JPH05304498A - Stereophonic calling system in php system - Google Patents

Abstract

PURPOSE:To enable stereophonic call mutually between slave units in 'PHP(R)' system composed of a public master unit, respective master units and slave units. CONSTITUTION:The public master unit (public base station) 2 is connected to an ISDN network 1 and the call with a slave units 3 inside the service area of the public master unit 2 is enabled. A stereophonic headphone 4 and a stereophonic microphone 5 constituted integrally are connected to the slave units 3. One carrier frequency is defined as 8 slots, 4 slots T1-T4 and R1-R4 are assigned for transmission and reception and 4 channels are multiplexed, the two channels of the voice signal of 32Kbps for one channel are bundled to be 64Kbps and connected to the B channel of 64Kbps of the ISDN network 1. Thus, the stereophonic call mutually between the slave units 3 is enabled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stereo communication system in a PHP (Personal Handy Phone) system.

[0002]

2. Description of the Related Art In recent years, cordless telephones have rapidly become popular because they have the convenience of being able to make telephone calls at any place such as at home and in urban areas. However, the cordless telephone cannot be used by carrying it outside due to the limit of calls within the service area of the base unit. In addition, the mobile phone can be used not only outside the service area but also at home and in the office.
Since it is originally equipped with a telephone (cordless telephone, etc.) at that place, it cannot be used in a business place or the like, and the usefulness of the mobile telephone itself cannot be exhibited. Furthermore, since the mobile phone has to communicate with an external base station rather than a base unit installed in a home or the like, a radio wave may be difficult to reach in some places, and a call may not be possible.

From such a background, at home, in business establishments,
Furthermore, a PHP system is being considered in which the same portable telephone can be used in urban areas. This is connected to the line by communicating with an individual master unit at home or the like, and by communicating with a public master unit installed in each predetermined area when going out.

By the way, in the conventional analog cordless telephone system, the access method is FDMA.
(Frequency division multiplexing), and the transmission method is FDD (Freque
ncy Division Duplex) has been adopted. The audio transmission system is analog. Depending on the manufacturer, a handset of this analog cordless telephone system can be equipped with headphones and a microphone (integrated type) as an option to make a call.

[0005]

However, it is difficult to improve the transmission speed and the transmission quality in the above analog line. This is because the analog transmission system is vulnerable to external noise and a good quality transmission medium must be used to maintain the transmission quality. Further, in analog transmission, even if headphones and a microphone are used, they are monaural. Two lines must be used to enable a stereo call. SUMMARY OF THE INVENTION It is an object of the present invention to provide a stereo call system in which a handset can perform a stereo call in the PHP system.

[0006]

In order to achieve the above object, a stereo communication method in a PHP system according to the present invention is to communicate with an individual master unit and a public master unit connected to an ISDN network through the master unit. P, which is configured to be capable of making a call through the public master unit when the slave unit goes out of the service area of the individual master unit.
In the HP system, a signal on one carrier frequency is set to 8 slots, 4 slots are allocated for transmission and reception, respectively, and 4 channels are used, 2 channels of which are used for left and right stereo, and carriers are multiplexed for TDMA / TDD. By multiplexing the audio information amount of 32 kbps per channel and 64 kbps of two channels, the I
It is configured to connect to a 64 kbps B channel of an SDN network, and the slave unit includes a circuit for demultiplexing the stereo audio of the left and right channels, a codec circuit for encoding and decoding the left and right channels, and It is configured to include stereo headphones and a stereo microphone connected to the codec.

[0007]

According to the above construction, stereo communication is possible in the PHP system.

[0008]

The present invention will be described in more detail with reference to the drawings. FIG. 1 is a circuit diagram showing an embodiment of a PHP system connected to an ISDN network adopting a stereo communication system according to the present invention. The public base station 2 that constitutes the PHP system is connected to the ISDN network 1. PHP handset 3
Is configured to convert the voice into a digital signal and output the digital signal inside the PHP handset 3 from the other PH.
When a telephone call is made to the P-slave unit, end-to-end digital transmission is performed via the ISDN network 1 and 64 Kbps information can be directly sent.

The PHP system employs 4-channel multiplexing TDMA (Time Division Multiple Access) as an access method and TDD (Time Division Duplex) as a transmission method. In this method, as shown in FIG. 2, a signal on one carrier frequency is set to 8 slots (one frame), and communication from the public base station 2 to the PHP slave unit 3 and communication from the PHP slave unit 3 to the public base station 2 are performed.
4 slots are assigned to each of the communication to and the 4 channels are set bidirectionally. In addition, the audio encoding method is AD
32 Kb of audio information using PCM (adaptive difference PCM)
It is compressed and encoded to ps. 32Kb per channel
The ps audio signal is bundled into two channels and set to 64 Kbps I
It is connected to the 64 Kbps B channel of the SDN network.
The left and right 1 channel 32 Kbps voices are multiplexed by TDMA / TDD using 2 channels and transmitted to the public base station 2.

A stereo headphone 4 and a stereo microphone 5 which are integrally formed are connected to the PHP slave unit 3.
FIG. 3 is a perspective view showing another embodiment of the child device. The child device 6 is an earphone type, and the stereo microphone 7 is provided in an earphone type child device housing 6. A stereo earphone 8 is connected to the child device housing 6 to enable a stereo call.

FIG. 4 is a block diagram showing an embodiment of the circuit of the PHP slave unit. The modulator / demodulator 11 connected to the antenna 10 time-division-multiplexes carrier frequencies or separates time-division-multiplexed carrier frequencies.
The modem 12 modulates the carrier frequency with the digital voice signal or demodulates the modulated carrier frequency to take out the digital voice signal. The demultiplexing circuit 14 is a circuit that separates the demodulated two-channel digital audio signals into left and right, and multiplexes the left and right digital audio signals from the codec circuits 15 and 16. Codec circuit 15
The left voice and the right voice are coded and decoded by the codec circuit 16. When the analog voice signal is input from the microphone A, the speech path 17 connects the analog voice signal to the input of the codec circuit 15. When the analog audio signal from the codec circuit 15 is input, the analog audio signal is sent to the speaker A. The codec circuit 16 operates similarly to the microphone B and the speaker B. Control CPU 13
Controls transmission and reception based on an input instruction from the key circuit 19.

Next, the operation of the handset 3 of FIG. 1 transmitting to another handset to perform a stereo call will be described with reference to FIG. When a telephone number is input by the key circuit 19, the control CPU 13 uses the control channel to transmit the information via the modem 12 and the modulator 11. The public base station 2 secures a communication channel and performs control for connecting to the partner mobile station via the ISDN network. When connected to the other handset, a stereo call is possible with the reserved call channel. The voice that enters the microphone A is input to the codec circuit 15 via the speech path 17. The codec circuit 15 converts the analog voice into an adaptive difference by the ADPCM method, and then P
Convert to CM. As a result, one channel of 32 Kbps digital audio signal is created. The codec circuit 16 also converts the right side audio signal into a digital audio signal of 32 Kbps per channel. Codec circuits 15 and 1
The 6 channels of 32 Kbps digital signal are multiplexed to 64 Kbps by the demultiplexing circuit 14, and the carrier frequency is modulated by the modem 12. The modulated wave is time-division multiplexed by the modulator / demodulator 11 and transmitted from the antenna 10.

On the other hand, the received wave is separated into one modulated carrier wave by the modulator / demodulator 11 and demodulated by the modem 12. 64 Kbp demodulated by modem 12
The digital signal of s is separated into left and right digital audio signals by the demultiplexing circuit 14 and then decoded by the codec circuits 15 and 16, respectively. Codec circuit 1
The analog audio signal output from 4 is from speaker A
The analog audio signals output from the codec circuit 15 are reproduced by the speaker B, respectively, and stereo call becomes possible.

[0014]

As described above, according to the present invention,
This has the effect of enabling stereophonic communication in the PHP system.

[Brief description of drawings]

FIG. 1 is a PH adopting a stereo call system according to the present invention.
It is a schematic diagram for explaining an example of a P system.

FIG. 2 is a diagram for explaining TDMA / TDD4 multiplexing for adopting a stereo communication system according to the present invention.

FIG. 3 is a perspective view showing another embodiment of the PHP system slave unit used in the method of the present invention.

FIG. 4 is a block diagram showing an embodiment of a circuit of a PHP system slave unit used in the method of the present invention.

[Explanation of symbols]

 1 ISDN network 2 public base station (public base unit) 3 PHP handset 4 stereo headphones 5, 7 stereo microphone 6 earphone type handset 8 earphone 10 antenna 11 modulator / demodulator 12 modem 13 control CPU 14 demultiplexing circuit 15, 16 Codec circuit 17,18 Speech path 19 Key circuit

Claims (1)

[Claims] 1. An individual master unit and a public master unit connected to an ISDN network, and a slave unit that makes a call via the master unit, and the slave unit goes out of the service area of the individual master unit. In this case, the PHP system is configured so that the telephone call can be performed via the public base unit, and a signal on one carrier frequency is set to 8 slots, and 4 slots are allocated to transmission / reception, and 4 channels are set. Channels are used for left and right stereo, carriers are multiplexed and multiplexed by TDMA / TDD, and 64 kbps of the ISDN network is obtained by making the audio information amount of 64 kbps for 2 channels at 32 kbps for each channel.
And a circuit for demultiplexing the stereo audio of the left and right channels, a codec circuit for encoding and decoding the left and right channels, and the codec. A stereo communication system in a PHP system, which comprises a stereo headphone and a stereo microphone.