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This thesis describes the application of commercially available microprocessors and other VLSI devices to high-speed real-time digital correlation in spread spectrum and related communication applications. Spread spectrum communications are a wide-band secure communication system that generate a very broad spectral bandwidth signal that is therefore hard to detect in noise. They are capable of rejecting intentional or unintentional jamming, and are insensitive to the multipath and fading that affects conventional high frequency systems. The bandwidth of spread spectrum systems must be large to obtain a significant performance improvement. This means that the sequence rate must be fast and therefore very fast microprocessors will be required when they are used to perform spread spectrum correlation. Since multiplication cannot be performed efficiently by microprocessors considerable work, since 1974, has been published in the literature which is devoted to minimising the requirement of multiplications in digital correlation and other signal processing algorithms. These fast techniques are investigated and implemented using general-purpose microprocessors. The restricted-bandwidth problem in microprocessor-based digital correlator has been discussed. A new implementation is suggested which uses bit-slice devices to maintain the flexibility of microprocessor-based digital correlation without sacrificing speed. This microprocessor-based system has been found to be efficient in implementing the correlation process at the baseband in the digital domain as well as the post-correlation signal processing- demodulation, detection and tracking, especiaJIy for low rate signals. A charge coupled-device is used to obtain spectral density function. An all-digital technique which is programmable for any binary waveform and can be used for achieving initial acquisition and maintaining synchronisation in spread spectrum communications is described. Many of the practical implementation problems are discussed. The receiver performance, which is measured in terms of the acquisition time and the bit-error rate, is also presented and results are obtained which are close to those predicted in the system simulations

Year: 1983

OAI identifier:
oai:etheses.dur.ac.uk:698

Provided by:
Durham e-Theses

- (1976). (34) Texas Instruments,
- (1979). (43) The Am2900 Family Data Book. Advanced Micro Devices Inc.,
- (1979). (46) Bipolar Microprocessor Logic and Interface Data Book.
- (1980). (50) The TTL Data Book for Design Engineers,
- (1979). (53) Bipolar Memory Data Book, Fairchild Camera &: Instrument Corporation,
- (1976). (70) Texas Instruments, The Optoelectronics Data for Design Engineers,
- (1973). (71) "Spread Spectrum Communications,"
- (1978). (73) National Semiconductor, Television /Radio,
- (1979). (86)idem,"Synchronisation of a Spread Spectrum Receiver by a Microprocessor control system",
- (1979). (97) 'Motorola MC6803 Advance Information',
- 0.0., R.L.Veenkant, R.W.Broderson, and C.R.Hewes,"Comparison Between the CCD CZT and the Digital FFT",
- 5.5.2 Correlation Process The perf orm ance of the 2901 system in achieving the acquisition process depends strongly on the partial crosscorrelation function M-I La.
- (1978). 8080/8085 Assembly Language Programming, Adam Osborne &:
- A block diagram of simulator is shown in Figure (4.2). The system box represents the simulation of the 2901-system archi tecture as described in the previous chapter. The operation of the simulator is controlled by the simulator executive system 4-12
- (1978). A-9 (98) 'Motorola M6800 Microprocessor Programming Manual',
- (1967). A.,"Fourth-Generation Software",
- (1978). AI-Rawas,"Error-Signal Generation for P seudonoise Tracking Loop", Electronic Circuit and Systems,
- (1979). and B.J.Stanier,"Microprocessor Implementation of Number Theoretic Transforms", Electronic Circuits and Systems,
- (1977). and C.C.Chen,"Acquisition Time Performance of PN Spread Spectrum Systems",
- (1969). and C.M.Rader,"The Chirp Z-Transform Algorithm",
- (1974). and C.S.Burrus,"Fast Convolution Using Fermat Number Transforms with Application to Digital Filtering",
- (1975). and C.S.Burrus,"Number Theoretic Transforms to Implement Fast Digital Convolution"
- (1976). and D.D.Bass,"A SOO-stage CCD Transversal Filter for Spectral Analysis",
- (1979). and D.D.Buss,"Applications of CCD and Switched Capacitor Filter Technology",
- (1973). and D.Sauitt,"Microprogramming and Stack Architecture Ease the Minicomputer Programmer's Burden",
- (1978). and H.Grammuller,"Combined Acquisition and Fine Synchronisation System For Spread Spectrum Receivers Using A Tapped Delay Line Correlator",
- (1978). and J.H.Hernandez,"Microprogram Assemblers for owers,
- (1975). and J.Saver,"The ABes of CCDs",
- (1982). and M.Pandit,"A novel, Spread Spectrum Receiver Synchronisation Scheme Using a SA W-Tapped Delay Line",
- (1976). and N.J.Sloane,"Pseudo-Random Sequences and Arrays",
- (1975). and R.S.Simpson,"Probability of Error in Pseudonoise (PN)- Modulated Spread Spectrum Binary Communication Systems",
- (1959). and Radio Amateur",
- (1979). and S.N.Gupta,"Digital Communication Systems in Impulsive Atmospheric Radio Noise",
- (1974). and T.J.Stephens,"LSI Digital Correlation Detector",
- (1978). ASWE Serial Highway Simulator, Report,
- (1974). C.H.,''FORTH: A New Way to Program A Mini-computer",
- (1982). Coherent Spread Spectrum Systems,
- Communication in the Presence of Noise",
- (1966). Correlation Techniques,
- (1972). Correlation using Number Theoretic Transforms Since
- (1981). Design: Controllers and ALUs.
- (1964). Digital Communications: with Space Applications,
- (1978). E.H.,"A comment on: Probability of Error in PN-Modulated Spread Spectrum Binary Communications Systems",
- FUNCTION ORTA-1 g~ ____________________________ ~r ______________________ __ IIi ZI o H ter: -10 lL.J~ cr;o cr;1f' o u (f) (f) 0 0 cr;o Ulli (1) I g o ~~-------------------------------------------------------10•00
- (1976). G.,"Microprogramming Helps Squeeze More from your Equipment Dollar",
- (1964). G.F.,"Serial Synchronisation of Pseudonoise Systems",
- (1977). H.F.,"An Introduction to Programming the Winograd F ourier Transform Algorithm (WFT A)",
- (1974). H.P.,"Analysis of Dithering Loop for PN Code Tracking",
- (1971). I.G.," Autocorrelation Function and Spectrum of a Fit tered Pseudorandom Binary Sequences",
- I"> ) 1(~ 1! ~ bl y 8 ... v 7 ... ' 1, I.- 1/ 1 I.- 1)'1 "'-< ~ "
- I+n+T (5.12) which represents the correlation of M symbols al" a i +1 ••••••• , ai+M_1 of the receiver's replica with the M symbols si+l+T , •••• s.
- (1977). Introduction to Communication Systems,
- (1968). J.H.,"An Analysis of Pseudo-Randomness Properties of Subsequences of Long m-sequences",
- (1963). J.J.,"Delay-lock Tracking of Binary Signals",
- (1976). M.,"A Bit-Slice Architecture for Microprogrammable Machines",
- (1980). M.,"The Application of CCD's to Spread Spectrum Systems",
- (1980). Microcomputer Interfacing.
- (1980). Microcomputers for Engineers and Scientists,
- (1981). Microprogrammed Control and Reliable Design of Small Computers,
- Microprogramming Saves Software Compatibility,"
- (1980). Microprogramming: A Tutorial and Survey of Recent Developments",
- (1973). N.G.,"Performance and Synchronisation Considerations", 'Spread Spectrum Communications',
- OUTPUT ENABLE o '/4' 'B'
- (1967). P.A.W.Lews, and P.D.Welsh,"Application of the Fast Fourier Transform to Computation of Fourier Integrals, Fourier series, and Convolution Integrals",
- (1980). P.K.,"Receivers for the NAVSTAR Global Positioning System", lEE
- (1977). P.M.,"A Unified Analysis of Pseudonoise Synchronisation by Envelope Correlation",
- r-r- r- 0- r- ...- ..--I I
- (1979). R.,"Real-time Spectrum Analysis Using Hardware F ourier and Chirp-Z Tranasformation", The Radio &: Electronic Engineer,
- (1982). R.A.,"The Origins of Spread Spectrum Communications",
- (1967). R.B.,"Digital Communications on a Pseudonoise Tracking Link Using Sequence Inversion Modulation",
- S t D V and M.B.Pursley,"Crosscorrelation Properties arwa e, •• , of Pseudorandom and Related Sequences",
- (1976). S.,"On computing the Discrete Fourier Transform"
- S.,"Some Bilinear Forms Whose Multiplicative Complexity Depends on the Field of Constants",
- (1971). S.R.,"A Study in Microprogrammed Processors: A Medium Sized Microprogrammed Processor",
- (1969). S.S.,"On Practical Setting of Detection Thresholds",
- (1967). Shift Register Sequences,
- (1964). Spectrum Analysis" Hewlett-Packard Journal,
- (1973). Spread Spectrum Communications, "Applications and State-of-the-Art Equipments",
- (1976). Spread Spectrum Systems,
- (1976). Spread Spectrum Techniques,
- (1973). Systems Engineering,
- (1977). T.G.Lewis, "Implementing a Pseudorandom Number Generator on a Minicomputer",
- (1974). T.G.Rauscher,"Microprogramming: Perspective and Status If,
- td=Otpn~n 309 9Al 00BE362010 pnsn,te~d ata Hor pn~n *even 310 9BO 9B0013701It ctx13: brarlch
- TDC1023J Monolithic Digital Correlator" Preliminary Information,
- (1980). The Art of Computer Programming,
- (1974). The Fast Fourier Transform,
- (1982). The Potential Application of Analogue Matched and Adaptive Filters in Spread Spectrum Communications", The Radio and Electronic Engineer,
- (1978). Thompson,"The UNIX Time-Sharing System",
- (1965). Tukey,"An Algorithm for Machine Calculation of Complex Fourier Series",
- (1977). W.Cooley,"New Algorithms for Digital Convolution",
- (1966). W.J.,"A Comparison of Binary Delay-lock Tracking Loop Implementations",
- Winograd (20) developed a new algorithm for computing short length OFT's known as the Winograd Fourier transform algori thm (WFT A). This algori thm uses fewer multiplications than the FFT, and about the same number of addi tions (26).
- (1978). Y.,"Bit-Slice Microprogramming Saves Software Compatibility",
- (1977). Yiu,"Acquisition of Pseudonoise Signals by Recursion-Aided Sequential Estimation",

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