KR930007799B1 - Direct communication method and apparatus of car-phone - Google Patents

Abstract

The cellular phone which is outside the service area but near a transmitter is directly called not via a station using the apparatus and method. The method comprises the steps of: (A) finding that the position is in service area; (B) checking that direct call mode is selected; (C) converting oscillation frequency of a VCO (14,15) and setting high frequency switch according to mode transition control signal; (D) transmitting high frequency signal through receiver high frequency filter (2) and receiving transmitted signal through transmitter high frequency filter; and (E) calling the opponent phone number.

Description

Car phone direct call method and device

1 is a block diagram schematically showing the configuration of a conventional car phone.

2 is a block diagram schematically showing the configuration of a car phone according to the present invention.

3 is a flowchart illustrating a method of directly calling a car according to the present invention.

* Explanation of symbols for main parts of the drawings

1: transmitting and receiving antenna 2, 12: high frequency filter

3, 11: high frequency amplifier 4: mixer

6: demodulator 7: central processing unit (microcomputer)

8: handset 9: frequency synthesizer

13: high frequency switch 5, 14: receiving voltage controlled oscillator

10, 15: transmit voltage controlled oscillator

The present invention relates to a cellular phone (hereinafter, simply referred to as a "car phone"), particularly in a service area or in a hearing loss area, without having to call a counterpart's phone number directly between a near-terminal vehicle telephone to make a call. The present invention relates to a direct call method of a car and a device thereof.

The conventional car phone was configured as shown in FIG. 1, which will be described in brief.

First, in order to receive, the 870MHz-890MHz received signal input through the antenna (1) is filtered by the high frequency filter (2), and then amplified by the high frequency amplifier (3) and input to the mixer (4). . In the mixer 4, the 915-935 MHz signal generated by the reception voltage controlled oscillator 5 and the 870 MHz-890 MHz amplified by the high frequency amplifier 3 are mixed to apply a 45 MHz signal to the voice and data demodulator 6. . Then, the voice and data demodulator 6 mixes and demodulates the input 45 MHz signal to the central processing unit 7 (hereinafter, simply referred to as "microcomputer"). Each information for operating the handset 8 is read and analyzed and then executed.

On the other hand, in the case of transmission, the central processing unit 7 provides transmission information to the transmission / reception frequency synthesizer 9 according to the operation of the handset 8, and causes the synthesizer 9 to synthesize high frequency data. do.

At this time, the frequency synthesizer 9 provides a signal to the transmit voltage controlled oscillator 10. The transmit voltage controlled oscillator 10 generates a transmit frequency of 825-845 MHz and provides the signal to the transmitting high frequency amplifier 11. .

Then, the high frequency amplifier 11 for transmission amplifies and transmits the input frequency signal under the control of the microcomputer 7 to the high frequency filter 12.

The high frequency filter 12 outputs the transmission frequency signal to the outside through the antenna 1 in the 825-845MHz bandwidth.

However, such a conventional car phone is given a service area, and all car phones can be used only in the service area regardless of the distance between the car phones, and the communication method can always communicate with each other only through a control station. In other words, even if a little out of the service area was not able to make a call, even if the car phone to be located in the adjacent location was a very inconvenient problem that can not communicate.

Accordingly, the present invention has been made in view of the above circumstances, and the car phone can be used to directly make a call between car phones without passing through a control station within a distance within which the car output can be reached outside the service area or in the hearing loss area. An object is to provide a call device and a device.

In order to achieve the above object, the present invention uses a car phone configured to receive a first band frequency signal transmitted from a control station at the time of reception, and to transmit a second band frequency signal to the control station at the time of transmission, outside the service area. In the method of directly speaking with the other party's car phone without arbitration of the control station, the first step of determining whether the current location is within a callable service area, and in order to confirm whether a direct call mode is selected when outside the service area, The second step of judging whether or not the key is input, the variable song to allow direct call with the other car phone. By switching the oscillation frequency of the receiving voltage controlled oscillator and the connection state of the high frequency switch through the mode switching control signal, the frequency transmitted through the antenna is the same as the frequency of the first band, but is output through the high frequency filter on the receiving side. A third step of receiving the received second band frequency signal through the high frequency filter of the transmitting side to the high frequency amplifier of the receiving side; And a fourth call method of the car phone, which is performed by calling the other party's car phone to be called, and a first high frequency signal for receiving and filtering the first band frequency signal from the control station through the antenna. Filtering means, second high frequency filtering means for transmitting the second band frequency signal transmitted through the antenna, first high frequency amplifying means for amplifying the received signal, and second high frequency amplification for amplifying the transmission signal. Means, mixing means for mixing the received signal output from the first high frequency amplifying means and a predetermined oscillation output signal, demodulation means connected to the output terminal of the mixing to demodulate voice and data, and the demodulation means and the first means. 2 Control means for controlling the overall operation connected to the high frequency amplification means and the handset for various key operation An apparatus for directly talking to a counterpart car phone without intervention of the control station by using the provided car phone, wherein the direct call with the other party outside the service area is different from the case where it is in the service area under the control of the control means. Variable transmission frequency oscillating means for generating a frequency signal equal to one band frequency and outputting the same to the second high frequency amplifying means; A variable reception frequency oscillating means for generating a frequency signal having a frequency band difference of a predetermined magnitude with the second band frequency signal according to the control of the control means, and outputting the mixed signal to the mixing means: and mode conversion control from the control means Operating in accordance with the signal to cause the output signal of the second high frequency amplifying means for transmission to be transmitted to the outside through the first high frequency filter for reception, and to transmit the high frequency signal received through the antenna to the second high frequency signal for transmission. Provided is a car phone direct call apparatus including switching means for connecting from a filter to the first high frequency amplification means for reception.

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

2 is a block diagram of a car phone for a direct call according to the present invention, in which reference numerals identical to those of FIG. 1 denote the same parts, where 1 is a transmitting and receiving antenna, and 2 and 12 are high frequency. Filter, 3 and 11 are high frequency amplifiers, 4 are mixers, 6 are demodulators, 7 are microprocessors, 8 are handsets, 9 are frequency synthesizers, 13 are high frequency switches, 5 and 14 receive voltage controlled oscillators, 10 And 15 show transmission voltage controlled oscillators, respectively.

The car phone shown in FIG. 2 can communicate with the other party only through a control station (not shown) in the service area, and can communicate directly with the other party without passing through the control station outside the service area.

First, the 870 MHz-890 MHz signal received through the antenna 1 under control by the control station (i.e. in a service area) is filtered by the receiving high frequency filter 2 and then input to the high frequency switch 13. In this case, the high frequency switch 13 is connected to a specific control signal line (a) of the microcomputer (7) and operates according to the control signal output therefrom to output the output signal from the high frequency filter (2) to a high frequency amplifier (3). ) Is applied.

Then, the high frequency amplifier 3 amplifies and outputs the input signal, and the mixer 4 uses the 915-935 MHz signal b and the high frequency amplifier 3 output from the receiving voltage controlled oscillator 14 as in the conventional case. The 45MHz signal is generated by mixing the output signal of the signal and applied to the secondary mixer and demodulator 6 at the rear stage.

Thus, the signal demodulated by the secondary mixing and demodulator 6 is applied to the microcomputer 7, and the microcomputer 7 reads and analyzes each piece of information and then executes it to be provided to the handset 8.

On the other hand, in the case of transmission, the signal input from the handset 8 is recognized by the microcomputer 7 to provide the channel data information to the transmission / reception frequency synthesizer 9. Thus, the high frequency data is synthesized by the frequency synthesizer 9 and the transmission voltage controlled oscillator 15 so that a predetermined transmission frequency is applied to the high frequency amplifier 11. The high frequency amplifier 11 receives and amplifies the transmission information from the microcomputer 7 and applies the amplified signal to the high frequency switch 13.

At this time, the high frequency switch 13 provides a signal applied to the receiving high frequency filter 12 under the control of the microcomputer 7 to transmit a frequency signal of 825 MHz to 845 MHz through the antenna 1.

In a preferred embodiment of the present invention, the microcomputer 7 is configured using an 8-bit CPU, a ROM, a RAM, and a microcomputer having a plurality of input / output ports. RSSI) is easily detectable via an 8-bit A / D converter and handles the overall functions of reading keystrokes and analyzing the transmission and reception with the control station.

Now, the process of the present invention will be described in detail with reference to the performance flowchart of FIG. 3.

As shown in FIG. 3, the microcomputer 7 checks each state of the car phone main program to form a loop (101), and determines whether the current car phone is located in the service area ( 102) If it is in the service area, the car proceeds to the first time and the car phone continuously monitors the current position.

However, when the location of the car is out of the service area, when the user wishes to communicate directly with the other party's car (103), the user is supposed to press a specific function key of the handset. When a signal obtained by the operation is applied to the microcomputer 7, the microcomputer 7 generates a mode switching control signal to the control signal line a and applies channel data to the frequency synthesizer 9.

At this time, the receiving voltage controlled oscillator 14 oscillates 870 MHz to 890 MHz, which is 45 MHz lower than that in the service area (915-935 MHz), and the transmitting voltage controlled oscillator 15 is increased by 45 MHz than the case in the service area. Oscillate the frequency of 870MHz-890MHz.

The 870 MHz to 890 MHz signal generated by the transmitting voltage controlled oscillator 15 is transmitted to the high frequency switch 13 through the receiving high frequency amplifier 11, and the high frequency switch 13 is controlled by the microcomputer 7. It operates to connect the signal applied from the high frequency switch to the receiving high frequency filter (2).

Therefore, the high frequency filter 2 acts as a transmission filter, so that the 870MHz-890MHz signal is transmitted to the other party's car through the antenna 1 (104).

At this time, the user presses a Send button after inputting a telephone number as in general telephone dialing, and when the operation is performed (105), when the operation is performed, the other party's call data is the same as that through the control station. Is transmitted via 106. In this data transmission, since the response data is not received if the other party is in the service area or outside the coverage area, the microcomputer 7 first determines whether there is a response signal of the other party (107), and if there is no response, the agreed tone (Tone) And generate a notification to the user (108).

If there is a response signal (107), it detects the channel not used in the voice channel (109), and transmits the unused channel information to the other party through the control channel (110), the voice channel according to the response signal of the other party It is transmitted (111).

Here, when a response signal is received from the other party through the antenna 1, the frequency signal of 825MHz-845MHz band transmitted from the other party is applied to the high frequency switch 13 via the receiving high frequency filter 12. do. At this time, since the high frequency switch 13 is switched to output an input applied to the receiving high frequency amplifier 3 by the control of the microcomputer 7, the signal passing through the high frequency filter 12 is a high frequency switch 13. It is amplified by the receiving high frequency amplifier 3 via and then applied to the mixer 4.

The mixer 4 generates a 45 MHz frequency by mixing the oscillation signal of the received voltage controlled oscillator switched from 870 MHz to 890 MHz and the output signal from the high frequency amplifier 3 to generate normal reception as described above.

The present invention operating in this way is that the known high frequency filter itself has no directivity, and when impedance matching is achieved, the high frequency frequency level is transmitted in both directions without loss. It is possible to communicate with each other within the range of the call, and to eliminate crosstalk during the call and to avoid passing through the control station, thereby simplifying the call and reducing noise.

Claims (2)

Receiving the first band frequency signal transmitted from the control station at the time of reception, and using the car phone configured to transmit the second band frequency signal to the control station at the time of transmission, it is possible to communicate with the other car phone without intervention of the control station outside the service area. A direct call method, comprising: a first step of determining whether a current location is within a callable service area; A second step of determining whether a specific key has been input in order to confirm whether a direct call mode is selected when the service area is outside the service area; The oscillation frequency of the variable transmit / receive voltage controlled oscillators 14 and 15 and the connection state of the high frequency switch 13 can be switched through a mode switching control signal so as to be able to directly talk to the other car phone, and transmitted through the antenna 1. The frequency is the same as the frequency of the first band, but is output through the high frequency filter (2) of the receiving side, and the received second band frequency signal through the high frequency filter (12) of the transmitting side 3) third step to be applied; And a fourth step of calling the other party's car phone to be talked with each other. Reception first high frequency filtering means 2 for receiving and filtering the first band frequency signal from the control station via the antenna 1, and transmission first filtering the second band frequency signal transmitted through the antenna. A second high frequency filtering means 12, a first high frequency amplifying means 3 for amplifying a received signal, a second high frequency amplifying means 11 for amplifying a transmission signal, and the first high frequency amplifying means 3 A mixing means (4) for mixing the received signal outputted from the predetermined oscillation output signal, a demodulation means (6) connected to an output terminal of the mixing means (4) to demodulate voice and data, and the demodulation means ( 6) and the other party without intervention of the control station using a car phone connected to the second high frequency amplifying means 11 and the handset 8 for various key operations and having a control means 7 for controlling the overall operation. Talk directly with your car In one apparatus, the second high frequency amplifying means generates a frequency equal to the first band frequency for direct communication with a counterpart outside the service area, unlike in the service area under the control of the control means 7. Variable transmission frequency oscillating means (9, 15) for outputting the signal; Variable reception frequency oscillation means 9 and 14 for generating a frequency signal having a frequency band difference of a predetermined magnitude from the second band frequency signal under the control of the control means 7 and outputting the frequency signal to the mixing means 4. ; And an output signal of the second high frequency amplification means 11 for transmission to the outside through the first high frequency filter 2 for reception by operating in accordance with a mode conversion control signal from the control means 7. Switching means (13) for transmitting a high frequency signal received through the antenna (1) so as to be applied from the second high frequency filter (12) for transmission to the first high frequency amplification means (3) for reception. Car phone direct call apparatus comprising a.

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