Manchester encoded bandpass sigma–delta modulation for RF class D amplifiers

Manchester encoded bandpass sigma–delta modulation for RF class D amplifiers

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An analysis of a continuous-time bandpass sigma–delta modulator in a configuration with an upconverter is given for a RF class D amplifier application. The upconverter multiplies the modulator pulse train with a synchronised clock signal and maps each modulator bit to an integer multiple k of a (+1, −1) or (−1, +1) pattern depending on the sign of the modulator bit. The upconversion is equivalent to an extension of Manchester encoding, which is usually defined for k=1. The analysis focuses on evaluating the impact of upconversion on the modulator coding efficiency and the average pulse period. A design equation is derived, which shows that coding efficiency is dependent only on the upconversion frequency ratio, while the average pulse period depends only on k. The equations provide a designer with a way of evaluating the trade-offs in the amplifier system and show that encoding with k=1 is the most efficient configuration for maximising coding efficiency and minimising switching power loss.


    1. 1)
    2. 2)
      • Johnson, T., Stapleton, S.: `Available load power in a RF class D amplifier with a sigma-delta modulator driver', Proc. IEEE Radio and Wireless Conf., September 2004, Atlanta, GA, USA, p. 439–442.
    3. 3)
      • Wagh, P., Midya, P., Rakers, P., Caldwell, J., Schooler, T.: `An all-digital universal RF transmitter', Proc IEEE Custom Integrated Circuits Conf., October 2004, Orlando, FL, USA, p. 549–552.
    4. 4)
      • Shoaei, O., Snelgrove, W.M.: `Optimal (bandpass) continuous-time ΣΔ modulator', Proc IEEE Int. Symp. on Circuits and Systems, 30 May–2 June 1994, London, UK, 5, p. 489–492.
    5. 5)
      • Thurston, A., Pearce, T.H., Hawksford, M.J.: `Bandpass implementation of the sigma-delta A-D conversion technique', Proc. IEE Int. Conf. on Analogue to Digital and Digital to Analogue Conversion, September 1991, Swansea, UK, p. 81–86.
    6. 6)
    7. 7)
      • Thomas, K., Rana, R.S., Yong, L.: `A 1 GHz CMOS fourth-order continuous-time bandpass sigma delta modulator for RF receiver front end A/D conversion', Proc. Asia and South Pacific Design Automation Conf. (ASP-DAC), January 2005, Shanghai, People's Republic of China, 2.
    8. 8)
      • H. Tao , J.M. Khoury . A 400-ms/s frequency translating bandpass sigma-delta modulator. IEEE Trans. Circuits Syst. I, Fundam. Theory Appl. , 12 , 665 - 670
    9. 9)
    10. 10)
    11. 11)
    12. 12)
      • Johnson, T., Stapleton, S., Cavers, J.: `Binary coding for RF class D amplifier applications', Proc. Ninth Canadian Workshop on Information Theory, June 2005, Montréal, Québec, Canada, p. 74–77.
    13. 13)
      • H.L. Kraus , C.W. Bostian , F.H. Raab . (1980) Solid-state radio engineering.
    14. 14)
      • S.C. Cripps . (1999) RF power amplifiers for wireless communications.
    15. 15)
      • L.W. Couch . (1997) Digital and analog communication systems.
    16. 16)
      • A. Papoulis . (1965) Probability, random variables, and stochastic processes.
    17. 17)
    18. 18)
      • H.F. Davis . (1963) Fourier series and orthogonal functions.

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