KR950003323B1 - Sidetone level control device - Google Patents

Abstract

The device adjusts side tone level, and reduces the effect of side tone. The device includes a main unit(30), a digital data transmit/receive unit(42), a controller(41) which controls the digital key phone, a signal converter(43) which converts analog signal into B channel data, a receiving amplifier(46), a handset(47), a transmitting amplifier(45), and a side tone level adjuster(44).

Description

Sidetone level adjuster of digital key-phone

1 is a block diagram of a sidetone level adjusting device of an analog key phone according to the prior art.

2 is a block diagram of a sidetone level adjusting device of a digital key phone according to the present invention.

3 is a control flowchart of the present invention shown in FIG.

* Explanation of symbols for main parts of the drawings

41: control unit 42: digital data transmission and reception unit

43: signal converter 44: sidetone level control unit

45: transmit amplifier 46: receive amplifier

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital key phone system, and more particularly, to an apparatus for adjusting a side tone level of a digital key phone, which allows the side tone level to be automatically adjusted regardless of the amount of transmission and reception.

1 is a configuration of a sidetone level adjusting device of an analog key phone according to the prior art.

As shown in FIG. 1, the analog key phone system includes a main device 10 and an analog key phone phone 20, and the analog key phone phone 20 is a transformer for burning a voice signal transmitted / received with the main device 10. 21, an impedance matching circuit 22 for maximizing the transmission characteristics of the transformer 21, and adjusting the phonograph characteristics, and amplifying the audio signal transmitted from the main apparatus 10 through the transformer 21 to the handset 25. A transmission amplifier 23 for amplifying the transmission audio signal from the reception amplifier 24 and the handset 25 for transmission to the main unit 10 through the transformer 21, and the sound signal as an electrical signal. It consists of a handset 25 for changing or for converting an electrical signal into an acoustic signal.

In the process of transmitting the voice signal from the analog key phone 20 of FIG. 1 to the main device 10, the transmission voice signal from the handset 25 is amplified to a predetermined level through the transmission amplifier 23 and then through the transformer 21. The transmission voice signal is transmitted to the main device 10 and fed back to the input of the receiving amplifier 24 through the transformer 21. At this time, the impedance matching circuit 22 adjusts the sidetone level by maximizing the transmission characteristics by matching the impedance of the transformer 21.

In the conventional analog key phone, the impedance matching circuit 21 transmits the voice when the transmitted voice signal from the handset 25 is amplified by the transmit amplifier 23 and then transmitted to the main device 10 through the transformer 21. Since the side tone level of the signal cannot be adjusted accurately, the transmitted voice signal is fed back to the receiving amplifier 24, causing a howling to deteriorate the quality of the call, and the receiving amplifier through the transformer 21 when receiving the voice signal transmitted from the main device 10. The audio signal amplified by the 24 and transmitted to the handset 25 is re-amplified by the transmission amplifier 23 and then fed back to the main device 10 through the main device 10 through the transformer 21 to transmit and receive voice. There was a problem that caused interference between the two sides, and the sidetone level was affected as the amount of transmission and reception was adjusted, making it difficult to adjust the sidetone level to a desired size. .

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and when the voice signal is transmitted through the claim value in the digital key-phone telephone, there is no interference in the transmission / reception signal, and the adjustment of the transmission / reception amount is easy, It is an object of the present invention to provide a sidetone level adjustment device of a digital key phone telephone which improves the quality of a call by preventing sidetone levels caused by the amount of transmission and reception by automatic sidetone level adjustment.

In order to achieve the above object, the present invention provides a digital key phone system comprising a main device and a digital key phone, wherein the digital key phone includes a digital data transmitting and receiving unit for exchanging digital data in a 2B + D channel format with the main device; A control unit for controlling the data transmitter / receiver by analyzing the D-channel data from the main device and controlling the overall operation of the digital key-phone telephone, and converting the B-channel data applied from the digital data transmitter / receiver to an analog signal and handset A signal converter for converting an analog signal from the B-channel data into a signal converter; Amplifier and Transmitter To the output of the side tone level distribution adjusting unit and the sound signal which is fed back to the input of the receiving amplifier it is characterized in that the handset is configured to change to an electrical signal.

Hereinafter, with reference to the accompanying drawings will be described an embodiment of the present invention;

2 is a block diagram of the sidetone level adjusting device of the digital key phone according to the present invention. As shown in the drawing, the main device 30 and the digital key phone 40 are configured, and the digital key phone 40 is a control unit 41. And a digital data transmission / reception 42, a signal converter 43, a sidetone level control section 44, a transmission amplifier 45, a reception amplifier 46, and a handset 47.

The digital data transmitting / receiving unit 42 is connected to the main device 30 to transmit and receive control data and call voice data through the 2B + D channel. The controller 41 analyzes the D-channel data signal applied from the main device 30 through the digital transmitter / receiver 40 to control the digital data transmission / reception 42 and controls the overall operation of the digital key phone. The signal converter 43 converts the received digital channel voice data of the B channel, which is applied from the main device 30 through the digital data transmission / reception unit 42, into an analog signal, and converts the transmission analog signal from the handset 47 into the B channel. Convert to digital call voice data. The transmission amplifier 45 amplifies a user's transmission analog signal from the handset 47 to a predetermined level and applies it to the signal converter 43 side. The receiving amplifier 46 amplifies the received analog signal applied from the signal converter 43 to a predetermined level and applies it to the handset 47 side. The side sound level adjusting unit 44 distributes the transmitted analog signal amplified to a predetermined level through the transmission amplifier 45 and fed back to the input terminal of the reception amplifier 46. The handset 47 converts a signal input to the sound input means into an electrical signal, and converts an electrical signal applied from the receiving amplifier 46 into a sound signal and transmits the sound signal to the sound output means.

At this time, the resistors R1 and R2 for gain adjustment are connected to the output terminal of the signal converter 43, and the outputs of the sidetone level controller 44 and the transmission amplifier 45 are connected to the resistor R2. In addition, the sidetone level control unit 44 can be configured in various ways, but simply connects the resistor (Rx) and the capacitor (Cx) in parallel, and the output signal is a capacitor (connected to the output terminal of the signal converter 43) It is fed back to the receiving amplifier 46 through C3) and resistors R5 and R6. In addition, the transmission amplifier 45 receives the analog signal input from the handset 47 through the resistor R4, partly the inverting terminal (-) input of the first amplifier A1 and partly through the capacitor C2. A capacitor (c1) and a resistor (R3) are connected in parallel between the output point of the first amplifier A1 and the inverting terminal (-) input.

The receiving amplifier 46 has some inputs from the signal converter 43 and the sidetone level control section 44 through the resistor R7, some of which are the inverting (-) inputs of the second amplifier A2, and some of the capacitors. A non-inverting (+) input is made through C4, and the output of the second amplifier A2 is connected to the handset 47. A resistor R8 and a capacitor C7 are connected in parallel between the input terminal and the output terminal of the second amplifier A2.

In the digital key-phone telephone 40 of FIG. 2, the D-channel data of the 2B + D-channel digital data received from the main device 30 by the digital data transmitter / receiver 42 is transmitted to the control unit 41, and the B-channel data is transmitted. Is transmitted to the signal converter 43. The controller 41 analyzes the applied D-channel data and controls the overall operation of data transmission and reception with the host device 30. The B-channel PCM data transmitted to the signal converter 43 is converted into an analog voice signal according to the control signal of the control unit 41, and partly input to the side sound level control unit 44 through the resistor R5 and the capacitor C3. And a part thereof is input to the receiving amplifier 46 through the resistor R7. The analog audio signal received at the input terminal of the receiving amplifier 46 is amplified and transmitted to the handset 47, and a part of it is input to the sidetone level control unit 44. The analog signal is input to the sidetone level control unit 44. The internal circuit is input to the output terminal of the transmission amplifier 45 of the transmission line and the transmission side input terminal of the signal converter 43 with a constant side tone. In the design of the transmission amplifier 45, the output impedance of the transmission amplifier is adjusted to be approximately ø, and transmitted through the main device 30, the digital data transmission / reception section 42, the signal converter 43, and the side sound level adjustment section 44. Since the received signal is almost extinguished at the output terminal of the transmission amplifier 45, there is no signal fed back to the main device 30.

The voice signal transmitted from the handset 47 is amplified by the transmission amplifier 45 and transmitted to the input terminal of the signal converter 43 through the resistors R1 and R2, and part of the signal signal is transmitted through the sidetone level controller 44. Are transmitted to the receiving end output terminal (43) and the input terminal of the receiving amplifier (46). At this time, the impedance Zx of the resistor Rx and the capacitor Cx connected in parallel in the sidetone level controller 44 is {Rx * [1 / (2 * 3.14 * f * Cx)]} / {Rx * [1 * 3.14 * f * Cx)]}, when the output level of the transmitting amplifier 45 is V1, the sidetone level V2 transmitted to the receiving amplifier 46 through the sidetone level adjusting section 44 is V1 * [Zy / (Zx). + Zy)]. Where Zy is the sum of impedances of R5, R6, and C3. The transmission signal transmitted to the input terminal of the receiving amplifier 46 is amplified by the receiving amplifier 46 and fed back to the handset 47. As described above, the feedback signal level, that is, the sidetone level, can be adjusted in the sidetone level control unit 44 through the resistance Rx and the condenser Cx. The transmission voice signal transmitted to the input side of the signal converter 43 through the handset 47 and the transmission amplifier 45 is converted into PCM data by the signal converter 43, and is converted into PCM data by the digital transmitter / receiver 42. Is sent to 30.

In the above-described digital key-phone telephone of FIG. 2, there is no interference between transmission and reception signals during voice signal transmission, and the amount of talks and the sign language are controlled by the transmission signal gain adjustment of the input side of the transmitter of the signal converter 43 and the gain of the reception amplifier 46. It is easy to adjust the volume, and by changing the internal level adjusting element of the sidetone level adjusting section 43, the sidetone level can be adjusted and there is almost no influence on the sidetone by the amount of transmission and reception.

Claims (2)

In a digital key phone system including a main device 30 and a digital key phone telephone 40, the digital key phone telephone 40 transmits and receives digital data for exchanging digital data in a 2B + D channel format with the main device 30. A control unit 41 which controls the data transmitter / receiver 42 by analyzing the receiver 42 and the D-channel data from the main device 30, and controls the overall operation of the digital key-phone telephone, and the digital data transmission / reception. The signal converter 43 converts the B channel data applied from the receiver 42 into an analog signal and converts the analog signal from the handset into the B channel data, and receives and amplifies the analog signal from the signal converter 43. Receiving amplifier 46 for transmitting to 47, and transmitting amplifier 45 for receiving and amplifying the transmission analog voice signal from the handset 47 to the signal converter 43 , The side tone level adjustment device of the digital key phone telephone comprising the side tone level control unit 44 which is fed back to the input of the receive amplifier (46) to distribute an output of said transmission amplifier (45). The side tone level of the digital key-phone telephone according to claim 1, wherein the output impedance of the transmitting amplifier 45 is designed to be close to 'ø' to prevent feedback of the voice signal transmitted from the main apparatus 30. Adjuster.