JPH01309531A - Radio telephone system - Google Patents

Abstract

PURPOSE:To improve the S/N of a speech signal and to improve the quality of a speech voice by providing a compander circuit to each channel of a radio telephone set and a connection device respectively and providing additionally a control means for line state to the connection device and using the control means so as to set the compander circuit in the non-inserting state at extension talking. CONSTITUTION:Compander circuits 81, 72 are provided respectively to each channel of the radio telephone set and the connection device, and a control means 601 of line state is provided to the connection device and the compander circuits 81, 72 are set in the non-inserting state to a channel by means of the control means 601 at extension talking. As a result, since the speech signal passes just through the compander circuits 81, 72 in the connection device at extension call, the speech signal is sent while being subject to compression processing by a compressor circuit 81 of a radio telephone set even in a radio section also in a wired section from the connection device reaching other connection device via a master set at the extension call. Thus, even if any external noise invades in the wired line between the connection devices, the effect is reduced to improve the S/N of the speech signal. Thus, the communication with high quality is attained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Purpose of the Invention (Field of Industrial Application) The present invention relates to a wireless telephone device used in offices, businesses, etc.

(Prior Art) In recent years, some wireless telephone devices have been designed to allow not only external phone calls but also internal phone calls between a plurality of wireless telephones. Figure 2 shows an example of its configuration.
This device includes a plurality of wireless telephones 11 to 1n, a plurality of connection bags W21 to 2m connected to each of these wireless telephones 11 to 1n via a wireless line, and a plurality of subscriber lines 41 to 1n.
The main unit 30 is configured with a main unit 30 incorporating a

Among these, first of all, the wireless telephones 11 to 1n are equipped with a control circuit (CO
NT) 50, and the control circuit 50 connects the connection devices 21 to 2m when making and receiving calls. Ir1l a.

During a call, a call signal input from a microphone 5 as a transmitter is modulated by a transmitting circuit (TX) 52, and then sent to a wireless line via an antenna 54 via a hybrid circuit 53, and arrives via the wireless line. The received call signal is received by a receiving circuit (RX) 55 via an antenna 54 and a hybrid circuit 53, and the received call signal obtained thereby is output from a speaker 56 serving as a receiver. In addition, 57 is a dial key, 58.
59 is a switch for forming a communication path.

The connection devices 21 to 2m have a control circuit (
CONT) 60 connects the wireless telephones 11 to 1n and the main device 3.
Make a connection between 0 and 0. During a call, a call signal that arrives from the wireless telephones 11 to 1n via a wireless line is received by a receiving circuit (Rx) 63 via an antenna 61 and a hybrid circuit 62, and then this call signal is transmitted to a 2-wire 4-wire It outputs the call signal to the main device 3o via the conversion circuit 64, and also introduces the call signal sent from the subscriber lines 41 to 4 through the main device 3o via the 2-wire/4-wire conversion circuit 64, and converts the call signal into the main device 3o. The signal is modulated by a transmitting circuit (Tx) 65 and sent from an antenna 61 to a wireless line. Note that 66 and 67 are switches for forming a communication path.

The main device 30 includes a crosspoint switch 31 and a control circuit (CONT) 32 thereof.

When an outside line connection request arrives from the connection device 21-2m, the connection device and the subscriber lines 41-4 are selectively connected to form an outside line communication path.

Further, when an extension connection request arrives from the connection devices 21 to 2m, an extension communication path is formed by connecting the calling side connection device and the called side connection device in an exchange manner. In addition, 51-5
m is a 2-wire 4-wire conversion circuit.

By the way, in order to ensure good call quality against fading and the like, in radio telephone devices, a compander circuit is generally provided in the communication path between the radio telephone and the connecting device. The compander circuit includes, for example, a compressor circuit that compresses the volume range of audio input to the modulator at a fixed ratio, and an expander circuit that expands the output signal of the demodulator at the same ratio as the compression ratio and reproduces the original audio signal. For example, in FIG. 2, the wireless telephones 11 to 1n and the connecting device 21
Compressor circuit (COM) 7 for each transmitting signal path of ~2m
1.8], and expander circuits (EXP) 72.82 are provided in each receiving signal path of the radio telephones 11 to 1n and the connection devices 21 to 2m. By installing this compander circuit, the call signal is transmitted wirelessly with its volume range compressed.
As a result, the S/N of the call signal sent and received via the wireless line
can be improved.

(Problem to be Solved by the Invention) However, although it is true that S/H in the wireless section can be improved by providing a compander circuit in such conventional wireless telephone devices, the S/H between the connecting device and the main device is It is completely defenseless against induced noise and high frequency noise mixed on the wired line, and especially when the length of the wired line connecting the above-mentioned connection device and the main device is several tens of meters or more, the above-mentioned external noise I didn't like it because the level could be an issue.

Furthermore, when making an extension call, the call signal passes through two compander circuits, which causes deterioration in call sound quality due to the transient response characteristics of these compander circuits.

The present invention focuses on this point, and by adding a simple circuit, it is possible to reduce the noise mixed between the main device and the connecting device, and also to reduce signal deterioration due to the transient response characteristics of the compander circuit during internal calls. This allows the S/S of the call signal to
An object of the present invention is to provide a wireless telephone device that can improve the quality of voice calls by increasing N.

[Structure of the Invention] (Means for Solving the Problems) The present invention provides a compander circuit for each communication path of a wireless telephone and a connecting device, and in addition, a means for controlling line conditions in the connecting device, When making an extension call, the control means sets the compander circuit to a non-inserted state in the call path.

(Function) As a result, at least when making an internal call, the call signal passes through the compander circuit in the connecting device.
The call signal is compressed by the compressor circuit of the wireless telephone and transmitted not only in the wireless section but also in the wired section from the connecting device through the main device to the other connecting device. Therefore, even if external noise enters the wired line between the connecting devices, the effect is reduced and the S/
N can be kept high, thereby making it possible to perform high-quality calls. Further, since the extension call signal passes through only one compander circuit, deterioration of the signal waveform due to the transient response characteristics of the compander circuit is suppressed to a low level, and this also improves the quality of the call signal.

(Embodiment) FIG. 1 shows the configuration of a connection device which is a main part of a radio telephone device in an embodiment of the present invention. In this figure, the same parts as in FIG. 2 are given the same reference numerals and detailed explanations will be omitted.

Externally controlled changeover switches 68 and 69 are provided in the receiving signal path and the sending signal path in the connecting device, respectively.

These changeover switches 68 and 69 are used to switch between insertion and non-insertion of the compressor circuit 81 and expander circuit 72 into the receive signal path and the transmit signal path. Further, the control circuit 600 includes a switching control means 601 in addition to a wireless line connection control means and the like. This switching control means 601 receives an extension connection request from a wireless telephone, and
Accordingly, when forming a communication path between the calling side wireless telephone and the called side wireless telephone, each of the changeover switches 6
A switching control signal is output to 8.69 to switch these changeover switches 68 and 69 to the non-insertion side of the compressor circuit 81 and expander circuit 72.

With such a configuration, if, for example, one of the wireless telephones 11 to 1n shown in FIG. from the wireless telephone 11 to the connection device 21.
As a result, a wireless communication line is formed between the wireless telephone 11 and the connection device 21. When this wireless communication line is formed, the connection device 21 closes the switches 66 and 67 using the control circuit 600 and transfers the dial information sent from the wireless telephone 11 to the main device 30. When this dial information is sent, the main device 30 determines the connection destination using the control circuit 32, and if the wireless telephone of the connection destination is on standby, connects the cross point switch 31 and instructs the connection device 2j to receive a call. Send a signal.

Then, the connection device 2j forms a wireless communication line with the connected wireless telephone 1j by the control circuit 600, then closes the switches 66, 67, and outputs a switching control signal to the changeover switches 68, 69. Then, these changeover switches 68 and 69 are switched to the non-insertion side of the expander circuit 72 and compressor circuit 81. That is, the expander circuit 72 and the compressor circuit 81 are removed from the communication path in the connecting device 2j, and the communication path is set to the through state. Further, the control circuit 600 of the connection device 2J is
When the communication path is completed, an extension call ON signal is sent back to the main device 30. The main device 30 transfers this extension call ON signal to the connection device 21 on the calling side. Then, the connection device 21 on the calling side receives the changeover switch 68 from the control circuit 600.
．． A switching control signal is output to 69, and these changeover switches 68°-9=69 are connected to the expander circuit 72 and compressor circuit 8.
1 to the non-insertion side, thereby removing the expander circuit 72 and compressor circuit 81 from the communication path within the device and setting the communication path to a through state.

Therefore, during an internal call, the call signal is compressed by the compressor circuit 71 of one of the wireless telephones 11 and then sent to the connecting device 21 via the wireless communication line, and then sent to the expander circuit 72 in the connecting device 21. Then, it is sent to the other party's connection device 2J via the main device 30 in a compressed state without being decompressed. In this connecting device 2J as well, the compressor circuit 81 does not perform compression processing, and the signal is sent as it is to the wireless telephone 1j via the wireless telephone line, and is expanded by the expander circuit 82 of the wireless telephone 1j to form the original telephone call signal. and the speaker 56
will be output as audio. Therefore, the call signal is transmitted not only in the wireless section, but also in the section from one connection device 21 to the other connection device 2J via the main device 30, with pressure line processing applied.
As a result, even if induced noise or high-frequency noise enters the wired communication path between the connecting devices, the influence of the noise can be reduced and the S/N ratio of the communication signal can be maintained at a good level. In addition, since only one set of compander circuits is inserted into the extension communication path, deterioration of signal waveforms due to the transient response characteristics of the compander circuit can be suppressed to a low level, making it possible to perform high-quality extension calls. .

It should be noted that the present invention is not limited to the second embodiment.

For example, in the above embodiment, when making an internal call, the call path in the connecting device is switched from the line that includes the Funpanda circuit to the line that does not include the line using the changeover switches 68 and 69 to allow the call signal to pass through. Instead, the compander circuit may be set to a non-operating state to allow the call signal to pass through. In addition, the circuit configuration of the wireless telephone, the connection device, and the main device, the configuration of the means for setting the compander circuit to the non-inserted state, the connection procedure of the extension communication path, etc. may not depart from the gist of the present invention. It can be implemented with various modifications.

[Effects of the Invention] As described in detail above, according to the present invention, compander circuits are provided in each communication path of the wireless telephone and the connecting device, and in addition, a line state control means is provided in the connecting device, During a call, by setting the compander circuit to a state where the compander circuit is not inserted into the call path using the control means described in 1. To provide a radio telephone device which can reduce signal deterioration due to the transient response characteristics of a compander circuit during an internal call, thereby increasing the S/N of a call signal and improving the quality of the call voice. I can do it.

[Brief explanation of the drawing]

FIG. 1 is a circuit block diagram showing the configuration of a connecting device which is a main part of a radio telephone device according to an embodiment of the present invention, and FIG. 2 is a circuit block diagram showing an example of the structure of a conventional radio telephone device. 11-]n...wireless telephone, 21-2n...connection device, 30...main device, 41-4no...subscriber line, 50
．． 60...Control circuit, 51~5m, 64...2-wire 4-wire conversion circuit, 51...Microphone, 52°65...
Transmission circuit, 53.62...Hybrid circuit, 54.
61... Antenna, 55. 63... Receiving circuit, 56
...Speaker, 57...Dial key, 58°59.
66.67... Switch, 68.69... Selector switch, 71.81... Compressor circuit, 72°82
. . . Expander circuit, 601 . . . Switching control means. Applicant's agent Patent attorney Takehiko Suzue

Claims (1)

[Claims] It is equipped with a plurality of wireless telephones, a plurality of connecting devices to which these wireless telephones are connected via wireless lines, and a main device connected to a wired telephone line. In a wireless telephone device that selectively connects a connecting device and a wired telephone line, and selectively exchanges and connects each of the connecting devices in the case of an internal call, each of the plurality of wireless telephones and the connecting device What is claimed is: 1. A radio telephone device, characterized in that each communication path is provided with a compander circuit, and the connecting device is provided with a control means for setting the compander circuit in a non-inserted state with respect to the communication path during an internal call.