Motorola Corporation

Sharon E Phillips

Bruce C Eastmond

Scott N Carney

A method and communication system provide for automatic optimization of data throughput by adjusting the encoder to use a long packet length and an increased channel coding efficiency during periods of low error counts and a short packet length and an increased channel coding redundancy during periods of high error counts.

Method and system for automatic optimization of data throughput using

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.

Dual-bandwidth cellular telephone

A radio transceiver is disclosed for use in an SSB communication system having FM data capability. The dual-mode radio transceiver of the present invention includes a receiver capable of demodulating and deriving AFC from either (a) the voice channel having voice messages transmitted via single sideband amplitude modulation with a pilot carrier, or (b) the data channel having high speed data messages transmitted via narrowband frequency modulation in the same channel bandwidth. Furthermore, the dual-mode radio transceiver includes a transmitter capable of transmitting one of either of the above types of modulation on the appropriate channel, as determined by information received from the high speed data messages transmitted on the control channel.

Dual mode radio transceiver for an SSB communication system

A radio communications system is described in which analog voice signals are transmitted and received via single sideband amplitude modulation, and digital data signals are transmitted and received via narrowband frequency modulation in a single trunked radio system having dedicated channel bandwidths. The base station continuously transmits the FM signalling information on a dedicated control channel. The remote station transceiver initially acquires lock to the data channel FM carrier, which is then demodulated to determine the frequency of an assigned voice channel. The remote station then acquires lock to the single sideband pilot carrier on the appropriate voice channel. The controller incorporates a memory state for holding AFC for the mobile transmit frequency. In the preferred embodiment, the data channel incorporates 2400 bps FSK-FM data in a 6.25 KHz channel bandwidth, while the voice channel includes a reduced pilot carrier located below the voice band for AFC and AGC reference, and an audio subcarrier located above the voice band for low speed FM data within the same 6.25 KHz channel bandwidth.

SSB communication system with FM data capability

An automatic frequency control (AFC) circuit is disclosed for use in an SSB radio transceiver having the capability of transmitting and receiving SSB and FM data signals over any one of a number of communication channels having equal bandwidths. The dual-mode AFC circuit includes AFC circuitry which is capable of tracking the frequency of either: (a) a first radio frequency (RF) carrier having voice signals modulated via a signal sideband amplitude modulation within a first channel bandwidth by locking to the reduced pilot carrier transmitter with the SSB signals; or of (b) a second RF carrier having high speed data signals modulated by narrowband frequency modulation within the designated channel bandwidth. The AFC circuit also includes control circuitry to memorize the AFC control voltage during the time the mobile is transmitting, and to assist the acquisition of the FM data carrier by varying the AFC sweep rate on the signalling channel.

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Lake in the Hills, IL, United States of America

Sharon E Phillips