JPH07143548A - Cordless telephone system - Google Patents

Abstract

PURPOSE:To enable speaking with satisfactory voice quality by changing a channel to another speaking channel to perform clear speaking without any noises of beat tones in an audible range before connecting a master station and a hand set through a ratio channel. CONSTITUTION:A noise comparator circuit 21 compares a reference noise level (threshold value) with a received signal noise level inside the audible range (f=300Hz-3KHz) from a receiver amplifier circuit 16 and when the received signal noise level is lower, the speaking channel of a received signal is decided for speaking. When the received signal noise level is higher than the reference noise level (threshold value) inside the previously set audible range, an MPU 23 controls a synthesizer 22 to select another speaking channel different from the speaking channel of the received signal, and the clear speaking channel without any noises of beat tones in the audible range is set by transmitting the speaking channel at this controlled frequency.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a communication channel (C) which is set prior to connection by a wireless line between a master unit and a slave unit.
H) relates to a cordless telephone device that changes to another communication channel when the noise level is high.

[0002]

2. Description of the Related Art Conventionally, in a cordless telephone apparatus of this type, in a wireless connection between a master and a slave, when the slave goes off-hook and sends a call signal to the master, the master in a standby state The calling signal from the slave is detected and a calling response signal is sent to the slave. When the master unit detects a call signal from the line, it sends an incoming call signal to the slave unit, and when the slave unit detects an incoming signal, it sends an incoming call response signal to the master unit. This series of procedures is usually performed on the control channel (CH), and the speech channel (CH) to be used in this procedure is determined. The operation until the radio wave of the call channel (CH) in this case is converted into the received voice signal will be described.

FIG. 3 is a block diagram mainly showing the configuration of a receiving baseband section provided in one or both of a slave unit and a master station of a conventional cordless telephone system. In FIG. 3, this example is provided with a preamplifier circuit 1 for amplifying an FM modulated signal demodulated by a receiver (not shown) and a bandpass filter (BPF) 2 for extracting only an audible region signal. Further, there are provided a de-emphasis circuit 3 for attenuating the high frequency band in the audible range signal from the BPF 2 and an expander 4 for expanding the fluctuation of the signal level from the de-emphasis circuit 3 to a predetermined multiple. . In addition, in this example, a main amplifier circuit 5, a receiver amplifier circuit 6 that amplifies a voice signal to a receiver of a handset (handset), and a receiver 8 that outputs a voice signal from the receiver amplifier circuit 6 as a voice signal. It is provided.
The preamplifier circuit 1 to the receiver amplifier circuit 6 are reception baseband units.

Next, the operation of this conventional configuration will be described. In FIG. 3, the determined radio wave of the communication channel is input to the preamplifier circuit 1 as an FM-modulated demodulation signal and amplified. The frequency of the telephone call, that is, the frequency band of 300 Hz to 3 KHz in the audible range is extracted from the amplified signal through the BPF 2.
The audible area signal from the BPF 2 attenuates the high frequency by the de-emphasis circuit 3, and the expander 4 doubles the level fluctuation of the audio signal by a logarithmic ratio. The audio signal from the expander 4 is amplified by the main amplifier circuit 5. Further, it is differentially amplified by the receiver amplifier circuit 6, and this amplified signal is output from the receiver 8 as audible received voice.

[0005]

However, in the conventional cordless telephone device, when a call channel is determined, a radio wave corresponding to the call channel is received and there is no received voice signal in the received signal. The noise included in the FM demodulated signal is input to a band separation filter (f = 10 KHz) (not shown) provided in the preceding stage of the reception baseband unit, and a full-wave rectified value and a preset value are set. By comparison, the presence / absence of a carrier is determined by this comparison to confirm the availability of a communication channel. In this case, noise cannot be detected in the audible area (f = 300 Hz to 3 KHz) of the call channel. Therefore, there is a problem that a noise of a single frequency component such as a beat sound is generated during a call and the call is disturbed.

In order to solve such a problem, the present invention enables a clear call without noise of the beat sound in the audible region prior to the connection between the master station and the slave unit by a wireless line. It is an object of the present invention to provide an excellent cordless telephone device that can make a call with good sound quality by changing to a channel.

[0007]

In order to achieve the above object, the cordless telephone apparatus according to claim 1 is set up for a call prior to connection of a wireless line between a wireless master device and a wireless slave device. A signal conversion processing means for converting the received signal of the channel into an audible audio signal, a comparison means for comparing the noise level superimposed on the audible audio signal from the signal conversion processing means with a preset reference noise level, and a comparison means. When the noise level of the audible audio signal is higher than the reference noise level,
The communication channel setting control means performs control to change to another communication channel.

According to another aspect of the cordless telephone apparatus of the present invention, the speech channel setting control means and the speech channel generation means for generating speech channels of a plurality of frequencies and the noise level of the audible voice signal from the reference noise level by the comparison means. When the value is high, the communication channel generation means is provided with a communication channel setting control means for controlling transmission of a frequency signal of another communication channel.

[0009]

With such a configuration, the cordless telephone apparatus according to the first and second aspects of the present invention uses the control channel to transmit the outgoing / incoming call signal or the like prior to the connection of the wireless line between the wireless master unit and the wireless slave unit. When the noise level of the audible voice signal of the communication channel set after the execution is higher than the reference noise level, the determined communication channel is changed to another communication channel. Therefore, it is possible to change to a communication channel that allows clear communication without beat noise in the audible region, and it becomes possible to perform communication with good sound quality.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a cordless telephone device of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of an embodiment of a cordless telephone device of the present invention. In FIG. 1, this example is mainly composed of a reception baseband unit provided in one or both of a slave unit and a master station of a cordless telephone device, and a front end for amplifying an FM modulation signal demodulated by a reception unit (not shown). An amplifier circuit 11 and a bandpass filter (BPF) 12 that extracts only an audible region signal from the FM modulated signal from the preamplifier circuit 11 are provided. Further, a de-emphasis circuit 1 for attenuating the high frequency band in the audible range signal from the BPF 12.
3 and an expander 14 for expanding the fluctuation of the signal level from the de-emphasis circuit 13 to a predetermined multiple,
The main amplifier circuit 15 is provided. In this example, a receiver amplifier circuit 16 that amplifies a voice signal to a receiver of a handset (handset), a receiver 18 that outputs a voice signal from the receiver amplifier circuit 16, and a receiver amplifier circuit 16 and a receiver 18 Is provided between
A noise comparison circuit 21 for comparing the noise of the received signal with a reference noise level within a preset audible region, a synthesizer 22 for generating and transmitting a speech channel of a plurality of frequencies, the synthesizer 22 and the noise comparison circuit. Two
Microprocessor (MPU) 23 for controlling the operation of 1
And are provided. In this configuration, the preamplifier circuit 11 to the receiver amplifier circuit 16 are the reception baseband unit.

Next, the operation of this embodiment will be described. FIG. 2 is a flowchart showing the processing procedure of the operation of this embodiment. In FIG. 1 and FIG. 2, the connection process of the wireless line between the master unit and the slave unit is performed by a control channel having a frequency different from the call channel (CH), and the call channel to be used is determined (step (in the figure, , S) 1). The received radio wave of the channel is demodulated by FM detection and input to the preamplification circuit 11 as a demodulation signal to be amplified.

The amplified signal from the preamplifier circuit 11 is B
300 Hz to 3 KH in the audible range through PF12
Extract the z frequency band signal. The frequency band signal in the audible range (300 Hz to 3 KHz) extracted by the BPF 12 is input to the de-emphasis circuit 13, and the high frequency band of the frequency band signal is attenuated. Furthermore, the signal from the de-emphasis circuit 13 is expanded by an expander 14 to double the level fluctuation of the audio signal in a logarithmic ratio. Expander 14
These audio signals are input to the main amplifier circuit 15 and amplified. The audio signal from the main amplifier circuit 15 is differentially amplified by the receiver amplifier circuit 16 in the audible region (f = 30).
The received signal within 0 Hz to 3 KHz is the noise comparison circuit 2
Input to 1. A reference noise level (threshold value: L1) in the audible region is set in advance in the noise comparison circuit 21, and the reference noise level (threshold value: L1) and the audible region from the receiver amplification circuit 16 (f = 300Hz ~
A comparison is made with the received signal noise level (L2) within 3 KHz (steps 2 and 3). By this comparison, when noise such as a beat sound is not generated in the differentially amplified received signal from the receiver amplifier circuit 16 (step 3: No), the noise value is lower than the preset reference noise level. It is processed (step 4). That is, a process of determining the call channel of the received signal for a call is performed (step 5). If noise such as a beat sound is generated in step 3 (Yes), that is, the received signal noise level (L2) in the audible area from the receiver amplifier circuit 16 is a reference within a preset audible area. It is processed as a noise value higher than the noise level (threshold value: L1) (step 6). MPU23
The MPU 23 takes in the comparison value which is the low noise value processing in step 4 and the high noise value processing in step 6. MP
When the high noise value processing in step 6 is incorporated, U23 controls the synthesizer 22 so as to select a communication channel different from the communication channel of the received signal, and transmits the communication channel of this controlled frequency (step 7).

As described above, according to this embodiment, the reference noise level (threshold value: L1) in the audible region preset by the noise comparison circuit 21 is compared with the noise level of the received voice, and the received voice is compared. It is possible to set other call channels that do not generate noise such as beat sounds when the noise level of is high.

[0014]

As is apparent from the above description, the cordless telephone device according to the first and second aspects of the present invention, such as an incoming / outgoing call signal, prior to the connection of the wireless line between the wireless master device and the wireless slave device. When the noise level of the audible voice signal of the speech channel set after the transmission by the control channel is higher than the reference noise level, the determined speech channel is changed to another speech channel, so that There is an effect that it is possible to change to a communication channel that allows clear communication without beat noise and enable communication with good sound quality.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of a cordless telephone device of the present invention.

FIG. 2 is a flowchart showing a processing procedure of an operation of the embodiment.

FIG. 3 is a block diagram mainly showing a configuration of a reception baseband unit provided in one or both of a slave unit and a master station of a conventional cordless telephone device.

[Explanation of symbols]

 12 BPF 13 De-emphasis circuit 14 Expander 16 Receiver amplification circuit 18 Receiver 21 Noise comparison circuit 22 Synthesizer 23 MPU

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location H04M 1/00 N 7304-5K H04B 7/26 109 D

Claims (2)

[Claims] 1. A signal conversion processing means for converting a reception signal of a set communication channel into an audible voice signal prior to connection of a wireless line between a wireless master device and a wireless slave device, and the signal conversion processing device. Comparing means for comparing the noise level to be superimposed on the audible voice signal from the reference noise level set in advance, and when the noise level of the audible voice signal is higher than the reference noise level by the comparing means, to another call channel A cordless telephone device, comprising: a call channel setting control unit that performs a change control. 2. The speech channel setting control means, the speech channel generation means for generating speech channels of a plurality of frequencies, and the speech channel generation when the noise level of the audible voice signal is higher than the reference noise level by the comparison means. 2. A cordless telephone device according to claim 1, further comprising a speech channel setting control means for controlling the transmission of a frequency signal of another speech channel from the means.