The development of an 8 kbps GMSK-like modem for Mobitex

Author

Noel, D. Peter ; Dew, George ; Kumar, Sasi ; Fiala-Timlin, Marie ; Mann, Karl

Author_Institution

Gandalf Mobile Syst. Inc., Nepean, Ont., Canada

fYear

1991

fDate

9-10 May 1991

Firstpage

791

Abstract

The 1200/8000 b/s GMSK-like modem utilizing a digital signal processor (DSP) and the required support circuitry is being developed. The modem functions are implemented using a DSP-based assembler. Both data transmission speeds are accommodated and are user selectable depending upon the position of a hardware selection switch (prototype only). The design eliminates the need for external DSP memory, as both the transmit and receive software, each restricted in size to 512 words of 24 bits, will reside on the DSP while being used. The DSP forms the heart of the modem. The controller section makes use of an Intel microprocessor, RAM, PROM, EEPROM, a gate array to provide an interface to the radio, and a combination of a communications controller with EIA drivers to create a standard user terminal interface

Keywords

computerised signal processing; digital radio systems; minimum shift keying; mobile radio systems; modems; radio data systems; 1.2 kbit/s; 8 kbit/s; DSP-based assembler; EEPROM; EIA drivers; GMSK-like modem; Intel microprocessor; Mobitex; PROM; RAM; communications controller; data transmission speeds; digital signal processor; gate array; receive software; standard user terminal interface; transmit software; Assembly; Circuits; Communication system control; Data communication; Digital signal processing; Digital signal processors; Hardware; Modems; Radio control; Switches;

fLanguage

English

Publisher

ieee

Conference_Titel

Communications, Computers and Signal Processing, 1991., IEEE Pacific Rim Conference on

Conference_Location

Victoria, BC

Print_ISBN

0-87942-638-1

Type

conf

DOI

10.1109/PACRIM.1991.160859

Filename

160859