Information on programmable digital modems (PDM) is given in viewgraph form. Topics covered include data rate range and operational modes, test and demonstration equipment, program goals, modulation formats, and PDM design challenges

Kappes, M.

English

NASA Technical Reports Server

PROGRAMMABLE DIGITAL MODEM
M. Kappes
COMSAT Laboratories
Cl_ksburg, Maryland 20871
N92-22014
DATA RATE RANGE AND OPERATIONAL MODES
SYMBOL RATE RANGE OF PDM:
• 1.92 - 75 MSYMBOLS/S
OPERATIONAL MODES:
• CONTINUOUS
• DEPENDENT BURST
• INDEPENDENT BURST
TEST AND DEMONSTRATION EQUIPMENT
FEATURES;
• PROVIDES MULTIPLE DATA STREAMS FOR HIGHER LEVEL FORMATS
• INSERTS PREAMBLES AND UNIQUE WORD STRUCTURES FOR BURST MODES
• GENERATES DATA AND CONTROL SIGNALS FOR INTERFERRING BURST
MODULATOR
• PROVIDES CONTROL SIGNALS REQUIRED FOR DEMODUALTOR OPERATION
• MEASURES BER AND UNIQUE WORD MISS RATE
PRECEDING PAGE BLANK NOT F_LMED
219
https://ntrs.nasa.gov/search.jsp?R=19920012771 2020-03-17T13:14:02+00:00Z
DATA RATE RANGE AND OPERATIONAL MODES
SYMBOL RATE RANGE OF PDM:
• 1.92 - 75 MSYMBOLS/S
OPERATIONAL MODES:
• CONTINUOUS
• DEPENDENT BURST
° INDEPENDENT BURST
TEST AND DEMONSTRATION EQUIPMENT
FEATURES:
• PROVIDES MULTIPLE DATA STREAMS FOR HIGHER LEVEL FORMATS
• INSERTS PREAMBLES AND UNIQUE WORD STRUCTURES FOR BURST MODES
• GENERATES DATA AND CONTROL SIGNALS FOR INTERFERRING BURST
MODULATOR
• PROVIDES CONTROL SIGNALS REQUIRED FOR DEMODUALTOR OPERATION
• MEASURES BER AND UNIQUE WORD MISS RATE
220
PROGRAMMABLE DIGITAL MODEM
PROGRAM GOALS
DEVELOPMENT OF A MODEM WHICH IS:
• PROGRAMMABLE IN THE AREAS OF MODULATION
FORMAT, DATA RATE, AND OPERATIONAL MODE
• FULLY DIGITALLY IMPLEMENTED
• LOW RECURRING COST
• SMALL SIZE
MODULATION FORMATS
REQUIRED FORMATS:
• QPSK, 8-PSK, 16-PSK
OPTIONAL FORMATS:
• OFFSET QPSK
• MSK
• 16-QAM
221
PDM DESIGN CHALLENGES
DEMODULATOR AGC. CARRIER, AND CLOCK RECOVERY STRUCTURE:
• MUST BE ADAPTABLE TO HANDLE DIFFERENT MODULATION FORMATS
• RECOVERY BANDWIDTHS MUST SCALE WITH DATA RATE
• OPERATION AT 75 MSYMBOLS/S AND 2 SAMPLES (SYMBOL REQUIRES 150 MHZ
CLOCKING
• MINIMIZE POWER AND SIZE WHILE OPERATING AT THIS SPEED
DATA FILTERING:
• REQUIRES DIGITAL IMPLEMENTATION FOR DATA RATE FLEXIBILITY
• HIGH SPEED REQUIREMENT IMPOSES COMPLEXITY LIMIT ON FILTER
OPERATIONAL MODES:
• INDEPENDENT BURST MODE REQUIRES RATE FLEXIBLE ACQUISITION
ALGORITHMS
222
N/ A
Lewis Research Center
I II
AEROSPACE TI_CHNOtOOY _IIECTORATE
SESSION IV
POSTER DISPLAYS AND TECHNOLOGY REVIEWS
CHAIR: W.D. IVANCIC
J.M. OTT, FORD AEROSPACE CORP.
J.K. WONG AND E.M. MROZEK, TRW, INC.
R. FANG, M. KAPPES, AND S. MILLER, COMSA T LABS
J. V. WERNLUND, HARRIS CORPORA TION
C.R. RYAN, MOTOROLA, INC.
W. W. WU, INTELSA T
R.J. KERCZEWSKI, NASA LEWIS RESEARCH CENTER
II I I

ORIG1MAI. PAGE
BLACK AND WHITE PHOTOGRAPH
\
COMSAT Laboratories 225 Mb/s, Add-Compare-Select gate array test circuit and
poster display.
I
COMSAT laboratories rate 8/9 coded g-PSK proof-of-concept system and poster
display.
225
PRECEDING PAGE BLANK NOT FILMED
ORIGINAL PAGE
BLACK AND WHITE PHOTOGRAPt-4
Ford Aerospace 8-PSK demodulator poster display.
Harris Corporation rate 1/2 coded 16-CPFSK proof-of-concept demodulator and
special test equipment and poster display for ACTS LBR-2 Earth Station.
226
ORIGINAL_^_
BLACK AND WHITE PrIOTOGRAPH
TRW Incorporated rate 3/4 coded 16 QAM posters.
tJ 1_ - ,
NASA Lewis Research Center Systems Integration, Test and Evaluation (SITE)
Project poster display.
227
ORIGINALPAGE
BLACKAND WHITE PHOTOGRAPH
Panel Members: S. Joseph Campanella, Panel Chair (COMSAT Laboritories); Frank
Amoroso (Hughes Aircraft); Kamilo Feher (University of California); Peter Liu
(Cyclotomics); Carl R. Ryan (Motoroal Incorporated); A1 Stem (General Electric)
Motorola Incorporated display and demonstration of computer aided design of com-
munication systems.
228
Lewis Research Center al_OSPACl _CHHOLOGY _fCTO_A T!
l I I II
|[
SESSION V
OTHER ADVANCED MODULA TION AND
CODING PROGRAMS
CHAIR: J.L. HARROLD
A TDRSS 300 MB/S MODEM PROGRAM
C.R. RYAN
MOTOROLA, INCORPORA TED
MODULATION AND CODING TECHNOLOGY FOR DEEP SPACE
AND SA TELLITE APPLICA TIONS
J.H. YUEN AND W. RAFFERTY
CALIFORNIA INSTITUTE OF TECHNOLOGY
DIGITAL S YNCHRONIZA TION AND
COMMUNICA"i ION TECHNIQUES
W.C. LINDSEY
LINCOM CORPORA TION
I I I
v N
Lewis Research Center
AEROSPACE TECNNOLOO¥ D_RECTOAA T I;
SESSION V CONTINUED
BANDWIDTH EFFICIENT CODING FOR
SATELLITE COMMUNICA TIONS
SHU LIN
UNIVERSITY OF HAWAII
D.J. COSTELLO, JR.
UNIVERSITY OF NOTRE DAME
W.H. MILLER, J.C. MORAKIS, AND W.B. POLAND, JR.
GODDARD SPACE FLIGHT CENTER


Programmable digital modem

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