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Numerical Study on Frequency Up-conversion in USPR using MATLAB

  • Roh, Young-Su
  • Received : 2009.12.30
  • Accepted : 2010.06.10
  • Published : 2010.09.01

Abstract

In this paper, the O-mode ultrashort-pulse reflectometry (USPR) millimeter-wave signals that propagate into the plasma and cover a frequency bandwidth of 33-158 GHz are examined numerically using MATLAB. Two important processes are involved in the computation: the propagation of the USPR impulse signal through a waveguide and the frequency up-conversion using millimeter-wave mixers. These mixers are limited to intermediate frequency signals that are less than 500 mV; thus, it is necessary to disperse the impulse signal into a chirped waveform using the waveguide. The stationary phase method is utilized to derive a closed-form formula for a chirped waveform under the assumption that the USPR impulse is Gaussian. In the process of frequency up-conversion, the chirped waveform is mixed with the mixer LO signal, and the lower frequency components of the RF signal are removed using high pass filters.

Keywords

Chirped waveform;Frequency bandwidth;Frequency up-conversion;Method of stationary phase;Ultrashort-pulse reflectometry

References

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  1. Reconstruction of the Electron Density Profile in O-mode Ultrashort Pulse Reflectometry using a Two-dimensional Finite Difference Time Domain vol.27, pp.7, 2013, https://doi.org/10.5207/JIEIE.2013.27.7.052
  2. Improvement of Power Spectrum in Ultrashort Pulse Reflectometry Signals Using Three Chirp Configuration vol.28, pp.3, 2014, https://doi.org/10.5207/JIEIE.2014.28.3.051