KR200190068Y1 - Hands free device for cellular phone using fm transmission - Google Patents

Abstract

The present invention relates to a hands-free device of a mobile phone. Specifically, a mobile phone using an FM signal capable of making a call without holding a mobile phone by hand by transmitting and outputting a voice signal of the other party input through the mobile phone on an FM radio frequency. To a hands free device.

The hands-free device of the mobile phone using the FM signal of the present invention, in the hands-free device of the mobile phone, is connected to the terminal of the mobile phone to transmit a voice signal of the caller and to receive the voice signal of the other party from the mobile phone, and An audio amplifier 18 for amplifying a weak audio signal output through the connector 16 into a signal having a sufficient magnitude and removing noise in the audio signal, and a signal output from the audio amplifier 18 at an FM radio frequency. An FM oscillator 20 for synthesis, a first RF amplifier 22 and a second RF amplifier 24 for amplifying a signal modulated by the FM oscillator 20 to a signal level sufficient to be transmitted through an antenna; To amplify the voice signal of the caller input through the microphone 10 and to transmit the microphone amplifier 12 and hands-free operation state to the mobile phone through the connector 16 to display the operation state Includes an LED display 28.

Description

Hands free device for cellular phone using FM transmission

The present invention relates to a hands-free device of a mobile phone. Specifically, a mobile phone using an FM signal capable of making a call without holding a mobile phone by hand by transmitting and outputting a voice signal of the other party input through the mobile phone on an FM radio frequency. To a hands free device.

Mobile phones, cell phones or cellular phones (hereinafter referred to as 'mobile phones') are increasing in popularity so that the majority of people are using them because of the convenience of use, that is, the ability to make calls anywhere.

However, the sequelae of this also occur. A typical problem is traffic accidents caused by traffic accidents while using a mobile phone while driving. In other words, when an emergency occurs while holding a steering wheel with one hand and making a call using a mobile phone with the other hand, the mobile phone must be held in one hand. It is a frequent occurrence.

In order to solve this problem, a hand free device or a hands free device (hereinafter, referred to as a "hands free device") is used. The hands-free device allows the driver to make a call without holding the mobile phone while the mobile phone is mounted. Therefore, the hands free device does not have to hold the steering wheel with only one hand as in the prior art. .

However, the conventional hand-free device has a simple function, such as using a separate microphone and a speaker or earphone instead of simply talking on a mobile phone, when the user inputs a signal to the mobile phone and needs to switch on. Accordingly, there is a need for a hand free device of a mobile phone having more convenient functions and easy to use.

The present invention has been made to solve the above problems, the object of the present invention is to transmit the voice signal of the other party input through the mobile phone to the FM radio frequency to output the phone without holding the mobile phone by hand. The present invention provides a wireless handsfree device for a mobile phone.

Hands-free device of the mobile phone using the FM signal of the present invention for achieving the above object, the connector is connected to the terminal of the mobile phone to transmit the voice signal of the caller and receive the voice signal of the other party from the mobile phone, and the connector An audio amplifier for amplifying a weak voice signal output through the signal to a sufficient size and removing noise in the voice signal, an FM oscillator for synthesizing the signal output from the audio amplifier to an FM radio frequency, and the FM oscillator. A first RF amplifier and a second RF amplifier for amplifying the modulated signal to a signal level sufficient to be transmitted through an antenna, a microphone amplifier for amplifying a voice signal of a caller input through a microphone and delivering the signal to a mobile phone through a connector; Flashes or remains on to visually indicate hands-free operation It includes an LED display.

1 is a block circuit diagram of a hands free device of a mobile phone of the present invention;

2 is an operating state of the hands-free device of the mobile phone of the present invention,

Figure 3 is a detailed circuit diagram of the hands-free device of the mobile phone of the present invention.

<Description of the code | symbol about the principal part of drawing>

10: microphone 12: microphone amplifier

14 echo canceller 16 connector

18: audio amplifier 20: RF oscillator

22: first RF amplifier 24: second RF amplifier

26: voltage regulator 28: LED display

Hereinafter, referring to the accompanying drawings, the hands-free device of the mobile phone using the FM signal of the present invention will be described in detail.

The present invention is to transmit and receive by connecting to a data transmission unit installed in a wireless telephone that can be carried, such as a mobile phone, the other party's voice output is output through the FM radio mounted on the vehicle, the voice signal of the party to the microphone It is a hands-free device that is inputted through a mobile phone to make a call. The data transmission unit included in the mobile phone is used as a separate terminal for transmitting and receiving a signal, for transmitting and receiving a signal using a modem.

1 is a block circuit diagram of a hands-free device of a mobile phone using the FM signal according to the present invention. As shown, the connector 16 is connected to the terminal of the mobile phone to transmit the voice signal of the caller, and receives the voice signal of the other party from the mobile phone, and the weak voice signal output through the connector 16 of sufficient size An audio amplifier 18 for amplifying a signal and removing noise in a voice signal, an FM oscillator 20 for synthesizing a signal output from the audio amplifier 18 to an FM radio frequency, and the FM oscillator 20 Amplifies the first RF amplifier 22 and the second RF amplifier 24 and the voice signal of the caller input through the microphone 10 to amplify the signal modulated by It includes a microphone amplifier 12 for transmitting to the mobile phone through the connector 16, and an LED display unit 28 for displaying the operating state of the hands-free.

The connector 16 is coupled to the data transmission terminal provided in a part of the mobile phone receives the voice signal transmitted from the other party, and also serves to input the voice signal of the caller to the mobile phone. The voice signal input to the cellular phone is wirelessly transmitted through the antenna after being processed by the cellular phone and output through the speaker installed in the cellular phone of the other party.

When the call request signal is input to the cellular phone and the hands-free device is operated, the voice signal of the other party is input through the connector 16, which is output after being amplified by a sufficient size signal by the audio amplifier 18. The signal output from the audio amplifier 18 is input to the FM oscillator 20 to be modulated into a wireless FM signal without being directly output through a speaker. The audio amplifier 18 further includes a filter function that amplifies a weak voice signal and removes noise included in the voice signal, thereby removing noise at the same time as an amplification operation.

The FM oscillator 20 includes a crystal oscillator with excellent precision, and oscillates at the FM radio frequency, and at the same time, the FM oscillation takes place as the oscillation frequency changes according to the change of the audio signal, thereby synthesizing the voice signal to radio waves. Perform.

The signal synthesized and modulated by the FM oscillator 20 is amplified into a signal of sufficient magnitude while passing through the first RF amplifier 22 and the second RF amplifier 24 and then output through the antenna. This signal is a signal in the FM frequency band. When the user of the hands-free device enters the call mode, the user turns on the FM radio installed in the vehicle to output a voice signal input through the mobile phone to make a call.

On the other hand, the voice signal of the caller is input through the microphone 10 and then output as a weak signal. The output signal is amplified into a signal of sufficient magnitude in the microphone amplifier 12 and then input to the mobile phone through the connector 16. The mobile phone processes the input voice signal and wirelessly transmits it through the mobile phone antenna to make a call to the mobile phone.

In the present invention, the echo canceller 14 is further provided to prevent the howling phenomenon from being inputted into the microphone when the volume is increased when the audio signal is output through the speaker of the FM radio. The echo canceller 14 is connected between the output terminal of the microphone amplifier 12 and the output terminal of the audio amplifier 18 to eliminate echo generation.

Reference numeral 26 is a voltage regulator, which is a device for stably supplying power to the hands-free device.

Hands-free device of the present invention is also connected to the LED display unit 28 for displaying the operating state. The LED display unit 28 is operated in accordance with the change of the signal input signal from the mobile phone through the connector.

That is, when a signal is input to the cellular phone and a voice signal from the other party is input to the audio amplifier 18 through the connector 16, it operates by detecting a voltage or current change caused by the generation of the signal. The LED display unit 28 is provided with an LED to visually indicate that the current call is in progress by maintaining a flashing or on state. Although shown in the above description as being connected to the connector 16, it is obvious that it is also possible to configure the sensor to operate by sensing signals at other parts of the circuit.

Figure 3 is an embodiment of a detailed circuit diagram of the hands-free device of the mobile phone using the FM signal of the present invention, showing a state in which the LED display 28 is missing. Brief description of the operating state is as follows. The audio signal input through the connector terminal is amplified by the audio amplifier (circuit including U2A) and then modulated by the FM oscillator (circuit including Q3) to which the crystal oscillator is connected.

The modulated signal is again amplified into a signal of sufficient magnitude in the first RF amplifier (circuit comprising Q1) and the second RF amplifier (circuit comprising Q2) and then transmitted wirelessly through the antenna. The transmitted signal is an FM frequency signal and is output through the speaker after being received from the FM radio provided in the vehicle. The user can listen to the voice of the other party who is output through the FM radio speaker.

On the other hand, the voice of the caller is amplified into a signal of sufficient magnitude in the microphone amplifier (circuit including U3B) after being modulated into an electrical signal through the microphone MIC. The amplified signal is input to the mobile phone again through the connector terminal. The input signal is processed by the cellular phone itself and then transmitted wirelessly through the cellular antenna. The transmitted signal is received by the other party's mobile phone via a base station.

The voltage regulator, which is a device for stably supplying power to the hands-free device, is indicated by U1 in the drawing. In addition, the echo canceller is composed of a circuit including an integrated circuit (U2B) and a transistor (Q4) to prevent the occurrence of howling phenomenon.

According to the present invention as described above it is possible to make a call without holding the mobile phone by hand by transmitting and outputting the voice signal of the other party input through the mobile phone to the FM radio frequency.

Claims (2)

In the hands-free device of a mobile phone, It is connected to the terminal of the mobile phone to transmit the voice signal of the caller and the connector 16 for receiving the voice signal of the other party from the mobile phone, and amplifies the weak voice signal output through the connector 16 to a sufficient size signal The audio amplifier 18 for removing noise in the voice signal, the FM oscillator 20 for synthesizing the signal output from the audio amplifier 18 to the FM radio frequency, and the modulated by the FM oscillator 20 A first RF amplifier 22 and a second RF amplifier 24 for amplifying the signal to a signal level sufficient to be transmitted through the antenna, and a voice signal of a caller input through the microphone 10; The FM signal is characterized in that it comprises a microphone amplifier 12 for transmitting to the mobile phone through, a voltage regulator 26 for power supply, and an LED display unit 28 for displaying the hands-free operation state. Hands-free device of a mobile phone. The method of claim 1, When the volume of the voice signal is output through the speaker of the FM radio, the voice is input to the microphone, and the echo canceller 14 is further included in order to prevent the howling phenomenon from occurring. .