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R&D in Indian PSUs: My Experience

  • P. V. Ananda MohanEmail author
Chapter

Abstract

I was initiated into research at Applied Physics Laboratories, Andhra University to work in the area of thin films with specific task initially on the development of a thickness monitor for films formed using vacuum evaporation. In those days, universities did not introduce transistors in the curriculum. Only circuit design using vacuum tubes used to be taught and laboratories were equipped with the needed electronic components. The problem was to use reflectance of thin films as measure of thickness when aluminium is being deposited. Unfortunately, the light from the tungsten filament was much more than the reflected light of a source. In order to distinguish these two, one signal and another noise, the reflected beam needs to be made different in some way. One known solution was to use modulation for the source being beamed on the thin film on glass substrate by chopping it. Thus one is having a frequency component depending on the motor speed and number of holes on the circular disc connected to the axle of the motor through which light is sent to fall on the device under test. The job was to design a bandpass filter to select he needed frequency component and reject the huge noise (light from the filament). The whole process happens in few seconds to take the aluminium or other metal like tin, copper in a crucible kept in the heated filament.

References

  1. 1.
    Ananda Mohan PV (1975) Inverted transistors in a low-voltage PNPN device. Electronic Engineering, London, p 17Google Scholar
  2. 2.
    Ananda Mohan PV (1983) Design of PCM filters and sinx/x correction. Electronic Engineering, pp 31–32Google Scholar
  3. 3.
    Ananda Mohan PV (1975) Precision tuning of RC parallel-T notch filter. Proc. IEEE 63:1730CrossRefGoogle Scholar
  4. 4.
    Ananda Mohan PV, Jayakumar V (1976) Distributed RC null network tuning. Proc. IEEE 64:362–363CrossRefGoogle Scholar
  5. 5.
    Ananda Mohan PV (1976) The definition of Q of RC notch networks. Proc. IEEE 64:1439–1440CrossRefGoogle Scholar
  6. 6.
    Ananda Mohan PV (1979) A novel band-pass filter using the amplifier pole. IEEE J. Solid-State Circ 14:649–651CrossRefGoogle Scholar
  7. 7.
    Ananda Mohan PV (1980) Novel active filters using the amplifier pole. Electron Lett 16:378–380CrossRefGoogle Scholar
  8. 8.
    Ananda Mohan PV, Ramachandran V, Swamy MNS (1995) Switched capacitor filters: theory, analysis and design. Prentice-Hall International, LondonGoogle Scholar
  9. 9.
    Ananda Mohan PV (1987) New structures of MOSFET-C filters. Proc. IEEE 75:957–960CrossRefGoogle Scholar
  10. 10.
    Ananda Mohan PV (1990) Generation of OTA-C filter structures from active RC filter structures. IEEE Trans CAS 37:656–660CrossRefGoogle Scholar
  11. 11.
    Ananda Mohan PV (1995) New current-mode biquad based on friend-deliyannis active RC Biquad. IEEE Trans CAS Part II 42:225–228Google Scholar
  12. 12.
    Ananda Mohan PV (2002) Residue number systems: algorithms and VLSI architectures. Kluwer Academic Publishers, USACrossRefGoogle Scholar
  13. 13.
    Ananda Mohan PV (2003) Current mode signal processing. Birkhauser, USAzbMATHGoogle Scholar
  14. 14.
    Ananda Mohan PV (2012) VLSI analog filters: active RC, OTA-C and SC. Birkhäuser, USAzbMATHGoogle Scholar

Copyright information

© Springer Nature Singapore Pte Ltd. 2020

Authors and Affiliations

  1. 1.CDACBangaloreIndia

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