Motorola Corporation

Scott W Noble

Timothy M Burke

Thomas A Freeburg

Eric R Schorman

Paul Fielding Smith

Jay R Krebs

Charles N Lynk

A data signalling system for transmitting signals between at least one primary station and a plurality of secondary stations. The system is well adapted for use in multiple unit radio communications systems capable of noise and data communications. A register model is utilized which permits a highly flexible signalling system compatable with a wide range of communications networks. Data transfer is accomplished using fixed length data packets which are error correction encoded and transmitted utilizing PSK modulation.

Data signalling system

A general purpose data control and information system particularly well adapted for multiple unit radio communications providing reliable enhancement to normal voice systems. The system provides addressing capability along with data transfer and utilizes handshake and retransmission protocol to enhance flexibility and reliability. The system utilizes fixed length signalling packets, with error correction encoding, to permit data transfer, transmitter identification and control and status monitoring.

General purpose data control system

A selective calling, paging and priority signalling system for two way communications between at least one primary and a plurality of remote stations. An automatic selective calling mode is provided in which the primary station operator enters the address of the desired unit and activates his microphone. Unmuting data packet will then be transmitted to the addressed remote station, unmuting the remote station. When the transmission ends, a mute data packet is transmitted, remuting the remote station.

Selective call, paging and priority signalling system

A digital voice storage mobile control terminal adapted for use in multiple unit land mobile radio communications system. The mobile control terminal utilizes up to eight 64K dynamic RAMs to store up to 42 seconds of speech comprising up to eight separate messages as well as a CVSD encoder-decoder to digitize speech messages.

Digital voice storage mobile

A digital voice storage system adapted for use in a multiple unit land mobile radio communications system. The system utilizes a PSK signalling system with fixed length data packets to control a system capable of multiple message storage of speech at mobile stations. Up to eight 64K dynamic RAMS are used in conjunction with a microprocessor to store up to 42 seconds of speech comprising up to eight separate messages. In addition, the system permits base interrogation of mobiles to determine if a message has been stored for review by the base operator and to determine the remaining recording capacity and total recording capacity of the mobile.

Digital voice storage system

An improved digital demodulator and detector for phase-shift-keyed digital signals providing coherent detection with high sensitivity and stability on noisy channels. Digital sampling is used in conjunction with a digital phase locked loop system in which basic time increments are subtracted or added to an equilibrium timing loop to provide simultaneous carrier demodulation and bit recovery.

Digital coherent PSK demodulator and detector

A unique bit data operated squelch for use with a demodulator detector for phase shift keyed digital signals. The squelch detects transitions by testing a register of baseband demodulated sample synchronized to the data bit edges. The inventive data operated squelch provides bit detection with programmable parameters and is particularly suitable for implementation utilizing a microprocessor.

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Bedford, TX, United States of America

Scott W Noble