JP2894882B2 - Hands-free telephone equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hands-free telephone device, and more particularly, to a hands-free (hereinafter referred to as HF) circuit.
The present invention relates to a configuration of an automobile telephone device or the like.

[0002]

2. Description of the Related Art FIG. 2 is a block diagram showing only a portion related to an HF operation in a conventional mobile telephone device with an HF circuit.

In FIG. 2, reference numeral 2 denotes a switching circuit for switching between a normal communication circuit as a car telephone and the HF circuit 1. The common end of the switching circuit 2 is connected to the output side of the receiving circuit 3 and the input side of the transmitting circuit 4, respectively. The output of the receiving circuit 3 is
Via the switching circuit 2, it is connected to the receiver amplifier 5 that drives the receiver 6. Also, the microphone / amp 8
The input side is connected to the microphone 7, and the output side is connected to the input side of the transmission circuit 4 via the switching circuit 2.

[0006] The receiving input terminal 51 of the HF circuit 1 is connected to the output side of the receiving circuit 3 via the switching circuit 2. The receiving output terminal 52 is connected to the input of the speaker amplifier 9 that drives the built-in speaker 10. The transmission output terminal 62 is connected to the input side of the transmission circuit 4 via the switching circuit 2. or,
The transmission input terminal 61 is connected to the microphone connection jack 12 for HF. Reference numeral 13 denotes a HF microphone presence / absence detection circuit whose output controls the switching circuit 2.

Next, the operation in the normal call and HF call states will be described with reference to FIG.

First, H is connected to the microphone connection jack 12 for HF.
When the microphone for F is not connected, a normal communication state is established, and the switching circuit 2 is connected in the direction of the broken line in FIG. The car-specific device is a built-in microphone 7
And the receiver 6 are used to enable a call. The sound input from the microphone 7 is amplified by the microphone amplifier 8, is input to the transmission circuit 4 via the switching circuit 2, and is transmitted to the other party.

The received signal is supplied from the receiving circuit 3 to the switching circuit 2.
, And is amplified by the receiver / amplifier 5 to drive the receiver 6 to enable a normal call.

Next, H is connected to the microphone connection jack 12 for HF.
When the microphone 21 for F is connected, the detection circuit 13 detects the presence of the microphone for HF, and the switching circuit 2 is connected in the solid line direction in FIG. All the transmission and reception of the car telephone apparatus pass through the HF circuit 1 and the speaker 10 and the HF microphone 21 enter the HF communication state.

The sound input from the HF microphone 21 is
The signal is input to the transmission input terminal 61 of the HF circuit 1 via the HF microphone connection jack 12. The voice output from the transmission output terminal 62 through the HF circuit 1 is input to the transmission circuit 4 via the switching circuit 2 and transmitted.

The received signal is sent from the receiving circuit 3 to the switching circuit 2.
Is input to the reception input terminal 51 of the HF circuit 1 via the. Then, the sound output from the receiving output terminal 52 through the HF circuit 1 is amplified by the speaker amplifier 9 and the speaker 10 sounds to enable HF communication.

[0011]

However, in the above-described conventional configuration, the use of a speaker having a high rating and a high efficiency as the built-in speaker 10 has a physical upper limit due to the recent miniaturization of the device. In order to obtain a sound pressure by selecting a high gain of the speaker / amplifier, there is a disadvantage that sound saturation is likely to occur, and it is difficult to obtain HF characteristics satisfying in sound quality.

For this reason, even if the user desires to use another external speaker having higher sound pressure and speaker efficiency than the built-in speaker 10 at the time of the HF operation, it is not possible to replace the built-in speaker 10 with the built-in speaker 10. Are difficult to achieve.

Therefore, when an external speaker is inevitably used, another HF telephone device in which the use during HF operation is limited to the external speaker in advance and the receiving gain is reduced so that the gain distribution is adapted to the external speaker is provided. Needed to supply. Further, the gain distribution in this case has a disadvantage that the sound pressure is insufficient when the built-in speaker is used.

In view of the above drawbacks, the technical problem of the present invention is to provide an HF telephone device that can obtain acoustically good HF characteristics even when an external speaker is used as well as a built-in speaker. .

[0015]

According to the present invention, there is provided a hands-free telephone device which uses a built-in speaker for receiving a call and a hands-free microphone for transmitting a call, and establishes a hands-free call state. In the hands-free telephone device provided with a receiving circuit for supplying a reception signal to the built-in speaker in the hands-free call state, a hands-free microphone connection terminal to which the hands-free microphone is connected, and an external speaker for receiving A connection terminal for an external speaker, a means for disconnecting the built-in speaker from the receiving circuit when the external speaker is connected to the connection terminal for the external speaker, a hands-free microphone terminal and a connection for the external speaker. Connection state detection means for detecting the connection state of the terminal, and the connection state detection means,
When both the state in which the hands-free microphone is connected to the hands-free microphone terminal and the state in which the external speaker is connected to the external speaker connection terminal are detected, the gain of the receiver circuit is increased. Gain changing means for changing a gain corresponding to the built-in speaker from a gain corresponding to the external speaker to a hands-free telephone device.

Also, according to the present invention, in the hands-free telephone device, the gain varying means may be configured to determine whether the hands-free microphone is connected to the hands-free microphone terminal by the connection state detecting means. When both the state where the external speaker is connected to the external speaker connection terminal is detected, the gain of the receiving circuit is
A hands-free telephone device having a variable gain amplifier for changing a gain corresponding to the built-in speaker to a gain corresponding to the external speaker is obtained.

That is, the present invention relates to a hands-free telephone device comprising a wireless telephone device and a hands-free circuit.
It is configured to include means for detecting that both the hands-free microphone and the external speaker are connected, and varying the gain of the receiver circuit in the hands-free circuit.

[0018]

Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of an HF telephone device according to one embodiment of the present invention. Portions common or corresponding to the conventional example are denoted by the same reference numerals.

The reception output terminal 52 of the HF circuit 1 is connected to the variable gain amplifier 15, and its output is
Connected to. The output of the speaker amplifier 9 is connected to a built-in speaker 10 via an external speaker connection jack 11. A circuit 14 detects that the external speaker 22 is connected to the external speaker connection jack 11 and that the HF microphone 21 is connected to the HF microphone connection jack 12. Is variable.

Here, the operation in the normal communication state is omitted because it is the same as that of the conventional example.
This will be described with reference to FIG.

First, the HF microphone connection jack 12
When the HF microphone 21 is connected, the detection circuit 13 detects the presence of the HF microphone, and the switching circuit 2 is connected in the solid line direction in FIG. Then, the transmission and the reception pass through the HF circuit 1, and the built-in speaker 10 and the HF microphone 21 enter the HF communication state.

Here, since the gains of the variable gain amplifier 15 and the speaker amplifier 9 are determined in advance so as to obtain an optimum gain distribution when the built-in speaker 10 is used, a good HF call can be obtained.

Next, when the external speaker 22 is connected to the external speaker connection jack 11, the output of the speaker amplifier 9 disconnects the built-in speaker 10 and
Connected to. The detection circuit 14 detects both the presence of the external speaker and the presence of the HF microphone,
The gain of the variable gain amplifier 15 is changed so as to obtain an optimal gain distribution when the external speaker 22 is used. As a result, even when the external speaker 22 is used, HF communication with good sound quality can be performed.

Here, a specific embodiment of the detection circuit 14 and the variable gain amplifier 15 will be described with reference to FIG.

The inside of the variable gain amplifier 15 includes the HF circuit 1
And an OP amplifier circuit 32 whose gain is determined by the resistors 41, 42 and 43.

The detection circuit 14 comprises a NOR circuit 33 and bias resistors 44 and 45. The external speaker connection jack 11 uses a stereo jack.

Next, the operation in the HF call state will be described with reference to FIG.

First, when the HF microphone 21 is connected to the HF connection jack 12, one input 35 of the NOR circuit 33 is turned off from the H level because the voltage + V applied through the bias resistor 45 is cut off. Open.

When the built-in speaker 10 is used, the input terminal 34 of the NOR circuit 33 is at the H level because the voltage + V is applied through the bias resistor 44, and the output of the NOR circuit 33 is It becomes L level.

At this time, the analog switch 31 is connected in a solid line, and the gain of the variable gain amplifier 15 is determined by the resistors 41 and 43, and the optimum gain distribution suitable for the built-in speaker 10 is obtained. .

Next, when an external speaker 22 is connected to the external speaker jack 11, the output of the speaker amplifier 9 disconnects the built-in speaker 10 and the external speaker 2
2 is connected. The input terminal 34 of the NOR circuit 33
Is open, so that the output of the NOR circuit 33 becomes H level. At this time, the analog switch 31 is connected in a broken line, and the gain of the variable gain amplifier 15 is determined by the resistors 42 and 43, so that the optimum gain distribution suitable for the external speaker 22 is obtained.

[0033]

As described above, the present invention detects that both the external speaker and the HF microphone are attached, and changes the gain of the receiving circuit in the HF circuit, thereby providing a built-in microphone. Use of any of the speakers and another external speaker has an effect of obtaining acoustically good HF characteristics.

[Brief description of the drawings]

FIG. 1 is a block diagram of one embodiment of the present invention.

FIG. 2 is a block diagram of a conventional example.

FIG. 3 is a specific circuit diagram of a detection circuit 14 and a variable gain amplifier 15 according to an embodiment of the present invention.

[Description of Signs] 1 Hands-free (HF) circuit 2 Hands-free and call switching circuit 3 Receiving circuit 4 Transmitting circuit 6 Receiver (receiver) 8 Microphone amplifier 10 Built-in speaker 5 Receiver amplifier 7 Microphone 9 Speaker amplifier 11 External speaker jack 12 Hands-free microphone jack 13 Hands-free microphone detection circuit 14 Detection circuit for both hands-free microphone and external speaker 15 Variable gain amplifier 21 Hands-free microphone 22 External speaker 51 HF circuit reception input terminal 52 HF Circuit receiving output terminal 61 HF circuit transmitting input terminal 62 HF circuit transmitting output terminal 31 Analog switch circuit 32 OP amplifier 33 NOR circuit 34, 35 NOR circuit input terminal 41, 42, 43, 44, 45 Resistance

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-2-94948 (JP, A) JP-A 1-213056 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H04M 1/60

Claims (2)

(57) [Claims] 1. A hands-free telephone device that uses a built-in speaker for receiving and a hands-free microphone for transmitting, and establishes a hands-free call state. In the hands-free telephone device provided with a receiver circuit for supplying to a built-in speaker, a hands-free microphone connection terminal to which the hands-free microphone is connected, and an external speaker connection terminal to which an external speaker for reception is connected Means for disconnecting the built-in speaker from the receiving circuit when the external speaker is connected to the external speaker connection terminal; and connection state detection for detecting a connection state between the hands-free microphone terminal and the external speaker connection terminal. Means for connecting the hands-free microphone terminal to the hands-free microphone terminal. When both the state where the external microphone is connected and the state where the external speaker is connected to the external speaker connection terminal are detected, the gain of the receiving circuit is changed from the gain corresponding to the built-in speaker to the external level. A hands-free telephone device comprising: gain changing means for changing a gain corresponding to a speaker. 2. The hands-free telephone device according to claim 1, wherein said gain varying means includes a state in which said connection state detecting means connects said hands-free microphone to said hands-free microphone terminal and said external speaker. Variable gain amplifier that changes the gain of the receiving circuit from a gain corresponding to the built-in speaker to a gain corresponding to the external speaker when both the state where the external speaker is connected to the connection terminal are detected. A hands-free telephone device comprising: