker is greater than that of the other speaker on the wired telephone line side and cannot be ignored. Therefore, it is important to take measures against at least the noise output from the wireless telephone 3.

Further, generally, in this type of device, when the received electric field strength of the wireless telephone is lowered, it is determined that the wireless telephone has gone out of the communication area and the wireless telephone issues an alarm. However, if a decrease in the received electric field strength is first detected on the connection device 1 side, the wireless telephone 3 suddenly disconnects the line with the connection device 1 without any alarm being issued.
Very unfavorable.

Therefore, conventionally, for example, measures as shown in JP-A-54-75201 are taken. That is, when a decrease in the received electric field strength is detected on the connection device side, the connection device transmits an alarm signal to the wireless telephone to cause the wireless telephone to generate an alarm sound. Then, when the decrease in the received electric field strength lasts for a certain period of time, a strong cutoff signal is transmitted from the connection device to the wireless telephone to shift the wireless telephone to a standby state, and after a certain delay time, the connection device itself It is designed to shift to a standby state. With this configuration, the connection device and the wireless telephone can be put into the standby state almost at the same time, which prevents a problem that annoying noise is output at the time of a strong cut. Further, since an alarm is issued in the wireless telephone before the line is disconnected, the problem of sudden disconnection can be prevented.

However, in such a device, since a warning signal and a strong cutoff signal are always transmitted from the connection device to the wireless telephone at the time of making a strong cutoff, these warning signal and strong cutoff signal are output as noise in the wireless telephone. Sometimes. further,
If the condition of the wireless line from the connection device to the wireless telephone is deteriorated, the alarm signal and the deadline signal will not be correctly transmitted to the wireless telephone, which will not generate an alarm or restore the wireless telephone to the standby state. It was sometimes gone.

[Object of the Invention]

The present invention has been made by paying attention to the above circumstances, and when almost the same degree of deterioration of the transmission / reception state occurs in the up and down of the wireless line, the wireless telephone side always detects this and issues an alarm. It is possible to prevent the noise from occurring at least in the wireless telephone to improve the call quality and to eliminate the need for complicated controls and circuits to prevent the noise. It can be realized with a simple circuit configuration, and even if the transmission / reception state is significantly deteriorated due to only the uplink of the wireless line, it can be detected without fail and it is possible to take appropriate measures such as aggressiveness. It is an object of the present invention to provide a wireless telephone device that operates.

[Outline of Invention]

In order to achieve the above object, the present invention provides each of the radio wave intensity detecting means of the wireless telephone and the connection device with a determination level consisting of a finite value, so that the transmission / reception occurring in either the up or down direction of the wireless line. The deterioration level of the state is also detected, and the judgment level of the reception field strength detection means in the connection device is set to be relatively lower than the judgment level of the reception field strength detection means in the wireless telephone, and the reception radio wave in the wireless telephone is set. When the decrease in strength is detected continuously for a certain period of time or when it becomes more than a certain period of time, the wireless telephone stops the transmission / reception operation, and the connection device detects the stop of the transmission operation of this wireless telephone to establish a connection. The device is designed to stop its own transmission / reception operation.

As a result, according to the present invention, when the wireless line becomes defective to the same extent in both the up line and the down line as in the case where the wireless telephone moves out of the communication range of the connection device, that is, when the normal line deterioration occurs, When the wireless telephone detects a decrease in the received radio wave intensity and the decrease is continuously detected for a certain time or more or exceeds a certain time rate, the transmission / reception operation of the wireless telephone is stopped. By detecting the stop of the transmission operation of the wireless telephone, the connection device stops the transmission / reception operation after the wireless telephone. Therefore, when returning to the standby state due to normal line deterioration, the wireless telephone must always make a strong cut first, so that no annoying noise is generated from the wireless telephone.
Further, in the case of a strong cut, no control signals such as a strong cut signal and a warning signal are exchanged between the wireless telephone and the connection device. Therefore, there is no fear that the wireless telephone will output noise due to the above-mentioned control signal in the case of a strong switch. In addition, the control signal is not correctly transmitted due to the deterioration of the state of the wireless line, so that the problem that the deadline operation and the alarm generation operation are not performed does not occur at all.

Further, according to the present invention, the generation of noise in the wireless telephone is set so that the determination level of the wireless telephone is set to be relatively higher than the determination level of the connection device as described above, so that the wireless telephone always performs the deadline first. To prevent this. Therefore, for example, it is possible to appropriately control the deadline timing between the wireless telephone and the connection device, and prevent the generation of noise without providing a noise blocking circuit such as a switch or a filter, so that the standby state is restored. There is an advantage that the control procedure and the circuit configuration of the wireless telephone are not complicated.

Also, even though it is lower than the judgment level of the wireless telephone, the connection device is also provided with a finite judgment level, so even if the transmission / reception state is significantly deteriorated only by the uplink of the wireless line, it is overlooked. It is possible to detect it without any trouble, and thus it is possible to perform a process such as a deadline first from the connection device side. As a result, even if, for example, only the uplink from the wireless telephone to the connection device becomes defective, it is possible to prevent the problem that the call is continued in the state where the quality is deteriorated in only one direction.

Since the wireless telephone first makes a strong cut, noise is unavoidable in the receiving system of the connection device. However, the noise sent from the connection device to the wired telephone line is generally attenuated due to the influence of the transmission loss and the transmission characteristic before reaching the other party's side via the wired telephone line or the exchange. Therefore, the discomfort experienced by the other speaker is relatively small.

However, in order to further reduce the discomfort felt by the other speaker, the present invention is configured as follows. That is, in the connection device, the reception circuit that receives the radio wave transmitted from the wireless telephone and the wired telephone line are connected within a period from the time when the decrease in the strength of the radio wave received from the wireless telephone is detected until the transmission / reception operation is stopped. The audio signal path between them is cut off.

With this configuration, the period during which noise is transmitted from the connection device to the wired telephone line is limited to the period from the time when the decrease in the received signal strength from the wireless telephone is detected until the voice signal path is disconnected. It will be. For example, if the voice signal path is immediately cut off immediately after the decrease in the strength of the radio wave received from the wireless telephone is detected, the period during which noise is transmitted to the wired telephone line becomes very short, and as a result, the other party's speaker The influence of the noise on is almost negligible.

Example of Invention

FIG. 2 is a circuit block diagram of a wireless telephone device according to an embodiment of the present invention. In the figure, the same parts as those in FIG. 1 are designated by the same reference numerals and detailed description thereof will be omitted.

The connection device 1a and the wireless telephone 3a are respectively provided with reception electric field detection circuits 21a and 4a as reception electric field intensity detection means.
2a is provided. These reception electric field detection circuits 21a,
Reference numeral 42a is, for example, for judging the reception carrier level, and its lowering judgment level is set to be relatively lower on the connection device 1a side than on the wireless telephone 3a side. This value is 0 dBμV and 20 dBμ, respectively, so that the difference between the input levels of the receivers 15 and 35 is 10 dB or more, respectively.
It is set to about V. That is, the wireless telephone device according to the present embodiment reduces a normal received electric field strength that occurs when the wireless telephone 3a moves out of the communication area of the connection device 1a.
The wireless telephone 3a always detects first.

By the way, the decrease in the received electric field strength is caused by the wireless telephone 3
It is extremely convenient for the wireless telephone device connected to the wired telephone line 2 to detect the a side first in the following points.
That is, the level of the upstream call signal sent to the wired telephone line 2 is set to a level that is somewhat higher than that of the wired telephone, but the level of the downstream call signal that arrives at the connection device 1a via the wired telephone line 2 is the level of the wired telephone. It tends to change in the range of 6 dB to 32 dB due to the propagation loss in the line 2, and generally tends to be low. Therefore, when the level of the call signal is low (32 dB propagation loss), the level of the call signal transmitted to the wireless telephone 3a (listening level) decreases, and the S / N of the signal is sent to the connection device 1a. It tends to be much worse than the S / N of the transmitted signal. Therefore, the wireless telephone 3a
It is very advantageous in terms of design and the like that the side first detects the decrease in the received electric field strength, which matches the property of the wireless telephone device.

Further, switch circuits 22 and 23 are provided between the amplifier circuit 17 and the transmitter 22 of the connection device 1a and between the amplifier circuit 20 and the hybrid circuit 16, respectively. These switch circuits 22 and 23 are the reception electric field detection circuit 2
When it is detected by 1a that the received electric field intensity is below the judgment level, the control circuit 10a opens the control signal to disconnect the voice circuit for the wired telephone line 2.

With such a configuration, for example, when the wireless telephone 3a goes out of the talking area and the received electric field strength decreases, the received electric field strength decrease is first detected by the received electric field detection circuit 42a of the wireless telephone 3a. It Then, the control circuit 31a of the radio telephone 3a first monitors the continuous time from the time when the received electric field is detected to decrease as shown in FIG. 3, for example, and the electric field decrease state is a constant time t1 (for example, 1 to 3 seconds). When the above is continuous, a drive signal is output to the alarm generation circuit 43 to generate an alarm indicating that the communication area is outside. Here, the reason that the alarm is generated after the electric field is continuously decreased for a certain period of time is to prevent erroneous detection of a temporary decrease of the electric field due to fading, for example.

When the alarm is issued, the control circuit 31a further monitors the continuation of the electric field decrease as shown in FIG. In this state, the subscriber notices the alarm and returns the wireless telephone 3a to the inside of the talking area, and when the received electric field strength of the wireless telephone 3a returns to the level exceeding the judgment level, the control circuit 31a
Stops the generation of the alarm and returns to the operation of repeating the monitoring operation of the received electric field drop and the monitoring operation of the call end.

On the other hand, when the subscriber does not return the wireless telephone 3a to the communication area in response to the generation of the alarm or the electric field is lowered due to a failure or the like, the control circuit 31a causes the reception electric field to decrease as shown in FIG. When the electric field drop state continues for t2 (for example, 10 to 30 seconds or more) continuously by monitoring the state,
A control signal is output to stop the operation of the transmitter 34 and the receiver 35, and the wireless line is shut off. After this deadline, the wireless telephone 3a returns to the standby state.

On the other hand, the connection device 1a has not yet detected a decrease in the received electric field while the alarm is being issued by the wireless telephone 3a, and as a result, continues the call operation. However, when the radio telephone 3a makes a strong switch, the reception electric field disappears and the reception electric field detection circuit 21a generates a drop detection signal. Then, the control circuit 10a first disconnects the voice circuit by opening the switch circuits 22 and 23 as shown in FIG. 4, for example, and then the detection signal of the received electric field decrease is kept for a certain time t3 (for example, 1 to 3 seconds). At consecutive points, the user makes a deadline and returns to the standby state.

It is assumed that the state of the uplink from the wireless telephone 3a to the connection device 1a becomes defective due to changes in radio wave propagation conditions, etc., and as a result, only the received electric field strength at the connection device 1a is greatly reduced. Then, the decrease in the received electric field strength is detected by the received electric field detection circuit 21a of the connection device 1a, and as a result, the control circuit 10a of the connection device 1a.
Outputs an operation stop signal to the transceiver to disconnect the wireless line as in the conventional operation, thereby stopping the transmission of radio waves and returning to the standby state. On the other hand, the wireless telephone 3a also detects the interruption of the radio wave from the connection device 1a, stops the transmission of the radio wave of its own device, and returns to the standby state.

In this way, according to the present embodiment, the lowering judgment level of the reception electric field detecting circuit 21a provided in the connection device 1a is set lower than the lowering judgment level of the reception electric field detecting circuit 42a provided in the wireless telephone 3a. When the state of the uplink and the downlink of the wireless line deteriorates in substantially the same manner, that is, when the state of the normal line deteriorates, the decrease in the received electric field strength is always detected first by the wireless telephone 3a, As a result, the processing for issuing an alarm and making a deadline is performed by the wireless telephone 3a.
Will be conducted under the initiative of. Therefore, there is no problem that the noise accompanying it is generated in the radiotelephone 3a at the time of a strong cut. In addition, the connection device 1a to the wireless telephone 1a
To the wireless telephone 1a without sending a control signal for alarm generation to
Thus, an alarm can be reliably generated, and the device can be returned to the standby state without sending a control signal such as a strong cutoff signal. Therefore, the connection device 1a and the wireless telephone 3
The control procedure of a can be simplified, and the problem that a large noise due to the control signal is generated from the wireless telephone 3a does not occur.

Further, in the present embodiment, the connection device 1a is provided with the switch circuits 22 and 23 for disconnecting the voice circuit, and when the disconnection of the radio wave received from the wireless telephone is detected, the switch circuits 22 and 23 are provided.
I am trying to open 23. Therefore, even if noise occurs in the receiving circuit of the connection device 1a after the wireless telephone 3a makes a strong cut, it is prevented that this noise continues to be sent to the wired telephone line 2, and as a result, the discomfort felt by the other speaker is received. Can be reduced.

It should be noted that in the circuit configuration of FIG.
3, the switch circuit 22 of the transmission system is opened at the same time. This is because the actual circuit configuration shares the switching control signal output from the control circuit 1a.
Originally, it is not necessary to open the switch circuit 22 of the transmission system. By the way, the switch circuit 22 of the transmission system transmits various signals on the wired telephone line 2 to the wireless telephone 3a during line connection control.
It functions as a mute circuit to prevent the signal from being sent to.

Further, since the reception electric field decrease determination level of the connection device 1a is set to a finite value instead of zero, the wireless telephone 3a is temporarily assumed.
Even if only the state of the uplink from the connection device 1a to the connection device 1a is significantly deteriorated, the connection device 1a can detect this deterioration and return the device to the standby state. Therefore, it is possible to prevent a problem in which a call is made as it is in a state where the transmitted voice of the speaker of the wireless telephone 3a cannot be heard well by the other speaker.

The present invention is not limited to the above embodiment. For example, a wireless telephone device to which the multi-channel access method is applied normally searches for a free communication channel at a low electric field level, and therefore has a low decision level electric field detection circuit. Therefore, as another embodiment, the electric field detection circuit for searching for an empty channel may be used as the reception electric field detection circuit of the present invention during a call. By doing so, it is not necessary to newly provide an electric field detection circuit, and the circuit configuration can be simplified accordingly. Further, in the above-described embodiment, the electric field detection circuit that detects the carrier level is used, but another circuit that detects the tone level or the noise level may be applied. Further, as for the electric field decrease state, instead of monitoring the continuous time, it may be possible to detect whether or not the electric field strength has decreased within a predetermined time period more than a predetermined time period, that is, a time rate. Further, as a means for stopping the operation of the transceiver, the power supply to the transceiver may be turned off. In addition, the value of the electric field detection level, the means for issuing an alarm, and the like can be modified in various ways without departing from the scope of the present invention.

〔The invention's effect〕

As described above in detail, according to the present invention, each of the received radio wave intensity detection means of the wireless telephone and the connection device is provided with a determination level consisting of a finite value, so that transmission / reception that occurs on either the up or down side of the wireless line. The deterioration of the state is also detected, and the determination level of the reception radio field intensity detection means in the connection device is set relatively lower than the determination level of the reception radio field intensity detection means in the wireless telephone,
The wireless telephone stops the transmission operation when the decrease in the received radio wave intensity is continuously detected for a certain time or more or becomes a certain time rate or more by the above-mentioned wireless telephone, and the transmission operation of the wireless telephone is stopped. Is detected by the connection device, and the connection device stops its own transmission / reception operation.

Therefore, according to the present invention, when approximately the same degree of deterioration of the transmission / reception state occurs in the up and down of the wireless line, the wireless telephone side can detect this first and issue an alarm and make a deadline. As a result, at least noise can be prevented from occurring in the wireless telephone to improve the call quality, and this can be realized with a simple circuit configuration without the need for complicated control and circuits, and the wireless line It is possible to provide a radiotelephone device capable of surely detecting even if a great deterioration of the transmission / reception state occurs only by going up and performing an appropriate treatment such as a deadline.

[Brief description of drawings]

FIG. 1 is a circuit block diagram of a conventional wireless telephone device,
FIG. 2 is a circuit block diagram of a radiotelephone device in one embodiment of the present invention, and FIGS. 3 and 4 are flowcharts used for explaining the operation of the device. 1a ... Connection device, 2 ... Wired telephone line, 3a ... Wireless telephone, 21a, 42a ... Received electric field detection circuit, 22, 23 ...
Switch circuit for disconnecting voice circuit, 43 ... Alarm generating circuit.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Ryoji Kawasaki 1-6, Saiwaicho, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Public Corporation (72) Inventor Kazuhiro Yoshizawa 1-6-6, Sachimachi, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Public Corporation (72) Inventor Masao Ikoma 5-33-1 Shiba, Minato-ku, Tokyo Inside NEC Corporation (72) Inventor Akio Yotsuya 5-33-1 Shiba, Minato-ku, Tokyo NEC Incorporated company (72) Inventor Koichi Ito 1-3-1, Asahigaoka, Hino-shi, Tokyo Inside Hino Factory, Higashi Koshibaura Electric Co., Ltd. (72) Inventor Shoji Fuse 3-1-1, Asahigaoka, Hino-shi, Tokyo (56) Reference JP 54-75201 (JP, A) JP 55-60350 (JP, A) JP 57-152826 (JP, U)

Claims (4)

[Claims] 1. A radiotelephone device comprising a connection device connected to a wired telephone line and a radiotelephone connected to the connection device via a radio line, wherein the radiotelephone is a radio wave received from the connection device. A first received radio wave intensity detection means for detecting that the intensity has dropped below a first determination level consisting of a finite value, and a drop in the received radio wave intensity is detected by the first received radio wave intensity detection means. Accordingly, an alarm generating means for generating an alarm to that effect, and for stopping the transmission / reception operation of the wireless telephone when the decrease of the received radio wave intensity continues for a certain time or more or becomes a certain time rate or more The connection device has a second determination level that is lower than the first determination level and is a finite value, and the received signal strength from the wireless telephone is the second determination level. A second received radio wave intensity detection means for detecting a decrease in the level or less, and a transmission / reception operation of the connection device itself in response to the decrease in the received radio wave intensity detected by the second received radio wave intensity detection means. At least, and the wireless telephone first detects a decrease in received radio wave intensity by setting the first determination level of the wireless telephone relatively higher than the second determination level of the connection device. A radiotelephone device characterized by being configured so as to stop the transmission / reception operation. 2. The means for stopping the transmission / reception operation of the connection device detects a decrease in the received radio wave intensity by the second received radio wave intensity detecting means, and this state continues for a certain time or more or becomes a certain time rate or more. The radiotelephone device according to claim (1), which suspends the transmission / reception operation of the connection device in the event of a failure. 3. The second received signal strength detection means is an idle channel detection means for determining that the wireless line is idle during standby or connection control for incoming and outgoing calls. The wireless telephone device according to claim (1). 4. The period from the time when the second reception radio field intensity detecting means detects that the radio field intensity received from the wireless telephone has dropped below a second judgment level until the connection device stops the transmission / reception operation. Claims (1) to (3), wherein the means for disconnecting the audio signal path between the receiving circuit for receiving the radio wave transmitted from the wireless telephone and the wired telephone line is included therein. The wireless telephone device according to any one of paragraphs.