Dual-bandwidth cellular telephone

• US 5,020,092 A
• Filed: 08/24/1990
• Issued: 05/28/1991
• 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): Bost, Dwayne D.
• Application Number:
  US07/572,724
• Time in Patent Office: 277 Days
• Field of Search: 379/57-61, 379/63, 455/33, 455/34, 455/54, 455/56, 455/58, 455/77, 455/340, 455/188
• 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 a first set of cellular radio channels having a first cellular telephone signalling protocol and a second set of cellular radio channels having a second cellular telephone signalling protocol, 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;

synthesizing means for generating a reference signal;

cellular transmitting means coupled to the antenna means for transmitting cellular telephone call signals on said cellular radio channels;

cellular receiving means coupled to the antenna means and the reference signal for receiving cellular telephone call signals on said cellular radio channels, said cellular receiving further including intermediate frequency means having dual-bandwidth filtering means and switching means for generating an intermediate frequency signal having a predetermined frequency, the dual-bandwidth filtering means switchable between a first predetermined bandwidth including the predetermined frequency and 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 said dual-bandwidth filtering means between the first and second predetermined bandwidths, 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 said cellular radio channels using the control program, said control means generating the first state of the bandwidth control signal for cellular telephone calls on said first set of cellular radio channels and generating the second state of the bandwidth control signal for cellular telephone calls on said second set of cellular radio channels.

2. The cellular telephone according to claim 1, wherein said dual-bandwidth filtering means includes first filtering means having the first predetermined bandwidth and second filtering means having the second predetermined bandwidth.

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 power amplifying means responsive to a PA 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 PA control signal.

5. A cellular telephone communicating cellular telephone calls on a first set of cellular radio channels having a first cellular telephone signalling protocol and a second set of cellular radio channels having a second cellular telephone signalling protocol, 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;

synthesizing means for generating a reference signal;

cellular transmitting means coupled to the antenna means for transmitting cellular telephone call signals on said cellular radio channels;

cellular receiving means coupled to the antenna means and the reference signal for receiving cellular telephone call signals on said cellular radio channels, 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 dual-bandwidth second filtering means for generating a second intermediate frequency signal having a second predetermined frequency, the dual-bandwidth second filtering means switchable between a second predetermined bandwidth including the second predetermined frequency and 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 said dual-bandwidth second filtering means between the second and third predetermined bandwidths, 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 said cellular radio channels using the control program, said control means generating the first state of the bandwidth control signal for cellular telephone calls on said first set of cellular radio channels and generating the second state of the bandwidth control signal for cellular telephone calls on said second set of cellular radio channels.

6. The cellular telephone according to claim 5, wherein said dual-bandwidth second filtering means includes third filtering means having the second predetermined bandwidth and fourth filtering means having the third predetermined bandwidth.

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

8. A cellular telephone communicating cellular telephone calls on a first set of cellular radio channels having a first cellular telephone signalling protocol and a second set of cellular radio channels having a second cellular telephone signalling protocol, 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;

synthesizing means for generating a reference signal;

cellular transmitting means coupled to the transmitter filtering means for transmitting cellular telephone call signals on said cellular radio channels;

cellular receiving means coupled to the receiver filtering means and the reference signal for receiving cellular telephone call signals on said cellular radio channels, said cellular receiving means further including intermediate frequency means having dual-bandwidth filtering means and switching means for generating an intermediate frequency signal having a predetermined frequency, the dual-bandwidth filtering means switchable between a first predetermined bandwidth including the predetermined frequency and 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 said dual-bandwidth filtering means between the first and second predetermined bandwidths, 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 said cellular radio channels using the control program, said control means generating the first state of the bandwidth control signal for cellular telephone calls on said first set of cellular radio channels and generating the second state of the bandwidth control signal for cellular telephone calls on said second set of cellular radio channels.

9. The cellular telephone according to claim 8, wherein said switching means includes analog switch means.

10. The cellular telephone according to claim 8, wherein said cellular transmitting means further includes power amplifying means responsive to a PA 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 PA control signal.

11. The cellular telephone according to claim 8, wherein said dual-bandwidth filtering means includes first filtering means having the first predetermined bandwidth and second filtering means having the second predetermined bandwidth.

12. The cellular telephone according to claim 11, wherein said cellular transmitting means further includes power amplifying means responsive to a PA control signal for amplifying 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 PA control signal.