KR20010000166A - Hand-free device for cellular phone using frequency modulation - Google Patents

Abstract

PURPOSE: A hands-free device of a cellular phone using FM signal is provided to input voice through a microphone and listen outputted voice of the other person through an FM radio, so as to transmit pure tone quality through a wireless transmitting circuit in a PLL(Phase Locked Loop) system, so that broadcasting frequencies of an entire FM broadcasting can be set up and clear speech can be performed. CONSTITUTION: A microcomputer(IC1) controls hands-free receiving voice signal of a cellular phone and re-transmitting the voice signal. An external input circuit having switches is included in the microcomputer(IC1). A PLL(Phase Locked Loop) circuit(180) has a PLL integrated circuit(IC) for transmitting voice signals received from the cellular phone in a PLL system. A transmitting circuit(182) modulates and outputs frequencies with the setup of the PLL circuit(180). A transmitting amplifier circuit(184) amplifies and outputs modulated outputs. A microphone amplifier circuit(122) amplifies outputs of a microphone. A BPF(Band Pass Filter) circuit(124) removes noise in amplified microphone signals. A receiving voice amplifier circuit(130) amplifies received voice of the cellular phone. A speaker amplifier and speaker perform self play for received voice of the cellular phone.

Description

Hand-free device for cellular phone using frequency modulation

The present invention relates to a hand-free, and more particularly, when using a mobile phone while driving a vehicle, the FM signal outputs and listens to the other party's voice through an existing FM tuner mounted on the vehicle and inputs and transmits the user's voice to the mobile phone. It relates to a hand free device of a mobile phone using.

Nearly 10 million vehicles nationwide operate, and frequent mobile phone calls are made while traveling by car. There are a lot of traffic accidents due to the use of mobile phones while the vehicle is in operation, and a law is proposed to prohibit the use of mobile phones while driving. However, the rate of accidents caused by mobile phone calls has been increasing without falling.

The main cause of accidents caused by cell phones while driving is mainly because the driver is holding the steering wheel with only one hand while talking on the phone with one hand. Because you can't.

In order to solve this problem, a hand-free device having a microphone and a speaker can be used to make a call without having to hold the mobile phone by hand.

Hand free kit is a device that mounts a mobile phone on the vehicle's cradle, connects the hand free kit to the connection jack installed on the bottom of the mobile phone, and makes a phone call without using a speaker (or earphone) and a microphone connected thereto. .

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

On the other hand, there has been a proposal to reproduce and output the voice of the mobile phone by using the FM tuner of the vehicle in the past, which is simply by installing the microphone mechanically in the handpiece that generates the voice output of the mobile phone, such as a wireless microphone It picks up and transmits this voice as an RF signal so that it can be received and played by the tuner of the vehicle device.

However, this conventional technology has a big disadvantage that the noise is severe because the RF received by mixing the voice and the ambient noise received through the microphone coupled to the callout.

There is a hand-free device of Patent Application No. 99-51418 as the applicant of the present application that solves the above disadvantages.

According to the above-described application technology, the received voice of the mobile phone is transmitted as an FM signal, and the received and reproduced by the tuner of the vehicle, and the auto scan which finds a frequency for optimal reception is possible.

Although there are several technical advantages, there is a disadvantage of a reception method in which noise is generated during reproduction.

The present invention complements the pre-applied inventions to achieve floating charging using a solar cell, to record and play back call voices, and to allow hand-free reception without increasing the tuner of the car including its own speaker. It is functionally complemented.

The present invention made in order to solve the problems of the prior art as described above has the following object.

According to the present invention, when a user uses a mobile phone, the user can input a voice through a microphone and listen to the voice output of the other party through an FM radio, thereby preventing the traffic accident caused when using the mobile phone. It is to provide a hand free device.

The present invention provides a hand-free device for a mobile phone using an FM signal capable of transmitting and reproducing a clean sound quality through a wireless transmitter of a phase locked communication method (PLL).

The present invention is possible to set the carrier frequency of the entire FM broadcast band, and the free frequency setting of the hand-free according to the conditions of the use area can be changed to a good band at the time of the FM tuner, it is always possible to make a clear call It is to provide a hand free device of a mobile phone using the FM signal.

The present invention is to provide a hand-free device of a mobile phone using the FM signal to be able to store the contents during a call to play the voice when necessary to check the contents of the call.

The present invention is to provide a hand-free device of a mobile phone using the FM signal which is easy to use because the function setting of the hand-free function is recognized through the LCD and when not in use.

The present invention provides a hand-free device for a mobile phone using an FM signal that can be supplied by an automotive power source and a solar cell power source and is easy to supply power.

The present invention, which is made to realize various objects as described above, comprises an external device including a microcomputer as a control center for controlling a hand free for receiving and retransmitting a voice signal of a mobile phone, and a plurality of switches for changing a transmission frequency and controlling a recorder. A PLL circuit section having an input section as the microcomputer input, a PLL IC having a PLL IC for transmitting a voice signal received from a mobile phone in a phase-locked manner, a transmission section for frequency-modulated output by setting the PLL circuit section, and a transmission for amplifying and outputting a modulation output. An amplifier, a microphone amplifier for amplifying a microphone and a microphone output for voice input, a band pass filter for filtering out noise from the amplified microphone signal, a reception voice amplifier for amplifying a received voice of a mobile phone, and the microphone input Level comparison part to compare cell-phone received voice, and howling prevention And a howling prevention unit for limiting speaker amplification to the level comparator signal, and a speaker amplifier and a speaker configured to reproduce a mobile phone received voice by itself. And a LCD display for displaying hand-free control information.

1 is a schematic configuration diagram showing the present invention.

2 is a block diagram showing a configuration of the present invention.

3 is a detailed circuit diagram of the present invention.

4 is a flowchart showing a microcomputer control step of the present invention.

** Description of symbols for the main parts of the drawing **

100: hand-free device 105: control unit 120: microphone

122: microphone amplifier 124: band pass filter 130: reception voice amplifier

132: speaker amplifier circuit 140: external input unit 150: level converting unit

152: level comparison unit 160: howling prevention unit 170: LCD driver

172: LCD display unit 175: audio storage unit 180: PLL circuit unit

182: transmitter 184: transmit amplifier 190: power supply

192: converter 194: constant voltage unit 300: FM tuner

IC1: Microcomputer IC2: PLL IC

Hereinafter, the technical idea of the present invention will be described in detail with reference to the accompanying drawings.

The present invention is connected to the voice output jack of the mobile phone and the other party's voice output is received by the FM transmission and the synchronization is received through the FM radio finished in the vehicle, the voice of the caller is input to the mobile phone through the microphone and transmitted The call is made.

In the process of receiving and playing the voice of the other party, the FM radio may be excluded and the speaker may be reproduced by its own speaker provided in the hand-free of the present invention.

1 shows a schematic configuration of the present invention.

Hand-free device 100 of the present invention is made to be connected to the voice output jack provided in the mobile phone 200, the hands-free device 100 may be driven by a power source of the vehicle or a battery power source using a solar cell.

The hand-free device and the mobile phone are detachable from each other. The hand-free device 100 includes a microcomputer for controlling the transmission of the voice signal between the mobile device and the mobile phone and receives a voice signal received from the outside under the control of the microcomputer. It is provided with a transmitter which transmits again wirelessly by the method.

The FM signal transmitted by the transmitter modulates the voice is wirelessly received through the conventional FM tuner 300 provided in the vehicle, and made to be reproduced as the vehicle speaker 310.

On the other hand, the user's response is picked up by a microphone, amplified and input to a mobile phone, and transmitted through the voice transmission path of a conventional mobile phone to realize a hand-free call.

Looking at the technical configuration of the present invention in more detail as follows.

A block diagram illustrating the configuration of the present invention will be described with reference to FIG. 2 and FIG. 3, which is a detailed circuit diagram.

The present invention is achieved by forming the microcomputer IC1 of the control unit 105 that controls the input / output and external signals of a voice signal and forms a control center of hand-free.

The microcomputer IC1 of the control unit 105 is coupled to an external input unit 140 including a plurality of switches SW1 to SW5, and an LDE for indicating an operation is connected to each switch.

In the switch, SW1 is a recording switch, SW2 is a recording delete switch, SW3 is a recording / playback switch, SW4 is a channel switch for changing the carrier frequency, and SW5 is a power switch.

The microphone amplifier 122 is composed of an amplifier circuit including an OP AMP to amplify the fine voice signal picked up by the microphone 120.

The band pass filter 124 receives the signal of the microphone amplifier 122 and filters out the vibration noise or other noise signal of the vehicle mixed with the signal, and passes only the voice signal. The band of the filter is between 300 Hz and 340 Hz specified by the telephone. Is designed.

The reception voice amplifier 130 includes an OP AMP to amplify the voice signal received from the mobile phone, and includes a filter for filtering out noise generated when the mobile phone is connected to the mobile phone. The loudspeaker amplifiers will then play and listen to their own speakers.

The level converting unit 150 includes an OP AMP and a rectifier circuit for comparing and outputting the voice output passed through the band pass filter 124 and the amplified voice signal passed through the reception voice amplifier 130 with a reference voltage, respectively. D6 and D5) to convert each signal to a DC level. The conversion of the voice signal of the microphone and the mobile phone reception to the DC level is for comparing the voice signal of the mobile phone and the voice signal of the microphone and excludes howling by this comparison, which will be described later.

The level comparator 152 includes an OP AMP for comparing and outputting the output of the level converter 150.

The howling prevention unit 160 is driven at the output level of the level comparison unit 152 and is selectively turned on according to the level, and the mobile phone receiving voice output unit 130 or the microphone amplification is performed through the transistor. The output amplification degree of the unit 122 is made to be limited. The so-called howling, which is output by being fed back to the microphone by increasing the volume of the speaker, is suppressed by reducing the level of the volume generated by the speaker by suppressing the amplification degree to the output of the level comparator.

The amplified signal of the microphone 120 and the voice signal of the received voice amplifier 130 of the mobile phone are respectively connected to the voice storage IC IC3 and connected to be controlled by a microcomputer.

Meanwhile, the microcomputer IC1 connects the LCD driver 170 and the LCD display unit 172 to display the FM transmission frequency, and functions as a clock and displays various malfunctions.

And a PLL circuit unit 180 including a PLL IC (IC2) for carrying a PLL system to control the microcomputer in order to retransmit the received voice signal of the cellular phone as an FM signal. A transmitter 182 for carrying a voice signal is formed and connected, and a modulated amplified FM signal is transmitted through the transmitter 184.

The PLL IC (IC2) acts as a circuit having a very high precision that is not affected by changes in ambient temperature during FM radio frequency transmission.

At the same time, the PLL IC (IC2) is a circuit that provides a carrier frequency of another channel when there is an adjacent FM broadcast that is confused with a retransmitted frequency. Can be done.

The transmitter 182 generates an electric wave by oscillating the FM carrier frequency and modulates the voice of the other party to the electric wave of the FM frequency.

The transmission amplifier 184 performs amplification to transmit the weak FM radio wave oscillated by the transmission unit 182, and the signal part is connected to the above-described PLL IC (IC2) by feedback connection to 4.5 MHz of the PLL IC (IC2). By comparing the difference between the signal oscillated in the oscillator and the carrier frequency of the transmitter 182 is made to correct the deviation in which the difference between the two frequencies.

The correction signal of the PLL IC (IC2) is output to the output pin (DO1) and is converted into a DC voltage through a resistor and a capacitor, causing a change in capacitance (capacitor), thereby changing the oscillation frequency output.

The power supply unit 190 is a circuit for supplying driving power to all circuits. The power supply unit 190 includes a conversion unit 192 including a constant voltage circuit to form a power source using a solar cell, and a battery 196 for charging the output power of the conversion unit. The other power circuit including the power supply circuit of the power supply circuit and the constant voltage unit 194 for directly supplying the vehicle power to the constant voltage power supply is formed in a double.

Looking at the operation of the present invention having the technical spirit as described above in more detail it will be easier to understand the present invention.

According to the present invention, the sound quality of the mobile phone is reproduced by the speaker of the existing vehicle so that the hand-free microphone and the speaker are separated from each other so as not to cause physical interference.

Of course, in addition to cell phone reception voice playback via the car's FM tuner, independent functions are possible with its own hands-free speaker and its own solar cell charging power.

The supply of power required for driving of the present invention is one of two paths of power supply through the constant voltage unit 194 for supplying the vehicle power and the conversion unit 192 for supplying the battery 196 charging power by the solar cell. Power supply via can optionally be achieved.

The hand free device of the present invention connects the voice output jack of the mobile phone to the reception voice amplification unit 130, thereby making a basic preparation for functioning as a hand free by connecting the mobile phone and the hand free.

When the power is applied, the microcomputer IC1 is initialized (S101) and enters a standby state (S102) to function as a free of hands.

When the transmission or reception is started in the standby state, that is, when the call of the mobile phone according to the user's will is started (S103), the microcomputer starts operation (S104).

Selection of a carrier frequency for FM transmission of the voice signal of the other party is performed, and the selected frequency data is applied to the PLL IC (IC2) of the PLL circuit unit 180, and a PLL device is set thereto.

At the same time, the microcomputer IC1 transmits the selected frequency data to the LCD display unit 172 (S106) and the data is displayed on the LCD to confirm the frequency at which the user is currently transmitting.

Here, looking at the call path of the user and the counterpart, the operation process is similar regardless of the incoming call and the outgoing call of the mobile phone.

That is, in the case of an incoming call or a call, after a call is connected by a publicly known operation of a mobile phone, the user's voice is picked up by the microphone 120 of the present invention and connected to the mobile phone through the microphone amplifier 122 to be transmitted. .

The other party's voice is inputted to a voice jack through the received voice amplifier 130 and applied to a transmitter 182 that oscillates at a carrier frequency, and is transmitted as an FM radio wave via the transmission amplifier 184.

When the received voice transmitted by the FM radio is tuned to be received through the normal vehicle radio, the voice of the other party is reproduced by the speaker of the vehicle.

Meanwhile, the received voice may be reproduced by its own speaker through the received voice amplifier 130 and the speaker amplifier circuit 132, and the speaker reproduction is variably adjusted by the volume.

When the call is made and ends as described above, the hand free is controlled to a standby state (S102).

On the other hand, when the intelligibility decreases due to interference with adjacent FM broadcast frequencies during a call, the input of the channel change switch S4 of the external input unit 140 is detected (S112), and if there is a switch input, the channel is changed (S113) and returned. The frequency setting is changed by the microcomputer and the oscillation frequency is changed by the PLL IC, thereby carrying the carrier.

Next, various user settings of the hand free device will be described.

Setting of the user is made by a switch operation of the external input unit 140.

If the external switch input (S110) is detected in the hand-free standby (S102) state, the microcomputer operates (S111).

If the input switch is a channel change switch (S112), the microcomputer sets the FM transmission frequency to the divided nuclear history code (HEXCODE) to set the PERIOD, CLOCK, and DATA to the PLL IC (IC2). It is applied to make a change of the channel (S113). This channel accommodates the entire FM band, and a constant frequency change occurs one step repeatedly at each switch input. This setting prevents interference at the user's position.

At the same time, the changed or set frequency is transmitted to the LCD as channel data (S114) and the LCD displays data input through the LCD driver 170 so as to be recognized by the user.

On the other hand, if there is an input (S116) of the recording switch (S1) during the call, the microcomputer detects whether recording is in progress to record (S118) or terminate recording (S119).

Voice recording of the present invention is preferably made from a semiconductor storage device in terms of durability and management, and may include a tape recorder if necessary.

On the other hand, when the input of the reproduction switch (S3) is detected, the recording contents of the voice storage unit 175 is reproduced (S121), and the reproduction is performed as its own speaker.

If there is no voice input or additional switch input for 20 seconds or more, the microcomputer transmits the clock display data to the LCD (S123) and the LCD switches to the clock display function and returns control.

On the other hand, when the switch input is the delete switch S2, the recording contents are deleted (S126) and control is returned.

According to the present invention as described in detail above, when using a mobile phone, it is possible to input a voice through a microphone and listen to the voice output of the other party through an FM radio, thereby preventing traffic accidents generated when using the mobile phone. It is possible to make a call by transmitting and reproducing clean sound quality through the wireless transmitter of the phase locked communication method (PLL), and the clarity of the call sound is extremely high, and the carrier frequency of the entire FM broadcasting band can be set and used. According to the local conditions, the free frequency setting of the hands-free is varied, so that when the FM tuner crosses, it can be changed to a good band, so that a clear call is always possible, thereby obtaining an optimal call tone.

In addition, the contents can be stored as a voice during a call, so you can check the contents of the call by replaying it when necessary, so that you can escape from the hassle of having to memorize or remember important conversations or necessary information. The function of the hand-free function is recognized through the LCD, and when it is not used, it functions as a clock, which has the effect of transmitting information such as the control status and the current time of the hand-free, and it is possible to supply power by vehicle power and solar power. It is a very excellent invention having various effects that power can be supplied even while the engine is stopped and power supply can be used as a solar cell at ordinary times, and unnecessary wiring can not be taken.

Claims (4)

A hand-free device comprising an external device that amplifies and reproduces a voice output of a mobile phone and picks up and transmits a transmission voice, A microcomputer as a control center for controlling hand-free which receives and retransmits a voice signal of a mobile phone; An external input unit consisting of a plurality of switches to the microcomputer input, A PLL circuit section having a PLL IC for transmitting a voice signal received from a cellular phone in a phase locked manner; A transmitter for frequency modulation and output by setting the PLL circuit, A transmission amplifier for amplifying and outputting the modulated output, A microphone amplifier for amplifying a microphone and a microphone output for voice input; A band pass filter to filter out noise from the amplified microphone signal, A reception voice amplifier for amplifying a received voice of a mobile phone, A hand-free device for a mobile phone using an FM signal, characterized in that it comprises a speaker amplifier and a speaker configured to reproduce the received voice of the mobile phone itself. The apparatus of claim 1, further comprising: a level comparison unit for comparing the microphone input with a mobile phone received voice; Hand-free device of a mobile phone using an FM signal comprising a howling prevention unit for limiting the speaker amplification degree to the level comparison unit signal to prevent howling. The hand free device of claim 1 or 2, further comprising a voice storage unit for storing the voice call signal of the mobile phone and reproducing the call through the microcomputer control. The hand free apparatus of claim 3, further comprising an LCD display for displaying the control information of the hand free.