Dual-bandwidth cellular telephone

• US 4,972,455 A
• Filed: 06/23/1989
• Issued: 11/20/1990
• Est. Priority Date: 06/23/1989
• Status: Expired due to Term

• Current Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Carney, Scott N., Phillips, Sharon E. T.
• Primary Examiner(s): Ng, Jin F.
• Assistant Examiner(s): Shehata, Magdy
• Application Number:
  US07/370,666
• Time in Patent Office: 515 Days
• Field of Search: 379/58, 379/59, 379/60, 379/61, 379/63, 379/57, 455/33, 455/34, 455/54, 455/58, 455/56, 455/188, 455/168, 455/76
• US Class Current: 455/552.1
• CPC Class Codes: H04B 1/406 with more than one transmission mode, e.g. analog and digital modes
• CPC Class Codes: H04W 88/06 adapted for operation in multiple networks or having at least two operational modes, e.g. multi-mode terminals

Abstract

A unique dual-bandwidth cellular telephone includes a transceiver (100) having a dual bandwidth receiver, an audio/logic unit (200) having dual control programs, and a handset unit (300). The dual bandwidth receiver of the transceiver (100) has different filters (408 and 410) in the intermediate frequency section thereof which are switchably selected depending on which cellular telephone system is available. When service is not available in one of the cellular telephone systems, the unique cellular telephone automatically switches the receiver bandwidth and control program for operating on the other cellular telephone system.

Claims

1. A cellular telephone communicating cellular telephone calls on at least first and second cellular telephone systems each having different cellular radio channels, said cellular telephone comprising:

antenna means for receiving and transmitting cellular telephone call signals on said cellular radio channels;

dialing means for dialing digits of telephone numbers;

cellular transmitting means coupled to the antenna means for transmitting cellular telephone call signals on the cellular radio channels of the first and second cellular telephone systems;

cellular receiving means coupled to the antenna means for receiving cellular telephone call signals on the cellular radio channels of the first and second cellular telephone systems, said cellular receiving means further including intermediate frequency means having first filtering means, second filtering means and switching means for generating an intermediate frequency signal having a predetermined frequency, the first filtering means having a first predetermined bandwidth including the predetermined frequency, the second filtering means having a second predetermined bandwidth the includes the predetermined frequency and has a magnitude less than that of the first predetermined bandwidth, and the switching means being responsive to a bandwidth control signal having first and second states for switching between the first and second filtering means, respectively; and

control means including memory means for storing a control program, said control means being coupled to the dialing means, cellular transmitting means, and cellular receiving means for automatically transmitting and receiving cellular telephone calls on the first and second cellular telephone systems using the control program, said control means generating the first state of the bandwidth control signal for cellular telephone calls on said first cellular telephone system and generating the second state of the bandwidth control signal for cellular telephone calls on said second cellular telephone system.

2. The cellular telephone according to claim 1, wherein said first and second filtering means include first and second ceramic filter means.

3. The cellular telephone according to claim 1, wherein said switching means includes analog switch means.

4. The cellular telephone according to claim 1, wherein said cellular transmitting means further includes amplifying means responsive to a gain control signal for amplifying the cellular telephone call signals, means for detecting the magnitude of the amplified cellular telephone call signals, and means responsive to the detected magnitude of the amplified cellular telephone call signals for generating the gain control signal.

5. A cellular telephone communicating cellular telephone calls on at least first and second cellular telephone systems each having different cellular radio channels, said cellular telephone comprising:

antenna means for receiving and transmitting cellular telephone call signals on said cellular radio channels;

transmitter filtering means coupled to the antenna means for filtering the transmitted cellular telephone call signals;

receiver filtering means coupled to the antenna means for filtering the received cellular telephone call signals;

dialing means for dialing digits of telephone numbers;

cellular transmitting means coupled to the transmitter filtering means for transmitting cellular telephone call signals on the cellular radio channels of the first and second cellular telephone systems;

cellular receiving means coupled to the antenna means for receiving cellular telephone call signals on the cellular radio channels of the first and second cellular telephone systems, said cellular receiving means further including intermediate frequency means having first filtering means, second filtering means and and switching means for generating an intermediate frequency signal having a predetermined frequency, the first filtering means having a first predetermined bandwidth including the predetermined frequency, the second filtering means having a second predetermined bandwidth that includes the predetermined frequency and has a magnitude less than that of the first predetermined bandwidth, and the switching means being responsive to a bandwidth control signal having first and second states for switching between the first and second filtering means, respectively; and

control means including memory means for storing a control program, said control means being coupled to the dialing means, cellular transmitting means, and cellular receiving means for automatically transmitting and receiving cellular telephone calls on the first and second cellular telephone systems using the control program, said control means generating the first state of the bandwidth control signal for cellular telephone calls on said first cellular telephone system and generating the second state of the bandwidth control signal for cellular telephone calls on said second cellular telephone system.

6. The cellular telephone according to claim 5, wherein said first and second filtering means include first and second ceramic filter means, respectively.

7. The cellular telephone according to claim 5, wherein said switching means includes analog switch means.

8. The cellular telephone according to claim 5, wherein said cellular transmitting means further includes amplifying means responsive to a gain control signal for amplifying the cellular telephone call signals, means for detecting the magnitude of the amplified cellular telephone call signals, and means responsive to the detected magnitude of the amplified cellular telephone call signals for generating the gain control signal.

9. A cellular telephone communicating cellular telephone calls on at least first and second cellular telephone systems each having different cellular radio channels, said cellular telephone comprising:

antenna means for receiving and transmitting cellular telephone call signals on said cellular radio channels;

dialing means for dialing digits of telephone numbers;

cellular transmitting means coupled to the antenna means for transmitting cellular telephone call signals on the cellular radio channels of the first and second cellular telephone systems;

cellular receiving means coupled to the antenna means for receiving cellular telephone call signals on the cellular radio channels of the first and second cellular telephone systems, said cellular receiving means further including;

first intermediate frequency means including first filtering means for generating a first intermediate frequency signal having a first predetermined frequency, the first filtering means having a first predetermined bandwidth including the first predetermined frequency;

second intermediate frequency means coupled to the first intermediate frequency signal and including second filtering means and third filtering means for generating a second intermediate frequency signal having a second predetermined frequency, the second filtering means having a second predetermined bandwidth including the second predetermined frequency, the third filtering means having a third predetermined bandwidth that includes the second predetermined frequency and has a magnitude less than that of the second predetermined bandwidth;

detecting means coupled to the second intermediate frequency signal for detecting the received cellular telephone call signals; and

switching means responsive to a bandwidth control signal having first and second states for switching between the second and third filtering means, respectively; and

control means including memory means for storing a control program, said control means being coupled to the dialing means, cellular transmitting means, and cellular receiving means for automatically transmitting and receiving cellular telephone calls on the first and second cellular telephone systems using the control program, said control means generating the first state of the bandwidth control signal for cellular telephone calls on said first cellular telephone system and generating the second state of the bandwidth control signal for cellular telephone calls on said second cellular telephone system.

10. The cellular telephone according to claim 9, wherein said first and second filtering means include first and second ceramic filter means, respectively.

11. The cellular telephone according to claim 9, wherein said switching means includes analog switch means.

12. The cellular telephone according to claim 9, wherein said cellular transmitting means further includes amplifying means responsive to a gain control signal for amplifying the cellular telephone call signals, means for detecting the magnitude of the amplified cellular telephone call signals, and means responsive to the detected magnitude of the amplified cellular telephone call signals for generating the gain control signal.