JPS6226966A - Loudspeaker type simultaneous talking device - Google Patents

Abstract

PURPOSE:To attain talking with high quality talking without displeasant side tone and unnatural feeling by inserting a filter having a characteristic reducing high frequency component in response to the increase in the voice input to a transmitter of the 1st transceiver between the 2nd transceiver and the 1st transceiver. CONSTITUTION:The voice inputted to a transmitter 6 is sent to the 2nd transceiver 2 and a voice output is obtained from a receiver 7 and its output is inputted to a transmitter 4 as a side tone. On the other hand, the output is inputted to a transmitter 4 as a side tone. On the other hand, an output of the receiver 7 is detected by a receiver output detection circuit 10, the detected output is fed to a transistor 16 of a detection output filter 3, the the filter 3 is activated and a high frequency component flows through the filter 3. Thus, the high frequency component of the side tone by the receiver inputted to the transmitter 4 is reduced, displeasant high frequency component due to distortion of an amplifier is excluded and the human voice returns to the own receiver 5 as it is as the side tone, unnatural feeling is eliminated and talking with high quality is attained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a loudspeaker simultaneous call device that improves call quality.

[Conventional technology] Conventional loudspeaker simultaneous call devices are equipped with an AGC circuit, which causes the sidetone volume to fluctuate over the entire audio input band to the handset, and when the 800 circuit starts and stops operating. It was sometimes jarring, especially when the person on the other end spoke loudly and the high-frequency components due to amplifier distortion returned as sidetone, which was felt as a very harsh sound and was unpleasant. [Problem that the invention seeks to solve]

As a method for solving the above-mentioned problems, Tomotoe suggests that if a howling prevention circuit is provided as shown in Japanese Utility Model Publication No. 57-33667, the above-mentioned unpleasant side sounds can be reduced. However, if you do this, the sound corresponding to the audio input level will not be returned as sidetone, so for example,
Even if the speaker speaks loudly, the voice is returned at the same volume, resulting in an unnatural sound and a deterioration in the quality of the call.

[Means for solving problems]

The present invention has been made in view of the above-mentioned circumstances, and has the following features: 1. Remove the side effects of harsh high-frequency components; The purpose of the present invention is to provide a loudspeaker simultaneous communication device.

The loudspeaker simultaneous conversation device of the present invention provides a connection between a first transmitting/receiving device and a second transmitting/receiving device [2. It is characterized in that a filter is inserted which has a characteristic that high-frequency components decrease as the audio input to the transmitter of the first transmitting/receiving device increases.

〔Example〕

il+ is a first transmitting/receiving device, (2) is a second transmitting/receiving device connected to the first transmitting/receiving device (1), and (3) is a transmitter of the second transmitting/receiving device (2). This is a filter inserted between the handset (4) and the handset (5) of the first transmitter/receiver attachment fi1 (11).

The filter (3) has a characteristic that high-frequency components decrease as the audio input to the transmitter (6) of the first transmitting/receiving device (1) increases.

To explain the above embodiment in more detail, the first transmitting/receiving device (1) is a handset type, and the second transmitting/receiving device (2) is of a handset type.
) has a transmitter (4) and a loudspeaker type receiver ('l), and has a loudspeaker type receiver ('l). And, each transmitter (6), (7) of the eleventh second transmitter/receiver device (1), (2), the receiver (4)
) and (5), amplifiers (8) and (9) are inserted between them, respectively. In addition, (1 (g) is a receiver output detection circuit, which has a parallel connection of 17 resistors 0η and a diode Q2
and a capacitor q3 are connected in parallel to the receiver ('γ). Further, a filter (8) is connected to a resistor α4 connected in series to the transmitter (4) and the amplifier (9) of the second transmitting/receiving device 2, and to this resistor a4. The transmitter (4) is connected to the transmitter (4) through a transistor (11 and 1).
are connected in parallel to n. Then, the transistor 06) of this circuit is connected to the output terminal of the receiver output detection circuit 0α, that is, the connection point between the resistor 0° C., the series circuit of the diode OI, and the capacitor 03. I'm here. Note that [7] (formerly known as DC blocking capacitor).

Next, the present invention will be explained in detail. First transmitter/receiver (1
) and the second receiving device (2), simultaneous calls are made between one party and the other party.

Now, if you speak loudly toward the first transmitter/receiver stack, the sound input to the transmitter (6) will be transmitted to the second transmitter/receiver fitting.
+2+, and the audio output is output from the receiver 6 (7). This output is input to the transmitter (4) as sidetone. On the other hand, the output of the receiver ('l) is detected by the receiver output detection circuit 01, and this detection output is applied to the transistor (8) of the filter (8), and the transistor (16) becomes low impedance due to the VC. therefore,
The filter (8) is activated, and the high frequency components are passed through the filter (8) side. At this time transistor a6)
is the linear V-impedance Y depending on the detection level.
ffJ may be changed, or it may be such that a switching action is performed on a constant detection level of R. Therefore, the receiver (
The sidetone caused by
00Hz audio is transmitted with sidetone [7], receiver (5)
1) Removes unpleasant high-frequency components caused by distortion from an expensive amplifier, etc. Human speech has sidetones (7,
Since the call returns to your handset (5), you can expect a high-quality call without any unnatural feeling.

In order to reduce the high-frequency components, in the above embodiment, a method was adopted in which the amount of high-frequency attenuation was increased as the volume increased, but the cutoff frequency was shifted to the low-frequency side as the volume increased. It is also possible to use a method of migration.

However, as the ultimate state of reduction, high frequency components may be removed.

Further, the loudspeaker type is used as the first transmitting/receiving device and the handset type is used as the second transmitting/receiving device, and the filter of the present invention is interposed between the former transmitter and the latter receiver. You may also insert it. In a system in which a filter is inserted, one of them may be used as a first transmitting/receiving device, and the other may be provided with a second. In addition, the 11th and 2nd transmitter/receiver equipment
The present invention is also applied when i is a loudspeaker.1. That's fine.

In addition, Figure 2 shows the change in the volume of the filter 'g'4 +81.
The change in 1/+ is shown in the small-4 diagram.

〔Effect of the invention〕

The present invention has been described above (2).There is a loudspeaker simultaneous telephone call system #sτ between the second transmitting and receiving device and the first transmitting and receiving device. Insertion of a filter that has the characteristic of reducing high-frequency components in response to an increase in the sound input to the transmitter increases the amount of voice input to the transmitter during calls. 7) The sidetone that returns to the receiver has a reduced high-frequency component, which eliminates the harsh unpleasant sensation, and human speech is mixed with that distorted sidetone. Since the call is sent back, the unnatural feeling is eliminated and the call can be made with high quality.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of an embodiment of the present invention, and FIG. 2 is a characteristic diagram of a filter according to the present invention. fll・first transmitting/receiving device if. (2)...Second transmitting/receiving device #, (3)...Filter. .

Claims (1)

[Claims] A first transmitting/receiving device; a second transmitting/receiving device connected to the first transmitting/receiving device; a transmitter of the second transmitting/receiving device; and a filter interposed between the handset of the handset and the receiver, the filter having a characteristic that high-frequency components are reduced in accordance with an increase in audio input to the handset of the first handset and receiver. Simultaneous call intercom device.