JP3332548B2 - Digital cordless telephone equipment - Google Patents

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 apparatus called a second-generation cordless telephone capable of communicating with a plurality of telephones by radio communication separately from a general public telephone line. It is about improvement.

[0002]

2. Description of the Related Art In recent years, information communication plays an extremely important role, and in particular, expectations regarding mobile communication systems are rapidly increasing. Under such circumstances, for the advanced information society of the 21st century, it is a small terminal that can be carried by individuals, and can be used at home, office, and even outdoors with the same terminal. A simple mobile phone system that has enhanced the confidential communication function by digitizing communication is about to be realized.

[0003] The simplified portable telephone system is also called a personal handy phone (PHP) or a digital cordless telephone. This is not merely a digitization of an existing cordless telephone but by standardizing an interface in a wireless section. It can be used not only indoors such as homes and offices but also outdoors.

[0004] The main features are that a 1.9 GHz band is allocated to the used frequency band, the access method is 4-wave multiplexing TDMA (time division multiplex access), and the transmission method is TDD (time division bidirectional access). Transmission), and the antenna power of the mobile station is 10 mW or less. Also, as an auxiliary communication function, direct communication between slave units is possible as in a transceiver. The audio is compressed and transmitted by the 32 kbit / sec ADPCM method.

FIG. 4 is a block diagram showing a general circuit configuration of a slave unit which is a mobile station of a digital cordless telephone. Hereinafter, the configuration of the cordless telephone will be described together with its operation. First, on the receiving side, only an RF signal received by an RF filter and an RF amplifier (AMP) 11 is extracted from a high frequency signal (hereinafter, referred to as an RF signal) input from an antenna and amplified. Has become. The tuning VCORX (voltage controlled oscillator on the receiving side) 17 is a TCXO.
(Temperature Compensated Crystal Oscillator, that is, a crystal oscillator with temperature compensation), and a PLL (Phase Locked Loop) frequency synthesizer (variable frequency divider) driven by a control signal from the CPU 23 It receives 19 signals and produces a reference clock signal. Then, the reference clock signal and the RF filter and the RF output from the RFAMP 11 are output.
After mixing with the signal in the first (1ST) MIX circuit 12, only the difference of the frequency spectrum generated using the non-linear portion of the transistor is taken out through the IF filter and the IF amplifier AMP13. The signal thus extracted is the first intermediate frequency signal.

Next, a fixed clock signal is generated in the VCOIF 18 using the TCXO or another oscillating circuit, and the clock signal and the first intermediate frequency signal are converted into a second (2ND) MIX circuit. The mixing is performed again at 14, and the second intermediate frequency signal is extracted through the IF filter and IFAMP 15. The second intermediate frequency signal is demodulated by the demodulation circuit 16 into a π / 4-shifted 4-phase QPSK
Demodulation (that is, a quadrature phase shift, that is, a type of linear modulation scheme used in a digital wireless relay scheme).
At this time, the IF filter and IFAMP 15 and the demodulation circuit 16 simultaneously detect the input reception level.

Subsequently, the TDMA processing circuit 21
DMA processing (time-division separation processing) is performed.
D / A conversion of M / PCM (PCM is pulse code modulation, ADPCM is adaptive difference PCM) is performed. After that, amplification and BPF control are performed by the audio processing circuit 25.
Subsequently, in the line control circuit 27 (however, in the case of a master unit, it becomes a line control circuit and a speech network circuit),
Amplification processing and impedance conversion processing are performed to obtain a signal that can be supplied to a speaker, an earphone, or the like, and speaker output, ringer output, connection to a telephone line, and the like are performed.

A data signal such as a message is also demodulated by a demodulation circuit 16 and then passed through a TDMA processing circuit 21 to be decoded by a data demodulation circuit 22 composed of a gate array and a DSP (digital signal processor). Processing such as error correction and error correction is performed by a control signal from the CPU 23. Thereafter, the processed data is stored in a memory (RAM) in the CPU 23, and the CPU 23 performs a process based on the stored data (such as a message).

On the transmitting side, on the other hand, in the case of the master unit, the audio signal from the microphone is emitted from the telephone line and the user, and in the case of the slave unit, the audio signal from the microphone is emitted from the user. The signal is converted into an electric signal by the line control circuit 27 and digitized by the A / D conversion circuit 30 of ADPCM / PCM. For data such as messages, code conversion and error correction are performed by the data modulation circuit 28 using various tables in a memory (RAM) under the control of the CPU 23. Then, the digitized data of voice and data is further subjected to TDMA processing by a TDMA processing circuit 29, and then modulated by a π / 4 shift four-phase QPSK by a modulation and MIX circuit 31. After mixing with the clock signal from the VCOTX 20 (which is a voltage-controlled oscillator on the transmission side) corresponding to the selected channel, only the necessary frequency components are extracted by the RF filter and the RFAMP 32 and amplified.
Thereafter, only the output is efficiently transmitted through the antenna.

In the figure, a display processing circuit (display key)
In 33, control of display elements such as LEDs and LCDs and control of input keys are performed. In the DTMF generation circuit 26, DTMF is controlled by an instruction from the CPU 23.
A signal or a melody is generated.

[0011]

By the way, in the above-mentioned digital cordless telephone, it is possible to communicate with a partner station indoors via a base unit and outdoors by a public base station. The antenna power of the mobile unit is set to 10 mW or less, the antenna power of the public base station is set to 500 mW or less, and the antenna power of the slave unit (mobile station) is set to 10 m or less.

[0012] Therefore, especially for outdoor use, it is necessary for the slave unit to be located in the communication zone of one public base station, and the power level of the slave unit is constant. Therefore, the reception level is naturally affected by the communication distance with the public base station, and is considerably affected by the deterioration of the radio wave condition due to buildings and the like. Furthermore, when the slave unit has left the communication zone of one public base station or when asynchronous interference has occurred while waiting,
Unless processing for switching the communication zone by switching channels is performed, communication becomes difficult.

Thus, in the slave unit, immediately after the power is turned on,
Alternatively, at the time of standby, communication with the public base station or the master unit may be difficult due to the various causes described above. If such a state is temporary, there is no problem, but if it continues, there is a disadvantage that power is wasted. As a result, the life of the mounted battery may be shortened, and the transmission / reception performance may be reduced at an early stage.

The present invention has been made in view of the above situation, and has as its object to provide a digital cordless telephone device having a function of saving a battery to be mounted.

[0015]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a slave unit capable of communicating with a destination communication station via a base station or a destination public base station by wireless communication. A digital cordless telephone device comprising: a determination unit that determines whether or not the slave unit has received broadcast channel information transmitted from the master unit or the public base station when power is turned on or a call is disconnected. Power cutoff means for cutting off supply of power to the apparatus, and power cutoff control for turning off the power by driving the power cutoff means when the determination means determines that the broadcast channel information has not been received. Means, and the power-off control means.
Further includes first and second timers for measuring a predetermined time.
And a warning sound generator, wherein the determination means
If it is determined that the channel information has not been received,
Start a first timer and a second timer;
At the same time as the end of the timer
To generate an audible alarm and then end the timing of the second timer.
At the same time, the power-off means is driven to turn off the power.
It is characterized by that.

Further, in the invention according to a second aspect of the present invention, the power-off control means further includes first and second timers for counting a predetermined time, and an alarm sound generator, and the determination means includes: When it is determined that the broadcast channel information has not been received, the first timer and the second timer are started, and at the same time as the time counting of the first timer ends, the warning sound generator is driven to issue a warning. A sound is generated, and then the power is turned off by driving the power-off means simultaneously with the end of the time counting of the second timer.

[0017]

According to the above arrangement, in the slave unit of the digital cordless telephone apparatus according to the present invention, when the power is turned on or the call is disconnected, the notification transmitted from the master unit or the public base station by the judging means. It is determined whether channel information has been received. If it is determined that the broadcast channel information has not been received, the power-off control unit drives the power-off unit and cuts off the power supply to the apparatus.

In this case, the power-off control means is configured to include first and second timers for measuring a predetermined time and a warning sound generator for warning that communication is difficult. In such a case, the power-off control is performed as follows. That is, if it is determined that the broadcast channel information has not been received, the first and second
Start the timing operation of each of the timers. And
At the same time as the end of the time counting operation of the first timer, the warning sound generator is driven to generate a warning sound. Thereafter, at the same time as the end of the timing operation of the second timer, the power-off means is driven to turn off the power.

As a result of the above, when communication is difficult, such as when the power is turned on to carry the communication and the communication is interrupted, etc. Since this is warned to the user and the power supply to the device is cut off, wasteful power consumption is avoided.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be specifically described below with reference to the drawings. FIG. 1 is a schematic diagram showing an example of a communication zone in which a digital cordless telephone device according to the present invention is used. As shown in the drawing, an indoor master unit P is installed indoors, and a mobile slave unit PS that can be taken out and moved outdoors has a communication area X surrounded by a broken line in the figure.
Communication with the indoor parent device P is enabled. In addition, an outdoor base station CS is installed outdoors, and the mobile terminal PS can communicate with the outdoor base station CS in a communicable area Y surrounded by a dashed line in the figure. Further, in this example,
The indoor parent device P exists in the communicable area Y of the outdoor base station CS, and the mobile child device PS can communicate with both the indoor parent device P and the outdoor base station CS.

FIG. 2 is a block diagram showing a main configuration of a slave unit of the digital cordless telephone device according to the present invention. This device includes an antenna 1, an RF / IF unit 2, a modem unit 3, a digital signal processing unit 4, an audio signal processing unit 5, a microphone, a ringer, and a speaker connected to the audio signal processing unit 5. Control unit 6 for controlling each circuit block
And two timers A and B provided in the control unit 6;
It comprises a warning sound generator 7, a power switch 8 and a power supply 9.

Next, the circuit operation of the above configuration will be described. In the RF / IF unit 2, an RF filter and an RF signal are selected from high-frequency signals (RF signals) input from the antenna 1.
Only the input received RF signal is amplified by the amplifier and further frequency-converted. The modulation / demodulation unit 3 performs modulation / demodulation of π / 4 shift 4-phase QPSK. Digital signal processing unit 4
In, digital signal processing such as TDMA processing is performed. Then, in the audio signal processing unit 5, ADPCM / PC
Conversion of M and D / A conversion and A / D conversion are performed.
The microphone connected to the audio signal processing unit 5 is used to input a transmission sound, the ringer is used to output a ringing sound, and the speaker is used to output a reception sound. Further, the power supply unit 9 supplies power to each unit via the power switch 8.

On the other hand, various kinds of control data extracted by the digital signal processing unit 4 at the time of reception are input to the control unit 6. At the time of transmission, it outputs control data to the digital signal processing unit 4. Further, the control unit 6 includes an RF / IF unit 2
Field intensity data of a received radio wave from the Internet. When communication with the public base station or the master unit is difficult, the control unit 6 drives the warning sound generation unit 7 with a predetermined time-out of the timer A to generate a warning sound. After that, the power switch 8 is driven when the timer B has timed out for a predetermined time, so that the power is not supplied from the power supply unit 9 to each unit.

FIG. 3 is a flowchart showing a process in a case where communication with the public base station or the master unit becomes difficult during standby. Specifically, one of the control units 6 in FIG. This is a flowchart showing the control operation. In general, a cordless telephone device enters a so-called standby state immediately after power-on or when a communication channel is released due to a call disconnection (including an abnormal disconnection due to a failure in channel switching or the like). In this state, the slave unit starts scanning the BCCH (slot having information on superframes, that is, broadcast channel information) transmitted from the public base station or the master unit.

Therefore, in the digital cordless telephone according to the present invention, it is determined whether or not the broadcast channel is synchronized by tuning to the frequency having the maximum input level based on the electric field strength data (S1). If synchronization is not achieved (No in S1), the timers A and B set to a predetermined time are started (S2). Here, the set time of the timer B is longer than the set time of the timer A. Subsequently, it is checked whether or not the timer B has timed out (S3). If the time has timed out (Yes in S3), the power switch 8 is driven to cut off the power supply from the power supply unit 9 to each unit ( S4).

If the timer B has not timed out (No in S3), it is further confirmed whether or not the timer A has timed out (S5), and if it has timed out (Yes in S5), Drives the alarm sound generator 7 to output an alarm sound (S6). If the timeout has not occurred (No in S6), the process returns to step S1.

On the other hand, when the broadcast channel is synchronized (S
In the case of (Yes in 11), it is confirmed whether or not the warning sound is currently being sent (S7). When the warning sound is transmitted (in the case of Yes in S7),
The generation of the alarm sound is stopped by the alarm sound generation unit 7 (S
8) After that, if the warning sound is not transmitted (No in S7), the timer A and the timer B are immediately set to their initial values (S9), and the PCH (necessary for incoming call) is set. (S10), a processing routine in a standby state (S10). Thereafter, if the mobile terminal goes out of the communication range or the synchronization is lost while executing the processing routine in the standby state, the process returns to step S1 again.

[0028]

According to the present invention described above, when the slave unit is in a state where it is difficult to communicate with the master unit or the public base station immediately after the power is turned on or when the call is disconnected, the state is maintained to some extent. Automatically powers down, thus effectively saving battery power consumption. In addition, before the power is turned off, a warning sound is issued to warn that communication is difficult, so that forgetting to turn off the power can be prevented, and the digital cordless telephone system can be economically operated.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an example of a communication zone in which a digital cordless telephone device according to the present invention is used.

FIG. 2 is a block diagram showing a main configuration of a slave unit of the digital cordless telephone device according to the present invention.

FIG. 3 is a flowchart illustrating a process when communication with a public base station or a base unit becomes difficult during standby;

FIG. 4 is a block diagram showing a general circuit configuration of a slave unit which is a mobile station of a digital cordless telephone.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Antenna 2 RF / IF part 3 Modulation / demodulation part 4 Digital signal processing part 5 Audio signal processing part 6 Control part 7 Warning sound generation part 8 Power switch 9 Power supply part A Timer B Timer P Base unit PS Slave unit CS Public base station X Parent Communication zone Y Communication zone of public base station

Claims (1)

(57) [Claims] 1. A digital cordless telephone device having a handset capable of communicating with a destination communication station via a base station or a destination public base station by wireless communication, wherein the handset includes a power supply. A determination unit for determining whether or not broadcast channel information transmitted from the master unit or the public base station is received at the time of insertion or disconnection of a call; a power supply disconnection unit for cutting off power supply to the device; determining means, when it is determined that it has not received the broadcast channel information, together with and a power-off control means for cutting the power supply by driving the power supply cutting means, the power-off control means further predetermined Time
The system includes first and second timers and a warning sound generator, and the determination unit does not receive the broadcast channel information.
If the first timer and the second timer
Start the timer, and at the same time
Driving the warning sound generator to generate a warning sound,
Then, at the same time when the timing of the second timer ends, the power-off
A digital cordless telephone device wherein a step is driven to turn off a power supply .