JP2699617B2 - Cellular telephone responding to serviceability for operation in different cellular telephone systems - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates generally to wireless telephones and, more particularly, to an improved cellular telephone that operates on two different cellular telephone systems.

BACKGROUND OF THE INVENTION Today's cellular telephones are designed to work with only one cellular telephone system. In most countries of the world, only one cellular telephone system is implemented. Thus, for the cellular system of most countries in the world,
A cellular telephone that operates with only one cellular telephone system was sufficient. However, in some countries, cellular systems have replaced and / or supplemented older systems that are not cellular radiotelephones. For example, in the United States, cellular systems have been providing improved cellular telephone services since the late 1960s.
MTS) and / or complement the old system. Prior art wireless telephones are used in both IMTS and cellular systems, and
It had both a TS transceiver and a cellular transceiver, which were connected to a common handset controller. In this prior art wireless telephone, the voice signal was switched from either the IMTS transceiver or the cellular transceiver to a common handset controller by the user's selection. Providing a service using two different types of wireless telephone systems using two transceivers increases the bulk and becomes relatively expensive. Another type of signal switching found in prior art instruments is the modulation analyzer.
The bandwidth of the intermediate frequency (IF) stage of the radio receiver is mechanically switched. The IF stage of such a meter is switched between two different bandwidths by a diode switching circuit by the user activating a mechanical switch. However, the method of mechanically switching the IF bandwidth with such instruments is not suitable for use in cellular telephones and requires user intervention and additional circuitry, increasing cost and complexity. For the reasons mentioned above,
There is a need for a cellular telephone that accepts different receiver bandwidths operating in different cellular telephone systems.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an intermediate frequency stage for a cellular telephone receiver so as to automatically operate in different cellular telephone systems using service availability and radio signal availability as switching criteria. To provide a unique dual system cellular telephone having a bandwidth switching mechanism and a software switching mechanism in the controller.

(Embodiment) Referring to FIGS. 1, 2 and 3, a transceiver 10 of a dual system cellular telephone embodying the present invention will be described.
0, voice / logic control device 200 and handset device 3
00 are respectively shown. The cellular telephone of the present invention
It can be used effectively in all countries or service areas where different types of cellular telephone systems exist. For example, a TACS-type cellular telephone system and a US-type cellular telephone system provide at least partially overlapping cellular telephone services for the same geographic area. Today, two different types of cellular telephone systems are licensed in Japan and Hong Kong. In urban areas or highways where only one of the two types of cellular telephone systems provides cellular service, the cellular telephone of the present invention automatically switches to the serving cellular system and is always available to the user. Ensure access to cellular services where possible. Where appropriate, two different typical cellular telephone systems are referred to below as cellular telephone systems.
Called system A and cellular system B.

Next, referring to the block diagram of FIG.
Preferably, the cellular transceiver has a transmission frequency range of 915 MHz to 940 MHz and a reception frequency range of 850 MHz to 885 MHz. Except for block 150, each block of transceiver 100 is implemented by a conventional cellular transceiver circuit, such as a US-type cellular telephone transceiver, which is a Motorola operating manual titled "DYNATAC Cellular Mobile Phone". Illustrated and described in No. 68P81070E40, published and sold by Motorola C & E Parts, Inc., 1313 East Argonquin Street, Schaumburg, Illinois, 60196.

The RF signal of the cellular radio channel is transmitted and received by the transceiver 100 via the antenna 120 and the harmonic filter 122. The RF signal transmitted by the antenna 120 is applied to the harmonic filter 122 by the transmission duplex filter 126 via the duplex transmission line 124. The transmission circuit of the transceiver 100 includes an offset voltage controlled oscillator (VCO) 108, an offset mixer 110, a power amplifier 112, and a directional coupler 114. The transmission circuit transmits an RF signal to be tuned by the transceiver 100. Oscillates. Synthesizer 104 is connected to reference oscillator 102 to generate a receiver injection signal, which is split by splitter 106 into offset mixer 110 and injection filter 1.
Connected to 16. Synthesizer 104 provides data signals 907,
The audio logic controller 200 tunes to a particular radio channel using the clock signal 906 and the RX enable signal 905. The offset VCO 108 is connected to a reference oscillator 102 to generate an offset signal, which is mixed with a receiver injection signal at an offset mixer 110 to generate a transmission signal. Offset VCO1
The circuit 08 powers up and down in response to the TX pre-key signal to conserve current flow during standby. Amplifier 112 generates up to eight different levels of power at its output in response to PA control signal 902 from voice / logic controller 200. The directional coupler 114 generates an RF detection signal 901, the magnitude of which is proportional to the magnitude of the output of the amplifier 112. RF detection signal 9 from directional coupler 114
01 is connected to an audio logic controller 200, where this signal is converted to a digital signal and the PA control signal 902 is maintained to maintain the output of the amplifier 112 at the desired power level.
Used to generate

In the reception path of the transceiver 100, the reception signal is transmitted from the harmonic filter 122 to the reception duplex filter 130, the RF amplifier 132, the receiver filter 134 and the transmission line 1 through the double transmission line 128.
The received signal, which is coupled to the first mixer 138 by 36, is filtered by the injection filter 116 and the transmission line 1
Mixed with the receiver injection signal from 18
Generate the F signal. The first IF signal from the first mixer 138 is
Coupled to crystal filter 140, IF amplifier 142 and crystal filter 144, selects the desired component of the IF signal. The output of the crystal filter 144 is coupled to a second mixer 148, where it is mixed with a second local oscillator 146 to generate a second IF signal.
The second IF signal from the second mixer 148 is supplied to the switching IF filter 15
Coupled to zero, this filter has first and second filters of different bandwidths to select the desired components of this signal for cellular system A and cellular system B, respectively. In the preferred embodiment, the first filter of the switched IF filter 150 has a wide bandwidth, ie, +12 KHz.
And the second filter of the switching IF filter 150 has a narrow bandwidth, i.e., a 3 dB bandwidth of ± 6 KHz. When implementing the present invention, the switching IF filter 15
0 may have another filter to select the desired signal component for another cellular system besides cellular system A and cellular system B. The bandwidth control signal 908 from the audio / logic controller 200 is connected to a switching IF filter 150, which switches between a first filter and a second filter of this filter 150. When the bandwidth control signal 908 is 2
In the case of a radix one state, the first filter of the switching IF filter 150 is selected, giving a wide bandwidth for the cellular system A. When the band control signal 908 is a binary 0 state, the second filter of the switching IF filter 150 is selected, providing a narrow bandwidth for cellular system B. The output of the switching IF filter 150 is coupled to a detector 152, which generates a discriminator audio signal 909 and a signal (RSSI) 910 indicating the strength of the received signal, which signals are audio / logic signals. Coupled to control device 200.

Next, referring to the block diagram of FIG. 2, the audio / logic control device 200 has a microcomputer 202, which controls the operation of the transceiver 100 according to a control program stored in an EPROM memory 204, The first part, which performs signal processing and call processing of the cellular system A,
A second part for performing signal processing and call processing of system B, and a user system for cellular system A and cellular system B;
It has a third part that interfaces. In the preferred embodiment, microcomputer 202 is Motorola 68H
This is a C11 type microprocessor integrated circuit. Microcomputer 202 is also coupled to EEPROM memory 206 for accessing telephone numbers, serial numbers, and other call processing information stored in this memory. In the preferred embodiment, the dual system cellular telephone of the present invention has two types of telephone numbers, one for cellular system A and one for cellular system B. Microcomputer 202 is coupled to audio circuit 210 to control the transmit and receive audio paths, and to the microphone signals 911 and RX HI signals for operation in both cellular system A and cellular system B, respectively. You. Audio circuit 210 is described in further detail in U.S. Pat. No. 4,741,018. When operating in cellular system A, microcomputer 202 is coupled to signaling circuit 208 to provide high speed signaling data (FWD D) used for call processing.
ATA and REV DATA), audible sound for management (FWD SAT and REV SA)
T) and two tone multi-frequency dial signal (LOW DTMF and
HIGH DTMF). Signaling circuit 208 is described in further detail in U.S. Patent Nos. 4,302,845 and 4,312,074. When operating in cellular system B, the reduced rate signal data in discriminator audio signal 909 from transceiver 100 is coupled to microcomputer 202 by receiver filter 212 and limiter 214. The reduced rate data from microcomputer 202 for transmission in cellular system B is coupled to modulated signal 904 by transmitter filter 216 and applied to offset VCO 108 of transceiver 100. The DC control circuit 218 responds to an ON / OFF signal from the handset device 300 and an ignition detection signal 917 from an automatic ignition switch, and generates a reset signal for initializing the microcomputer 202, the signal generation circuit 208, and the audio circuit 210. A power supply that is generated and switched to 5V and 9.5V is generated to supply power to the circuit of the transceiver 100, the voice / logic control circuit 200, and the handset signal 300. DC control circuit 218 has a conventional constant voltage source, which is described in further detail in U.S. Patent No. 4,798,975.

Referring now to FIG. 3, handset 300 scans keypad 306 to detect actuated keys, and display 304 for displaying the telephone number and predetermined status of the dual mode cellular telephone of the present invention. Has a microcomputer 302 for giving information to the user. Handset 300 also has a microphone 310 and a speaker 314, which are coupled to microphone signal 911 and RX HI signal 912 by amplifiers 308, 312, respectively, which can be switched on and off by microcomputer 302. Handset device 300 also has several indicators, one of which
One is a denial of service indication that visually indicates whether a cellular service is available. The microcomputer 302 generates an ON / OFF signal 916 in response to the operation of the ON / OFF key of the keypad 306. Microcomputer 302
Communicates via a three-wire data bus 913,914,915 with the microcomputer 202 of the audio / logic controller 200, which is shown and described in U.S. Pat. No. 4,369,516. The TRU signal 913, CMP signal 914, and RTN signal 915 on the three-wire data bus are coupled to amplifiers 316, 317, 318, respectively.
Buffered by The handset device 300 can be placed in a separate container for a mobile cellular phone, or in a common container for a portable cellular phone with the transceiver 100 and the voice / logic control device 200. Can be.

Next, referring to the circuit diagram of FIG. 4, the switching IF of FIG.
4 illustrates a detailed circuit constructed by a preferred embodiment of the filter 150. The switching IF filter 150 is the first filter 4
08 and a second filter 410, which control the bandwidth control signal 9
Selected by 08. The output of the second mixer 148 is coupled to a buffer amplifier 402, whose output is applied to the input of an analog switch 404. In the preferred embodiment, analog switch 404 is a Motorola MC14551 CMOS analog switch integrated circuit. Analog switch 40
4 has a first switch 405 and a second switch 406,
Either the filter 408 or the second filter 410 is a detector
Combine with 152. When the bandwidth control signal 908 is a binary one, the first filter 408
To the detector 152. When the bandwidth control signal 908 is a binary 0 state, the second filter 410 is coupled to the detector 152 by the analog switch 404. In the preferred embodiment, the first filter 408 is a 455 KHz ceramic filter with a wide bandwidth, i.e., a 3 dB bandwidth of ± 12 KHz, and the second filter 410 has a narrow bandwidth, i.e., a 3 dB bandwidth of ± 6 KHz. 455 KHz ceramic filter.

Next, the flow diagram of FIG. 5 illustrates the microcomputer 202 in the audio logic control device 200 of FIG. 2 controlled by the first part of the control program for the cellular system A.
1 illustrates a signaling process and a communication process performed by the communication device. Initially, the display device 304 in the handset device 300 is provided with a pre-selected message indicating system A operation, which is subsequently cleared in response to the first key operation. The flow diagram of FIG. 5 enters block 502 in response to either an interrupt, a reset signal, or a return from system B. After initialization, a dedicated control channel is scanned at block 504,
The two strongest control channels are selected. If the service is not performed in the system A for a predetermined time, the control of the program is transferred to the second part of the control program in response to the interruption from the first part of the control program, and It is possible to operate on system B. For example, if a cellular telephone moves from an urban area covered by cellular system A to a highway or other urban area covered only by cellular system B, an out-of-service condition occurs. In this state, the microphone computer 20 is provided by the characteristics of the present invention.
2 branches back to the second part of the control program and resumes operation in cellular system B, so that cellular service is not interrupted. If a control channel is selected, the paging channel is scanned at block 506 to select the two strongest paging channels. If the service is provided, a series of overhead messages (Overhea) sent on the paging channel
ad message (OHM) is confirmed at block 508, after which program control proceeds to wait block 510. From the wait block 510, the start of the call in block 512 can occur, and the end of the call that has been registered and arrived in block 516 can be handled in block 514. From block 512 or block 514, program control proceeds to blocks 518, 520 and 522 to process the start or end of the call, respectively. At block 518, system access and conversation monitoring is performed, and if necessary, a handoff is performed at block 522, or, if service is lost, a clearing function to hang up and hang up the phone at block 520. Done. If the call has ended, program control returns to block 504 and repeats the process described above.

Next, FIG. 6 shows the microcomputer 202 of the voice / logic control device 200 shown in FIG. 2 controlled by the second part of the control program for signaling and communication in the cellular system B.
Shows the process performed by Processing commences in response to the interrupt at block 602 and initialization is performed.
During the operation of the system B, the “R”
The "OAM" indicator flashes constantly and the display 304 of the handset device 300 is provided with a preselected message indicating System B operation, which is subsequently cleared by the first key operation. Next, block 604
Then, the P channel is scanned, the RSSI signal 901 is detected, and the position code is confirmed. If the service is not performed on system B for a predetermined period, the program control
It is possible to move to the first part of the control program in response to an interrupt from the second part of the control program and resume the operation of the cellular system A as shown in FIG. At the time of such a program transfer, the current system parameters are stored in the EEPROM memory of the microcomputer 202 of the voice / logic controller 200, indicating that an operation in the cellular system B has been attempted. If the location code indicates that it has entered a new location,
At block 606, a location is registered. Otherwise, program control proceeds to wait block 608, where an outgoing call is initiated or an incoming call is terminated. Also, at block 608, the RSSI
The signal is continually checked to determine if an acceptable RF signal is being received. If the level of the RSSI signal 910 is lower than L2, program control
Return to 4. As long as the RSSI signal magnitude is greater than the L3 level, program control remains at block 608. In the preferred embodiment, levels L2 and L3 correspond to RF signal levels of -96 dBm and -91 dBm, respectively. Wait block 60
From block 8, an outgoing call is initiated at block 612, or termination of the incoming call is performed at block 614. From block 612 or block 614, program control proceeds to blocks 618, 620 and 622 to process the start or end of the call, respectively. At block 618, RSSI and conversation monitoring are performed, and if necessary, a handoff is performed at block 622, or, if no service is provided, a clearing function is performed at block 620 to hang up and hang up the telephone. If the call has ended, program control returns to block 608 to repeat the process described above.

The flowchart of FIG. 7 then illustrates the process performed by microcomputer 202 of voice / logic controller 200 of FIG. 2 to handle interrupts and automatic switching between cellular system A and cellular system B. 3
Two programmable timers, a Z timer, an X timer, and a Y timer, are used to determine when to switch between System A and System B. The Z timer is used to time the system A service loss. The optimal value for the Z timer is 20 seconds. The X timer is used to time the system B service loss. The optimal value of the X timer is 10 seconds. The Y timer is used to time the duration of System B services. The optimal value of the Y timer is 5
Minutes. During system A or system B initialization, the Z timer or the X and Y timers are set to their respective nominal values and then decremented in response to a one millisecond interrupt as described below. dual·
In the preferred embodiment of the cellular telephone of the system, automatic switching can be disabled, and system A and system B
Switching between and can also be performed manually in response to a preselected sequence of keys entered by the user on keypad 306.

In response to a one millisecond interrupt from the control program for cellular system A, the flow diagram of FIG. 7 is entered and the interrupt timer is checked at block 702 to determine if five milliseconds have elapsed. If the service has not been provided on system A after 5 ms, the Z timer is decremented at block 704. If service is provided on system A, the Z timer is set again to its nominal value. If a call has been initiated or is in progress, no switch between systems A and B will occur until the ongoing call is terminated. Next, at block 706, a status check is performed to determine if the Z timer has been decremented to zero. At this point, when the service is not provided on system A, or when service is first detected on system B, block 706 is reached and system A is checked again before switching to system B. According to the present invention, a switch to system B occurs only when a service is first detected in system B and then not detected in system A. This unique operation prevents the selection of system B when it comes out of a tunnel, surrounding garage, etc., into an area where both the preferred system A and the alternative system B are provided. If the Z timer has decremented to zero, then at block 708, the X and Y timers are set to their respective nominal values, and the system A call parameters are saved. Thereafter, upon returning from the one millisecond interrupt, the operation is switched to system B by branching to the second part of the control program.

In response to a one millisecond interrupt from the control program for cellular system B, the flow diagram of FIG. 7 is entered and the interrupt timer is checked at block 702 to determine if five milliseconds have elapsed. If 5 milliseconds have elapsed and no service has been provided at system B, the X timer is decremented at block 704. If service is provided on system B, the X timer is set again to its nominal value. If a call has been initiated or is in progress, no switch between systems A and B will occur until the ongoing call is terminated. Next, at block 706, a status check is performed to determine whether the X or Y timer has been decremented to zero, or whether the service is first provided on system B after not being detected on system A. I do. If the X or Y timer is decremented to zero, or if service is first provided on system B after not being detected on system A, then, at block 710, the Z timer is set to the nominal value. , System B call parameters are saved. Thereafter, when returning from the 1 millisecond interrupt, the operation branches to the first part of the control program, whereby the operation is performed in the system A.
Is switched to Since it is desirable to operate on system A, even if the service is provided on system B, the Y timer decrements to zero, and is switched to system A as a result. If there is no suitable system, only Z timer and X timer are needed in other embodiments.

In summary, a unique dual system cellular telephone has a bandwidth switching mechanism in the telephone receiver and a software switching mechanism in the controller for automatic operation in different cellular telephone systems.
Bandwidth switching can be accomplished by switching different filters in the intermediate frequency stage of the dual system cellular telephone receiver, depending on which cellular telephone system is available. Software switching can be accomplished by switching different parts of the control program of the dual system cellular telephone controller, depending on which cellular telephone system is available. If service is not available on one of the cellular telephone systems, this unique dual system cellular telephone automatically switches to the other cellular telephone system.

[Brief description of the drawings]

FIG. 1 is a block diagram of a transceiver of a cellular telephone embodying the present invention. FIG. 2 is a block diagram of a voice / logic device for a cellular telephone embodying the present invention. FIG. 3 is a block diagram of a handset device of a cellular telephone embodying the present invention. FIG. 4 is a circuit diagram of a switching IF circuit of the cellular transceiver of FIG. FIG. 5 is a flow diagram of a process used by the microcomputer 202 of FIG. 2 to perform signal processing and communication in the cellular system A. FIG. 6 is a flow diagram of a process used by the microcomputer 202 of FIG. 2 to perform signal processing and communication in the cellular system B. FIG. 7 is a flow diagram of a process used by the microcomputer 202 of FIG. 2 to perform interrupt and switch processing between the cellular system A and the cellular system B. 100 Transceiver, 102 Reference oscillator, 104 Synthesizer, 106 Splitter, 108 Offset voltage controlled oscillator, 110 Offset mixer, 112 Amplifier, 132 RF amplifier, 142 ... IF amplifier, 114 ... Directional coupler, 118,124,128,136 ... Transmission line, 120 ... Antenna, 116 ... Injection, filter, 122 ... Harmonic filter, 126 ... Transmit duplex filter, 130 ... Receive 2 Heavy filter, 134: Receiver filter, 140, 144: Crystal filter, 150: Switchable IF filter, 138: First mixer, 148: Second mixer, 146: Second local oscillator, 152: Detection 200, audio / logic device, 202, microcomputer, 204, EPROM memory, 206, EEPROM memory, 208, signal circuit, 210, audio circuit, 212, receiver filter, 214 ... Limiter, 216… Transmitter filter, 218 DC control circuit, 300 Handset device, 302 Microcomputer, 304 Display device, 306 Keypad, 308, 312 Amplifier, 310 Microphone, 314 Speaker 402: buffer amplifier, 404, 405, 406: analog switch, 408: first filter, 410: second filter.

Claims (18)

(57) [Claims] 1. A cellular telephone for performing a cellular telephone call using at least a first cellular telephone system and a second cellular telephone system, each having a different cellular radio channel, wherein the operation in the first cellular telephone system is the second cellular telephone. More preferably, the cellular telephone comprises: antenna means for receiving and transmitting cellular telephone call signals over said cellular radio channel; dial means for dialing digits of telephone numbers; A cellular transmission means coupled to antenna means for transmitting on a cellular radio channel of the telephone system and the second cellular telephone system; a cellular transmission means coupled to said antenna means for transmitting a cellular telephone call signal to the first and second cellular telephone systems; Cell to receive on cellular radio channel A first filter means having a predetermined first bandwidth, a second filter means having a predetermined second bandwidth smaller than the first bandwidth, and a first filter means, respectively. A cellular receiving means comprising intermediate frequency means having switching means responsive to a bandwidth control signal having a first state and a second state switching between the second filter means; and storing first and second control programs. Control means for automatically transmitting and receiving cellular telephone calls in a first cellular telephone system using a first control program and a second cellular telephone using a second control program. A system coupled to the dialing means, the cellular transmitting means and the cellular receiving means for automatically transmitting and receiving cellular telephone calls;
Generating a first state bandwidth control signal for a cellular telephone call in said first cellular telephone system;
Generating a second state bandwidth control signal for a cellular telephone call in a cellular telephone system; monitoring a cellular radio channel to detect that cellular service is not being performed; When the cellular service of the first cellular telephone system is not being performed during the second predetermined time interval of
When switching to the cellular telephone system and when the cellular service of the second cellular telephone system is not performed in the first predetermined time interval, or when a third predetermined time interval has elapsed since the switching to the second cellular telephone system. Control means for switching from the second cellular telephone system to the first cellular telephone system. 2. The cellular telephone of claim 1 wherein said first and second filter means include first and second ceramic filter means, respectively. 3. The cellular telephone according to claim 1, wherein said switching means comprises analog switching means. 4. An amplifying means for amplifying a cellular telephone call signal in response to a gain control signal, a means for detecting the magnitude of the amplified cellular telephone call signal, and an amplified cellular telephone. 2. The cellular telephone according to claim 1, further comprising means for generating a gain control signal in response to the detected magnitude of said call signal. 5. The cellular receiving means further includes an instruction signal generating means having an indication value of the strength of the cellular radio channel being received, and when the value of the indication signal is smaller than a predetermined value, the control means makes the cellular service available. 2. The cellular telephone according to claim 1, wherein it is detected that the call is not being performed. 6. The control means being cellular when a predetermined channel control signal is not received on at least one cellular radio channel. 2. The cellular telephone according to claim 1, wherein it is detected that the service is not being performed. 7. A cellular telephone for performing a cellular telephone call using at least a first cellular telephone system and a second cellular telephone system, each having a different cellular radio channel, wherein the operation in the first cellular telephone system is the second cellular telephone. More preferably, the cellular telephone comprises: an antenna means for receiving and transmitting a cellular telephone call signal over the cellular radio channel; a transmitter coupled to the antenna means for filtering the cellular telephone call signal to be transmitted Filter means; receiver filter means coupled to the antenna means for filtering the received cellular telephone call signal; dial means for dialing the digits of the telephone number; coupled to the transmitter filter means for filtering the cellular telephone call signal. Security of the first and second cellular telephone systems A cellular transmitting means for transmitting on a cellular radio channel; a cellular receiving means coupled to said receiver filter means for receiving a call signal of a cellular telephone on a cellular radio channel of a first cellular telephone system and a second cellular telephone system; First filter means having a predetermined first bandwidth, second filter means having a predetermined second bandwidth smaller than the size of the first bandwidth, and between each of the first filter means and the second filter means. A cellular receiving means comprising intermediate frequency means having a switching means responsive to a bandwidth control signal having a first state and a second state switched at the same time; and control means having a memory means for storing first and second control programs. Transmitting and receiving a cellular telephone call automatically in a first cellular telephone system using a first control program. It said dial means, coupled to said cellular transmitting means and the cellular receiver means to automatically send and receive calls cellular telephone in the second cellular telephone system using a second control program with,
A first state bandwidth control signal is generated for a cellular telephone call on the first cellular telephone system and a second state bandwidth control signal is generated for a cellular telephone call on the second cellular telephone system. Monitoring the cellular radio channel to detect that no cellular service is being provided, and wherein the cellular service of the first cellular telephone system is not being provided in at least two non-consecutive second predetermined time intervals. At the time of switching from the first cellular telephone system to the second cellular telephone system, and when the cellular service of the second cellular telephone system is not being performed at the first predetermined time interval, or at the time of switching to the second cellular telephone system When the third predetermined time interval elapses from the second
Control means for switching from a cellular telephone system to a first cellular telephone system. 8. The cellular telephone according to claim 7, wherein said first and second filter means include first and second ceramic filter means, respectively. 9. The cellular telephone according to claim 7, wherein said switching means includes analog switching means. 10. The cellular transmission means in response to a gain control signal, amplifying means for amplifying a cellular telephone call signal, means for detecting the magnitude of the amplified cellular telephone call signal, and the amplified cellular telephone signal. The cellular telephone of claim 7, further comprising means for generating a gain control signal in response to the detected magnitude of the telephone call signal. 11. The cellular receiving means further includes an indication signal generating means having an indication value of the strength of the cellular radio channel being received, and when the value of the indication signal is smaller than a predetermined value, the control means sets the cellular service. 8. The cellular telephone according to claim 7, wherein it is detected that the call is not being performed. 12. The control means being cellular when a predetermined channel control signal is not received on at least one cellular radio channel. The cellular telephone according to claim 7, wherein the cellular phone detects that the service is not being performed. 13. A cellular telephone for performing a cellular telephone call using at least a first cellular telephone system and a second cellular telephone system, each having a different cellular radio channel, wherein the operation in the first cellular telephone system is the second cellular telephone. More preferably, the cellular telephone comprises: antenna means for receiving and transmitting cellular telephone call signals over said cellular radio channel; dial means for dialing digits of telephone numbers; A cellular transmission means coupled to antenna means for transmitting on a cellular radio channel of the telephone system and the second cellular telephone system; a cellular transmission means coupled to said antenna means for transmitting a cellular telephone call signal to the first and second cellular telephone systems; Receive on a cellular radio channel Ruler receiving means, said cellular receiving means having: a first filter means having a predetermined first bandwidth, a first intermediate frequency means for generating a first intermediate frequency signal; and a predetermined second bandwidth. A second intermediate frequency means having a second filter means and a third filter means having a predetermined third bandwidth which is a band narrower than the second bandwidth, wherein the second intermediate frequency means is coupled to the first intermediate frequency signal and has two intermediate frequencies. Second intermediate frequency means for generating a frequency signal; detecting means coupled to the second intermediate frequency signal for detecting a received cellular telephone call signal; and in response to a bandwidth control signal having first and second states. Switching means for switching between a second filter means and a third filter means; and a control means having a memory means for storing first and second control programs, the first control means comprising: Automatically send and receive cellular telephone calls on a first cellular telephone system using a program and automatically transmit and receive cellular telephone calls on a second cellular telephone system using a second control program Coupled to the dialing means, the cellular transmitting means and the cellular receiving means for
Generating a first state bandwidth control signal for a cellular telephone call in said first cellular telephone system;
Generating a second state bandwidth control signal for a cellular telephone call in a cellular telephone system, monitoring a cellular radio channel to detect that cellular service is not being performed, at least twice non-continuously When the cellular service of the first cellular telephone system is not being performed during the second predetermined time interval of
When switching to the cellular telephone system and when the cellular service of the second cellular telephone system is not performed in the first predetermined time interval, or when a third predetermined time interval has elapsed since the switching to the second cellular telephone system. Control means for switching from the second cellular telephone system to the first cellular telephone system. 14. The cellular telephone according to claim 13, wherein said first and second filter means include first and second ceramic filter means, respectively. 15. The cellular telephone according to claim 13, wherein said switching means comprises analog switching means. 16. Amplifying means for amplifying a cellular telephone call signal in response to a gain control signal, said cellular transmitting means comprising:
The apparatus further comprises means for detecting the magnitude of the amplified cellular telephone call signal and means for generating a gain control signal in response to the detected magnitude of the amplified cellular telephone call signal. 13. The cellular telephone according to 13. 17. The cellular receiving means further includes an indication signal generating means having an indication value of the strength of the cellular radio channel being received, and when the value of the indication signal is smaller than a predetermined value, the control means sets the cellular service. 14. The cellular telephone according to claim 13, wherein it is detected that the call is not being performed. 18. The control means being cellular when a predetermined channel control signal is not received on at least one cellular radio channel. 14. The cellular telephone according to claim 13, wherein the cellular phone detects that the service is not performed.