JPH0828909B2 - Direct call method and device for automobile telephone - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a cellular phone (hereinafter, referred to as a car phone), particularly in a service area or a hearing-impaired area. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a direct call method for an automobile telephone and an apparatus for calling a telephone number of another party between telephones of a vehicle (for example, an automobile) at a distance without passing through a control station.

(Prior Art) The configuration of a conventional automobile telephone is as shown in FIG. 1, which will be described briefly.

First, when receiving, the received signal of 870 to 890 MHz input through the antenna 1 is filtered by the high frequency filter 2, amplified by the high frequency amplifier 3, and input to the mixer 4. Mixer 4
Mixes the 915 to 935 MHz signal generated by the reception voltage controlled oscillator 5 with the 870 to 890 MHz signal amplified by the high frequency amplifier 3, and the 45 MHz signal thus obtained is applied to the audio data demodulator 6. The voice data demodulator 6 has been input
Central processing unit 7
Then, the central processing unit 7 interprets and analyzes each information for operating the handset 8 and then executes the processing.

On the other hand, when transmitting, the central processing unit 7 provides transmission information to the frequency synthesizer 9 for transmission / reception under the control of the handset 8. Then, the frequency synthesizer 9 synthesizes the high frequency data.

When the frequency synthesizer 9 provides a signal to the transmission voltage controlled oscillator 10 in this way, the transmission voltage controlled oscillator 10 is 825 to 845 MHz.
The transmission frequency of z is generated and sent to the transmission output amplifier 11.

The transmission output amplifier 11 amplifies the input transmission frequency signal and applies it to the high frequency filter 12 under the control of the central processing unit 7.

The high frequency filter 12 is 825 to 845 MH through the antenna 1.
The transmission frequency signal is output to the outside within the frequency bandwidth of z.

However, since such a conventional car phone has a limited service area, all car phones can be used only within the service area regardless of the distance between the car phones. Calls to each other were possible only via the control station. That is, since it is not possible to make a call even if it is slightly out of the service area, there is a problem in that a call cannot be made even if the car telephone of the other party is trying to make a call.

(Object of the Invention) The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a vehicle for an automobile without going through a control station within a range where the output of the automobile telephone can reach outside a service area or a hearing-impaired area. It is an object of the present invention to provide a direct call method for an automobile telephone and an apparatus therefor, which enables direct calls between telephones.

(Structure of the Invention) According to the present invention, in the direct communication method for the automobile telephone, which receives the first band frequency signal transmitted from the control station at the time of reception, and transmits the second band frequency signal to the control station at the time of transmission, Furthermore, if it is judged whether it is within the service area where the call is possible, and if it is judged that it is outside the service area and trying to make a direct call with the other party without going through the control station, the control station during transmission. A signal of the same frequency as the first band frequency transmitted from the antenna is generated and transmitted through the antenna,
Further, there is provided a direct call method for an automobile telephone, which is characterized in that at the time of reception, the frequency of the signal received through the antenna is made the same as the second band frequency transmitted to the control station to generate the signal of that frequency. .

Further, according to the present invention, a high-frequency filter for reception which receives the first band frequency signal sent from the control station through the antenna and filters it, and filters the second band frequency signal which is transmitted to the control station through the antenna. In the case of a direct communication device for an automobile telephone equipped with a transmitting high frequency filter and a control means for controlling the high frequency filter, etc., when trying to directly communicate with the other party outside the service area without going through the control station, Transmission frequency varying means for generating a signal transmitted through an antenna by making its frequency the same as the frequency of the first band frequency signal transmitted from the control station, let's talk directly to the other party without going through the control station outside the service area , The second band frequency for transmitting the frequency of the signal received through the antenna to the control station during reception. Receiving frequency variable means that is generated at the same frequency as the signal, and operates at the time of transmission in response to the first control signal generated by the control means, and outputs the output frequency signal of the transmitting frequency varying means to the outside through the high frequency receiving filter. And a switch means for operating in response to the second control signal generated from the control means at the time of reception to receive the frequency signal received from the antenna through the transmission high-frequency filter. A direct call device is provided.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 2 is a block diagram showing the construction of an automobile telephone for direct communication according to the present invention, in which the same reference numerals as those in FIG. 1 designate the same parts.

The car telephone shown in FIG. 2 can talk with the car telephone of the other party only through the control station (not shown) in the service area, and does not go through the control station outside the service area. Can also make direct calls with the other party.

Under control of the control station (ie, within the service area)
The 870 to 890 MHz signal input through the antenna 1 is filtered by the high frequency receiving filter 2 and then input to the switch 13. At this time, the switch 13 operates by the control signal a generated from the central processing unit 7 configured by a microcomputer or the like, and applies the output signal of the high frequency filter 2 to the high frequency amplifier 3. The high frequency amplifier 3 amplifies the input signal and outputs it to the mixer 4. The mixer 4 mixes the signal b output from the receiving voltage controlled oscillator 14 with the output signal of the amplifier 3 to generate a 45 MHz signal, which is applied to the audio data demodulator 6 which performs secondary mixing and demodulation. The signal demodulated through the voice data demodulator 6 is applied to the central processing unit 7, which will read and analyze each information and then perform the processing to provide the information to the handset 8.

On the other hand, in the case of transmission, the signal sent from the handset 8 is recognized by the central processing unit 7, and the central processing unit 7 provides the information to the transmitting / receiving frequency synthesizer 9. At this time, the high frequency data is sent to the transmission output amplifier 11 via the frequency synthesizer 9 and the transmission voltage controlled oscillator 15.
Then, the transmission output amplifier 11 operates by receiving the information from the central processing unit 7, and the signal amplified as a result is switched by the switch 13
Is applied to At this time, the switch 13 provides a signal to the transmission high-frequency filter 12 under the control of the control signal a of the central processing unit 7 generated at the time of transmission, and thereafter the signal of the frequency of 825 to 845 MHz is transmitted through the antenna 1. It has become. The switch 13 can be composed of an RF relay, a pin diode, or the like.

Next, the operation of the direct call according to the present invention will be described with reference to the flowchart of FIG.

First, the central processing unit 7 checks each state of the main program of the automobile telephone to form a loop (step 101), and judges whether the current position of the automobile telephone is within the service area (step). 102), if it is within the service area, the program is returned from step 102 to step 101 to continuously monitor the current state of the automobile telephone.

On the other hand, if the position of the automobile telephone is outside the service area, the program proceeds to step 103. here,
When the user of the car telephone wants to communicate directly with the other car telephone (step 103), the user operates the handset 8 to transmit a signal indicating that the handset 8 is directly transmitted to the central processing unit 7, and Thereby, the central processing unit 7 generates the control signal a and applies the channel data to the frequency synthesizer 9.

At this time, the voltage control oscillator for reception 14 oscillates a frequency of 870 MHz, which is 45 MHz lower than that in the case of FIG. 1, and conversely the frequency of the voltage control oscillator for transmission 15 is increased by 45 MHz as compared with the case of FIG. It is 890MHz. The signal of 870 to 890 MHz generated from the transmission voltage controlled oscillator 15 is sent to the switch 13 operated by the control signal a from the central processing unit 7 via the transmission output amplifier 11 and then connected to the transmission high frequency filter 12. It

Therefore, the high frequency filter 12 plays a role of a transmission filter, so that 870 to 890 MHz is transmitted through the antenna 1.
Is sent to the other party's automobile telephone (step 104). At this time, the user presses the send button after inputting the telephone number (step 105), as in the case of general telephone dialing, and if this works, it is done via the control station. Similar to the case, the call data of the other party is transmitted through the antenna 1 (step 106). When such a transmission is performed, the response data does not come if the other party is within the service area or out of the service area, so the central processing unit 7 first determines whether or not there is a response signal from the other party (step 107) If there is no response, a predetermined tone is generated to inform the user of that (step 108).

On the other hand, in step 107, if there is a response signal, an unused channel in the voice channels is detected (step 109), information of the unused channel is transmitted through the control channel (step 110), and the other party The signal is transmitted to the voice channel according to the response signal (step 111).

Here, when the response signal from the other party is received through the antenna 1, 825 to 845 MH transmitted from the other party.
The z-band frequency signal is applied to the switch 13 via the transmission high-frequency filter 12. At this time, since the switch 13 is connected to the high frequency amplifier 3 under the control of the central processing unit 7 in the reception mode, the high frequency filter 12
The signal that has passed through the
Is input to the mixer 4, amplified by the high frequency amplifier 3, and then applied to the mixer 4. The mixer 4 mixes with the signal converted to 870 to 890 MHz to generate a frequency of 45 MHz, which means that the normal reception is performed as described above.

(Effects) According to the above-described direct call method and apparatus thereof according to the present invention, the car telephone which has been conventionally unusable outside the service area or the hearing-impaired area allows 3 watts (WATT) even in the conventionally unusable area. ) Can communicate with each other within the communication distance.

Further, according to the method of the present invention, since communication is possible without going through a control station, there are no problems caused by crosstalk, and there is an advantage that noise is reduced because the communication path is simple. ing.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a conventional automobile telephone, FIG. 2 is a block diagram showing a configuration of an automobile telephone according to the present invention, and FIG. 3 is a control diagram for direct call according to the present invention. It is a flowchart. <Description of symbols of main parts> 1 ... Transmitting / receiving antennas 2, 12 ... High frequency filter 3, 11 ... High frequency amplifier 4 ... Mixer 7 ... Central processing unit 8 ... Handset 9 ... Frequency synthesizer 13 …… High frequency switch 14 …… Receive voltage controlled oscillator 15 …… Transmit voltage controlled oscillator

Claims (2)

[Claims] 1. A direct call method for an automobile telephone which receives a first band frequency signal transmitted from a control station at the time of reception and transmits a second band frequency signal to the control station at the time of transmission, and further communication is possible. When it is judged whether it is in the service area, and when it is judged that it is outside the service area and trying to make a direct call with the other party without going through the control station, the data is transmitted through the antenna when directly transmitting to the other party. Generated signal with the same frequency as the frequency of the first band frequency signal transmitted from the control station, and when directly receiving from the other party, the frequency of the signal received through the antenna is transmitted to the control station. A direct communication method for an automobile telephone, which is generated in the same manner as the second band frequency signal to be transmitted. 2. A high frequency receiving filter for receiving a first band frequency signal transmitted from a control station through an antenna and filtering the same, and a second band frequency signal transmitted to the control station through the antenna. In a direct communication device for an automobile telephone equipped with a transmission high-frequency filter and a control means for controlling the high-frequency filter, etc., when a direct call is made with the other party outside the service area without going through the control station, the transmission is performed. Occasionally, a transmission frequency varying means for generating a signal transmitted through the antenna with the same frequency as the frequency of the first band frequency signal transmitted from the control station, the other party outside the service area without passing through the control station. When making a direct call with the Reception frequency varying means for generating the same frequency as the frequency of the second band frequency signal transmitted to the control station, and output frequency of the transmitting frequency varying means operated by the first control signal generated by the control means during transmission. A switch means is further provided for transmitting a signal to the outside through the high frequency filter for reception, and when receiving, operating by a second control signal generated by the control means to receive a signal received from the antenna through the high frequency filter for transmission. A direct communication device for an automobile telephone, which is characterized by being provided.