Skip to main content
Article thumbnail
Location of Repository

Modulation techniques for data superposition on amplitude-modulated signals

By Yazan Othman Ahmad Al-Jalili


Double-sideband amplitude-modulation is widely\ud used because of its simplicity in transmission and\ud reception, but in a number of applications the inclusion\ud of a data channel has become an additional requirement.\ud An additional data signal, transmitted with a normal AM\ud broadcast signal, can be used by a specially-equipped\ud receiver to provide for display and control functions.\ud The data signals should not impair the main broadcast\ud signals, and should be imperceptible to listeners with\ud ordinary radio receivers.\ud \ud The principles of a new modulation scheme, which\ud permits an additional data channel to be superimposed on\ud conventional DSB-AM signals without any bandwidth increase\ud or envelope distortion, are described in this thesis. The\ud proposed system uses combined amplitude/frequency modulation\ud to provide for the additional data channel. It is shown that bandlimitation may be preserved by frequency modulating the carrier with frequency-modulating functions\ud related to the complex zeros of the amplitude-modulating\ud signal.\ud \ud The performance of the new modulation technique is\ud assessed by computer simulation. The cross-talk between\ud the two channels due to multipath propagation is considered\ud to be a limiting factor. A novel complex filtering technique to detect complex zeros of realsignals is introduced and discussed. The distribution of the complex zeros of positive bandlimited signals is assessed experimentally, and the possible data rates of the proposed system are discussed

Publisher: School of Electronic & Electrical Engineering (Leeds)
Year: 1983
OAI identifier:

Suggested articles


  1. (1982). A method for superimposing data. on amplitude-modulated signals", doi
  2. (1973). A spectral theory for hybrid modulation", doi
  3. (1973). A unified approach to the design of optimum FIR linear-phase digital filters", doi
  4. An introduction to random signals and communication theory",
  5. Calculus and analytic geometry",
  6. (1980). Circuits and systems: a modern approach", Holt-Saunders,
  7. (1975). Communication systems", McGraw-Hill, 2nd edition,
  8. (1979). Data and identification signalling for future radio receivers",
  9. Digital filters",
  10. Frequency modulation receivers",
  11. (1977). Introduction to digital filters",
  12. (1968). Mathematical handbook of formulas and tables", doi
  13. (1980). Modern television bandwidth compression techniques",
  14. On sampling the zeros of bandwidth limited signals", doi
  15. propagation: sky-wave field-strength prediction",
  16. (1977). Radio circuits explained",
  17. (1953). Radio receiver design", doi
  18. Radio reception",
  19. (1968). Radio Society of Great Britain, "The radio communication handbook", 4th edition,
  20. radio-data: compatibility tests",
  21. radio-data: specification of BBC experimental transmissions 1982",
  22. (1976). Some technical aspects of spectrum utilisation",
  23. (1973). Telecommunications systems design, volume 1: transmission systems",
  24. The analytic signal representation of modulated waveforms", doi
  25. The design and applications of filters with complex coefficients", doi
  26. (1982). The impact of radio-data on broadcast receivers", doi
  27. (1981). The impact of radio-data on broadcast receivers", IERE Conference on: Radio receivers and associated systems, doi
  28. (1980). The zeros of entire functions: theory and engineering applications", doi
  29. (1966). Toward a unified theory of modulation, part I: phase envelope relationships", doi
  30. (1966). Toward a unified theory of modulation, part II: zero manipulation", doi
  31. (1982). Zero synchronous frequency modulation", International Broadcasting Convention,

To submit an update or takedown request for this paper, please submit an Update/Correction/Removal Request.