JP2002325130A - Cordless handset of party telephone set - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a party telephone set that can reduce distortion in a voice signal from a speaker in the case of loudspeaking reception. SOLUTION: When a cordless handset 100 is placed on a charger 200, a voltage (e.g. 5.0 [V]) from a charging terminal 210 of the charger 200 drives a power amplifier 140 so that the voice signal from the power amplifier 140 is not clipped in loudspeaking reception. When the cordless handset 100 is not placed on the charger 200, a voltage (e.g. 2.8 [V]) from a secondary battery 187 drives the power amplifier 140.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a handset of a parent-child telephone having a rechargeable battery.

[0002]

2. Description of the Related Art A typical cordless telephone device comprises a master unit connected to a line and a slave unit wirelessly connected to the master unit.

[0003] The slave unit is usually provided with nickel-
Equipped with a secondary battery made of cadmium, when the user performs a call, the slave unit is operated by the power from the secondary battery, while the slave unit is charged when the secondary battery is charged. The charging operation was performed by placing it in a container.

Also, in a cordless telephone, a voice signal of the other party is transmitted at a high output from a speaker while the slave unit is left, so that the user can talk with the other party without having the slave unit. To listen to music (loudspeaker reception function)
There are also models having, for example, when the user performs an outside line call using the slave unit or listens to the answering machine message stored in the master unit, the slave unit receives the voice data from the master unit, Using the loudspeaker function, it is possible to transmit the voice or message of the other party from the speaker of the slave unit.

FIG. 3 is a circuit diagram showing a charging portion and a speaker portion of a conventional cordless telephone device.

In FIG. 3, when the slave 1 is placed on the charger 2, the charging terminal 10 of the slave 1 is connected to the charging terminal 20 of the charger 2.

One of the charging terminals 10 of the slave unit 1 is grounded, and one of the terminals is connected to the protection diode 30, the resistance element 40, and the secondary battery 50 in order from the left side in FIG.

The protection diode 20 is a diode for protecting each circuit inside the slave unit 1 against a sudden change in voltage (or polarity) from the charger.
This is for adjusting the voltage from the charger to a voltage value necessary for charging the secondary battery 50.

The output side of the secondary battery 50 is connected to the power supply terminals of the respective circuits inside the slave unit 1.

A part of the output of the secondary battery 50 is supplied to the power amplifier 60. For example, when performing loudspeaker reception,
The audio signal received from the base unit (not shown) of the telephone device is
The audio signal input to the input terminal of the power amplifier 60 and amplified by the power amplifier 60 is transmitted from a speaker 70 for loudspeaker reception.

The voltage charged in the secondary battery is about 2.8 [V], and the voltage applied from the secondary battery to each circuit in the slave unit 1 and the power amplifier 60 is also about 2.8 [V]. 2.8
[V].

[0012]

FIG. 4 shows an input signal (a) of a power amplifier 60 when a voice signal of a destination is transmitted from a speaker by loudspeaker reception using the slave unit shown in FIG.
And the output signal (b).

When the power amplifier 60 is driven by the driving voltage (2.8 [V]) of the secondary battery 50 when performing the loudspeaker reception using such a slave unit 1, the dynamic range of the power amplifier 60 is increased. Is narrowed to about 2.8 [V], the input audio signal (FIG. 4A) of the power amplifier 60 is output in a clipped state (FIG. 4B).

For this reason, there is a problem that the user cannot hear the voice well when performing the loudspeaker reception.

[0015]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and a slave unit of a parent-child telephone set according to claim 1 has a rechargeable battery. Is a slave unit of the parent-child phone capable of charging the rechargeable battery by electrically connecting the amplifying unit, wherein the slave unit is amplifying means for amplifying a sound signal, and a sound signal from the amplifying means connected to the amplifying means. And a power supply unit for supplying a voltage from the charger at a plurality of different voltage values, and in a state where the rechargeable battery of the slave unit and the charger are connected, The power supply unit supplies a voltage having a first voltage value to the amplifying unit and supplies a voltage having a second voltage value different from the first voltage value to the rechargeable battery.

According to a second aspect of the present invention, a child device of the parent and child telephone is the child device of the parent and child telephone according to the first aspect, and when the rechargeable battery of the child device and the charger are not connected, the power supply means is provided. Supplies the voltage from the rechargeable battery to the amplifying means at the second voltage value.

[0017]

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

In FIG. 1, the control circuit 11 of the slave unit 100
0 is a transmission / reception circuit 12 which controls the following circuits.
Numeral 0 is connected to the antenna 125 and transmits / receives a radio signal to / from a master unit (not shown).

The speech network circuit 130 is connected to the transmission / reception circuit 120, a power amplifier 140 described later, a speaker 161 and a microphone 162, and
Under the control of 0, switching of a communication path, amplification of a signal, and the like are performed.

The power amplifier 140 amplifies a voice signal or a ring tone input from the speech network 130 and outputs the amplified signal to the speaker 150.

The speaker 150 transmits a voice signal and a ring tone during charging, and the speaker 161 outputs a voice signal of the calling side during a normal call without using the loudspeaker reception when not charging. Microphone 162 inputs voice uttered by the user during a call.

The input unit 170 has a numeric keypad, a call key, and the like. In the present embodiment, the speaker 1 uses a loudspeaker reception function.
When listening to the requirement message from 50, the user can instruct fast-forward or rewind operation of the requirement message by operating the ten keys (for example, 1 and 3).

The power supply circuit section 180 is a circuit for supplying power to the slave unit 2 and has the following configuration.

One of the charging terminals 181 of the slave unit 100 is grounded, and one of the terminals is branched into the anode side of the protection diode 182 and the resistance element 183 in order from the left side in FIG. 183 is connected to a resistance element 184 whose one terminal is grounded.
83 and 184 are FETs (Field Effect T).
(transistor) 185 is connected to the gate side G.

Further, on the source side S of the FET 185,
A secondary battery 186 is connected, a drain side D of the FET 185 is connected to a cathode side of the protection diode 182, and a resistance element 187 is connected between a drain side and a source side of the transistor 185. I have.

Further, the cathode side (the drain side of the FET 185) of the protection diode 182 is connected to the power input terminal of the power amplifier 140,
The source side of 185 (the positive side of the secondary battery) is connected to a power input terminal (not shown) of each circuit.

The resistance value of the resistance element 183 is equal to the resistance value of the resistance elements 184 and 187 (for example, several hundred ohms).
(Eg, several tens of kiloohms).

The charger 200 converts an AC current used at home into a DC current, and
A current can be output from 0 to the charging terminal 181 of the slave unit 100.

Next, the operation of the present embodiment will be described below.

First, when the slave unit 100 is not mounted on the charger 200, current flows from the secondary battery 186 to the power supply terminal of each circuit, and also flows into the source side S of the FET 185. Therefore, a potential difference occurs between the gate side G and the source side S of the FET 185, and the current from the secondary battery flows into the power amplifier 140 via the source S, the gate G, and the drain D of the FET 185.

At this time, the dynamic range of the power amplifier 140 is 2.8 [V] as shown in FIG. 4B, but when the slave 100 is not mounted on the As long as a normal call is made using the microphone 161 and the microphone 162, no distortion occurs in the audio signal transmitted from the speaker 150.

As described above, handset 100 is connected to charger 200
In a state where the secondary battery 186 is not mounted thereon, it is driven by the electric power stored in the secondary battery 186.

On the other hand, when the slave unit 100 is mounted on the charger 200, the current from the charger 200 is supplied to the power amplifier 140 through the protection diode 182 and the resistance element 187 side (the FET 185). (Drain side). At this time, since the resistance value of the resistance element 183 is a high resistance value of several tens of kiloohms,
No current flows into the gate side of the FET 185 and the FET 185
Between the source S and the drain D. Therefore, the current from the charging terminal 181 is
7, and flows into the secondary battery 186.

At this time, a voltage of about 5.0 [V] is applied to the power amplifier 140, and the dynamic range (the value of VL to VH in FIG. 2B) of the power amplifier 140 is about 5.0. [V].

The voltage (about 5.0 [V]) from the charger 200 is charged by the resistance element 187 connected to the cathode side of the protection diode 182 (about 2.8). [V]), and a voltage of about 2.8 [V] is applied to the secondary battery 186 connected to the resistance element 187 and the power input terminal of each circuit.

In this state, the control circuit 110 controls the input unit 1
When a signal indicating an instruction to listen to a business message stored in a master unit (not shown) is detected from 90, the transmission / reception circuit 1
By controlling 20, the transmission / reception circuit 120 instructs the parent machine to transmit the message data stored in the parent machine.

Subsequently, the control circuit 110 sends a signal indicating reception of message data from the master unit to the transmission / reception circuit 12.
When it is detected from 0, by controlling the speech network circuit 130, a communication path is formed between the transmission / reception circuit 120 and the power amplifier 140, and the transmission / reception circuit 12
0 is received in the message data (for example, FIG. 2
(A) is input to the power amplifier 140.

At this time, since the dynamic range of the power amplifier 140 is about 5.0 [V] as described above,
As shown in FIG. 2B, the audio signal input to the power amplifier 140 is output from the speaker 150 without clipping.

When a voice signal from a destination connected to the line is received via the master unit, the voice signal can be similarly output from the speaker 150 using the loudspeaker reception function.

As described above, in the apparatus of this embodiment, when the slave unit 100 is placed on the charger 200, a voltage of about 5.0 [V] is input to the power amplifier 140. Can have a wide dynamic range. For this reason, when the slave unit 100 is placed on the charger 200, even if the audio signal received from the master unit is output from the speaker 150 using the loudspeaker reception function, no distortion occurs in the audio signal.

In this embodiment, the cordless telephone device has been described, but a secondary battery in the device is charged by placing the device on a charger such as a portable telephone device wirelessly connectable to a base station. The present invention can be implemented by applying the present invention.

In this embodiment, the voltages supplied to the power amplifier and the secondary battery are about 5.0 [V] and about 2.8 [V], respectively.
However, the voltage value is not limited to this.

Further, in this embodiment, the FET 185 is used as the switch circuit of the power supply circuit 180. However, another switch circuit such as a switch circuit using a bipolar transistor or the like may be used.

[0044]

The communication apparatus according to the present invention prevents distortion of a voice signal output from a speaker when a loudspeaker operation is performed.

[Brief description of the drawings]

FIG. 1 is a block diagram of an embodiment apparatus to which the present invention is applied.

FIG. 2 is a diagram showing a dynamic range of a power amplifier 140 and an input signal.

FIG. 3 is a circuit diagram of a conventional slave unit.

4 is a diagram showing a dynamic range and an input signal of the power amplifier 50 shown in FIG.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 slave unit 140 power amplifier 180 power supply circuit section 182 protection diode 183 resistance element 184 resistance element 185 FET 186 secondary battery 187 resistance element 200 charger

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04M 1/725 H04B 7/26 LF term (Reference) 5G003 AA01 BA01 CA14 DA07 5K027 AA12 BB03 DD14 GG04 HH01 5K067 AA23 BB04 BB08 EE00 EE02 FF25 FF31 FF38 KK00

Claims (2)

[Claims] 1. A handset of a parent-child phone having a rechargeable battery and capable of charging the rechargeable battery by electrically connecting the rechargeable battery and a charger, wherein the handset amplifies a sound signal. Amplifying means, a signal output means connected to the amplifying means and outputting a sound signal from the amplifying means, and a power supply means for supplying a voltage from the charger at a plurality of different voltage values, In a state where the rechargeable battery of the slave unit and the charger are connected, the power supply unit supplies a voltage having a first voltage value to the amplification unit, and a second voltage different from the first voltage value.
A child device of a parent-child telephone, which supplies a voltage having a voltage value of (i) to the rechargeable battery. 2. The child device of the parent-child telephone set according to claim 1, wherein in a state where the rechargeable battery of the child device and the charger are not connected, the power supply means outputs the voltage from the rechargeable battery to the power source. A child device of a parent-child telephone, wherein the child device is supplied to the amplification means at a second voltage value.