JPH07231291A - Digital cordless telephone set - Google Patents

Abstract

PURPOSE:To effectively save depleted power of a battery by interrupting power supply automatically when communication between a slave set and a master set or a public base station has a difficulty and the state lasts for some time. CONSTITUTION:Whether or not notice channel synchronization is taken is decided in the digital cordless telephone set by tuning in to a frequency whose input level is maximum based on electric field strength data. When the synchronization is not taken, timers A, B, whose expiration is set to a prescribed time are operated. The expiration time of the timer B is set longer than that of the timer A. Whether or not the timer B is up is confirmed succeedingly and when the timer B is up, a power switch 8 is driven and supply of power from a power supply section 9 to each section is interrupted. When the timer B is up whether or not the timer A is up is confirmed and when the timer A is up, a warning tone 7 is raised to be sent.

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 called a second generation cordless telephone which is capable of communicating with a plurality of telephones by wireless communication in addition to 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 expectations for mobile communication systems are rapidly increasing. Under such circumstances, toward the advanced information society of the 21st century, it is a small terminal that can be carried by an individual, and can be used at home, office, and even outdoors by the same terminal. , A simple mobile phone system with enhanced confidential functions by digitizing communication is about to be realized.

The simple mobile phone system is also called a personal handy phone (PHP) or a digital cordless phone, but this is not merely a digitization of the current cordless phone, but is made possible by standardizing the interface in the wireless section. , Not only for indoor use such as at home or office, but also for outdoor use.

The main features are that the frequency band used is 1.9 GHz, the access method is 4-wave multiplexing TDMA (time division multiple access), and the transmission method is TDD (time division bidirectional). Transmission), and the antenna power of the mobile station is 10 mW or less. In addition, as an auxiliary communication function, it is also possible to directly talk between handset units like a transceiver. The voice is compressed and transmitted by the ADPCM system of 32 kbit / sec.

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. The configuration of this cordless telephone will be described below along with its operation. First, on the receiving side, only the RF signal received by the RF filter and RF amplifier (AMP) 11 is extracted and amplified from the high frequency signal (hereinafter referred to as RF signal) input from the antenna. Has become. Further, the VCORX (voltage control oscillator on the receiving side) 17 for tuning is a TCXO.
(Temperature Compensated Crystal Oscillator, that is, a crystal oscillator with temperature compensation), and is driven by a control signal from the CPU 23. The PLL (Phase Locked Loop) frequency synthesizer (variable frequency divider). It receives 19 signals and produces a reference clock signal. Then, the reference clock signal, the RF filter, and the RF output from the RFAMP 11
After mixing the signal with the first (1ST) MIX circuit 12, only the difference of the frequency spectrum generated by 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 constant clock signal is generated in the VCOIF 18 by using the TCXO or another oscillation circuit, and the clock signal and the first intermediate frequency signal are supplied to the second (2ND) MIX circuit. The signal is mixed again at 14, and the second intermediate frequency signal is taken out through the IF filter and IFAMP 15. Then, the second intermediate frequency signal is subjected to π / 4 shift 4-phase QPSK by the demodulation circuit 16.
Demodulation (that is, quadrature phase displacement, that is, a kind of linear modulation method used in a digital wireless relay method) is performed.
At this time, the IF filter, IFAMP 15, and demodulation circuit 16 also detect the input reception level at the same time.

Then, in the TDMA processing circuit 21, T
DMA processing (time division separation processing) is performed, and the D / A conversion circuit 24 performs ADPC for the audio signal portion.
D / A conversion of M / PCM (PCM is pulse code modulation, ADPCM is adaptive differential PCM) is performed. After that, the audio processing circuit 25 performs amplification and BPF control processing,
Continuing, with the line control circuit 27 (however, in the case of the 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 or an earphone, and speaker output, ringer output, or connection with a telephone line is performed.

A data signal such as a message is also demodulated by the demodulation circuit 16 and then decoded by a data demodulation circuit 22 including a gate array and a DSP (digital signal processor) after passing through a TDMA processing circuit 21. Processing such as error correction is performed by a control signal from the CPU 23. After that, the processed data is stored in the memory (RAM) in the CPU 23, and the CPU 23 performs processing based on the stored data (message or the like).

On the other hand, on the transmitting side, in the case of the base unit, the voice signal from the telephone line and the microphone emitted from the user, and in the case of the handset the voice signal from the microphone emitted from the user, The line control circuit 27 converts the signal into an electric signal, and the ADPCM / PCM A / D conversion circuit 30 digitizes the signal. For data such as messages, the CPU 23 controls various tables in the memory (RAM) to perform code conversion and error correction in the data modulation circuit 28. Then, the digitized data of voice and data is further subjected to TDMA processing by the TDMA processing circuit 29, and then modulated and π / 4-shifted 4-phase QPSK modulation is performed by the 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 RFAMP 32 and the power is amplified.
After that, 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, and in the DTMF generating circuit 26, DTMF is generated by an instruction from the CPU 23.
Signals and melodies are generated.

[0011]

By the way, in the above-mentioned digital cordless telephone, it is possible to communicate with the partner station indoors through the master unit and outdoors through the public base station, and the parent station is also available. The antenna power of the device 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.

Therefore, in particular, when used outdoors, the slave unit needs to be located within the communication zone of one public base station, and the power level of the slave unit is constant. Therefore, of course, the reception level is affected by the communication distance with the public base station, and is considerably affected by the deterioration of the radio wave condition due to the building or the like. Furthermore, when the slave unit leaves the communication zone of one public base station or when asynchronous interference occurs during standby,
Communication will be difficult unless the process of switching the channel and shifting the communication zone is performed.

As described above, in the slave unit, immediately after the power is turned on,
Alternatively, during standby, it may be difficult to communicate with the public base station or the base unit due to the various causes described above. If such a state is temporary, it does not cause any problem, but if it continues, electric power is wastefully consumed. As a result, the life of the installed battery may be shortened, and the transmission / reception performance may be deteriorated at an early stage.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a digital cordless telephone device having a function of saving a battery mounted therein.

[0015]

In order to achieve the above-mentioned object, the invention according to claim 1 communicates with a partner communication station via a master unit or a public base station of a destination by wireless communication. A digital cordless telephone device having a possible slave unit, whether the slave unit receives broadcast channel information transmitted from the master unit or the public base station when the power is turned on or the call is disconnected. Determination means for determining, and power-off means for cutting off the power supply to the device,
And a power-off control unit that drives the power-off unit to turn off the power when the determination unit determines that the broadcast channel information is not received.

In the invention according to claim 2, the power-off control means further comprises first and second timers for measuring a predetermined time, and a warning sound generator, and the determination means is When it is determined that the broadcast channel information is not received, the first timer and the second timer are started, and the warning sound generator is driven to warn at the same time when the first timer finishes timing. It is characterized in that a sound is generated, and then the power supply disconnecting means is driven to disconnect the power supply at the same time when the second timer finishes timing.

[0017]

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

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 giving a warning that communication is difficult. However, in such a case, the power-off control is performed as follows. That is, if it is determined that the broadcast channel information is not received, the first and second
The respective time counting operations of the timer are started. And
At the same time as the timing operation of the first timer ends, the warning sound generator is driven to generate the warning sound. After that, at the same time when the time counting operation of the second timer ends, the power supply disconnecting means is driven to disconnect the power supply.

As a result of the above, when the portable device is carried and the power is turned on for communication, or when communication is difficult, such as when the call is disconnected, the portable device is carried. A person is warned of this and the power supply to the device is cut off, so that useless power consumption is avoided.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An 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 the digital cordless telephone device according to the present invention is used. As shown in the figure, an indoor parent device P is installed indoors, and a mobile child device PS that can be taken out and moved outdoors is within a communicable area X surrounded by a broken line in the figure.
Communication with the indoor base unit P is possible. Further, an outdoor base station CS is installed outdoors, and the mobile device PS can communicate with the outdoor base station CS within a communicable area Y surrounded by a dashed line in the figure. Furthermore, in this example,
The indoor master device P exists in the communicable area Y of the outdoor base station CS, and the mobile slave device PS can communicate with both the indoor master 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 modulation / demodulation unit 3, a digital signal processing unit 4, an audio signal processing unit 5, and 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,
The warning sound generating section 7, a power switch 8, and a power source section 9 are included.

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

On the other hand, the control unit 6 receives various control data extracted by the digital signal processing unit 4 at the time of reception. Further, at the time of transmission, the control data is output to the digital signal processing unit 4. Further, the control unit 6 includes the RF / IF unit 2
The electric field strength data of the received radio wave from is also input. Further, when communication with the public base station or the base unit is difficult, the control unit 6 drives the warning sound generating unit 7 when the timer A has timed out for a predetermined time to generate a warning sound. After that, when the timer B times out for a predetermined time, the power switch 8 is driven to cut off the supply of power from the power supply unit 9 to each unit.

FIG. 3 is a flow chart showing the processing in the case where communication with the public base station or the base unit becomes difficult during standby, and specifically, one of the control units 6 in FIG. It is a flowchart showing a control operation. Generally, in a cordless telephone device slave unit, when a communication channel is released immediately after power is turned on or when a call is disconnected (including abnormal disconnection due to channel switching failure), a so-called standby state is entered. In this state, the slave unit starts scanning the BCCH (which is a slot having information about the superframe, that is, broadcast channel information) transmitted from the public base station or the master unit.

Therefore, in the digital cordless telephone apparatus according to the present invention, it is determined based on the electric field strength data whether or not the broadcast channel is synchronized by tuning to the frequency with the maximum input level (S1). Then, if the synchronization cannot be achieved (No in S1), the timer A and the timer B set to the predetermined time are started to measure time (S2). Here, the set time of the timer B is set longer than the set time of the timer A. Then, it is confirmed whether or not the timer B has timed out (S3), and when it has timed out (Yes in S3), the power supply 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). If the timer A has timed out (Yes in S5), Drives the warning sound generator 7 to send a warning sound (S6). If the time-out 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 out (S7). Then, when the warning sound is transmitted (Yes in S7),
The generation of the warning sound is stopped by the warning sound generation unit 7 (S
After 8), and when the warning sound is not transmitted (No in S7), the timer A and the timer B are immediately set to their respective initial values (S9), and PCH (necessary for incoming call) (A slot having different information) is executed (S10). After that, if the user goes out of the communication range or loses synchronism during the execution of the standby processing routine, the process returns to step S1.

[0028]

As described above, according to the present invention, when the slave unit is in a state in which 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, effectively saving battery power consumption. In addition, it is possible to prevent the user from forgetting to turn off the power by generating a warning sound to warn that the communication is difficult before turning off the power, and economically operate the digital cordless telephone system.

[Brief description of 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 showing a process in a case where 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]

 1 antenna 2 RF / IF unit 3 modem unit 4 digital signal processing unit 5 audio signal processing unit 6 control unit 7 warning sound generating unit 8 power switch 9 power supply unit A timer B timer P master unit PS slave unit CS public base station X parent Machine communication zone Y Public base station communication zone

Claims (2)

[Claims] 1. A digital cordless telephone device having a slave unit capable of communicating with a partner communication station via a master unit or a public base station of a destination by wireless communication, wherein the slave unit is a power source. Determining means for determining whether or not the broadcast channel information transmitted from the master unit or the public base station is received at the time of turning on or disconnecting the call; and a power source disconnecting unit for disconnecting power supply to the device, A digital cordless telephone device, comprising: a power-off control means for driving the power-off means to turn off the power when the determination means determines that the broadcast channel information has not been received. 2. The power-off control means further includes first and second timers for measuring a predetermined time, and a warning sound generator, and the determination means receives the broadcast channel information. If it is determined that there is not, the first timer and the second timer are started, the warning sound generator is driven to generate a warning sound at the same time when the time counting of the first timer is finished, and then the first sound is generated. 2. The digital cordless telephone device according to claim 1, wherein the power supply disconnecting means is driven to disconnect the power supply at the same time when the timer of 2 is finished.