IEEE Paper Review: Implementation of a modem based on Quadrature Amplitude Modulation using TMS320C6201 DSP
Authors: N Dahnoun and D R Clewer
Publisher: IEEE
Published in: IEE Colloquium on DSP Chips in Real-Time Instrumentation and Display Systems
Location: Leicester, UK,
Date of Conference: 24 September 1997
Summary:
Modems have traditionally been used to enable data communications via PSTN. This is severely band limited channel, requiring use of highly bandwidth efficient modulation schemes such as Quadrature Amplitude Modulation (QAM) combined with forward error correction and data compression in order to achieve bit rates up to 56 Kbps. The advances in DSP technology have recently enabled these bits rate to be achieved in commercial equipment at a reasonable cost.TMS320C6201 device boasts a maximum of 1600 MIPS at a clock speed of 200 MHz which is said to be more than a magnitude faster than any other fixed-point DSP. Cable modems allowing 36 Mbps transmission rates could be implemented using the same. Each module in transmitter as well as receiver was tested individually by writing a test program to read data in from a file, run the module and write the results on an output file. The data output were compared with expected output to judge failure and success of the DSP processor. To conclude, it was found that programming large functions in C on the DSP processor is both quick and easier than programming in assembler
Link: http://ieeexplore.ieee.org/document/659698/
Patent Review: Method for generating modern transmission signals with quadrature amplitude modulation.
Application Number: 06/136733
Application Date: 04/27/1982
Filling Date: 04/02/1980
Inventors: Gockler, Heinz and Hofmeister, Hagen
Summary:
Authors: N Dahnoun and D R Clewer
Publisher: IEEE
Published in: IEE Colloquium on DSP Chips in Real-Time Instrumentation and Display Systems
Location: Leicester, UK,
Date of Conference: 24 September 1997
Summary:
Modems have traditionally been used to enable data communications via PSTN. This is severely band limited channel, requiring use of highly bandwidth efficient modulation schemes such as Quadrature Amplitude Modulation (QAM) combined with forward error correction and data compression in order to achieve bit rates up to 56 Kbps. The advances in DSP technology have recently enabled these bits rate to be achieved in commercial equipment at a reasonable cost.TMS320C6201 device boasts a maximum of 1600 MIPS at a clock speed of 200 MHz which is said to be more than a magnitude faster than any other fixed-point DSP. Cable modems allowing 36 Mbps transmission rates could be implemented using the same. Each module in transmitter as well as receiver was tested individually by writing a test program to read data in from a file, run the module and write the results on an output file. The data output were compared with expected output to judge failure and success of the DSP processor. To conclude, it was found that programming large functions in C on the DSP processor is both quick and easier than programming in assembler
Link: http://ieeexplore.ieee.org/document/659698/
Patent Review: Method for generating modern transmission signals with quadrature amplitude modulation.
Application Number: 06/136733
Application Date: 04/27/1982
Filling Date: 04/02/1980
Inventors: Gockler, Heinz and Hofmeister, Hagen
Summary:
The
present invention relates to a method for generating modem transmission
signals with quadrature amplitude modulation (QAM) in which scanned
values of elementary bandpass signals are formed in digitally coded
form, the elementary bandpass signals are weighted with coefficients
depending on the information to be transmitted and the modem
transmission signals are formed by superposition of the thus weighted
elementary bandpass signals. It
is therefore the object of the present invention to provide a method
for generating modem transmission signals which operates with less
calculating operations and thus enables the circuit to operate at a
greater speed and with greater accuracy. The above object is
accomplished according to one embodiment of the invention in that in a
method for generating modem transmission signals with quadrature
amplitude modulation (QAM). Another advantage of the invention is that in
the case of m-ASK where m=2, 3, 4, . . . the elementary bandpass
signals are additionally weighted with factors corresponding to the
amplitude stages characteristic for the information to be transmitted.
Link: http://www.freepatentsonline.com/4327439.html 
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