Multiplex techniques

Thermal desorption spectroscopy and temperature programmed reaction experiments have provided significant insight into the chemistry of a wide variety of reactions on well characterized surfaces. In such experiments, characterized, adsorbate covered, surfaces are heated at rates of 10-100 K/sec and molecular species which desorb are monitored by mass spectrometry. Typically, several masses are monitored in each experiment by computer multiplexing techniques. Often, in such experiments, the species desorbed are the result of a surface reaction during the temperature ramp. 

The noise should be reduced by cooling the detector and minimizing its effective area. Its influence can be reduced by employing multichannel and multiplex techniques, by accumulating spectra, and by increasing the measuring time. 

Now, the big difference between multichannel and multiplex techniques arises because a single detector in FT-Raman is collecting all the modulated wavelengths at once. Consider a single data acquisition in an FT experiment, with the interferometer at a fixed position. The detector collects light from... 

X.-D. Wang, T.J. Cardwell, R.W. Cattrall, R.R Dyson, G.E. Jenkins, Time-division multiplex technique for producing concentration profiles in flow analysis, Anal. Chim. Acta 368 (1998) 105. 

The term volume holography refers to recording plates with a thickness of up to a few millimeters. In such voluminous matrices, data storage in three dimensions is possible. This implies an enormous increase in storage capacity in comparison with other methods. If multiplexing techniques (see Section 12.1) are applied, thousands of holograms can be superimposed in the same plate. 

This criterion for gel-point detection, and the non-equilibrium nature of systems imdergoing gelation, requires that data be obtained rapidly over a wide range of frequeney, prompting the development of a frequeney multiplexing technique known as Fourier Transform Mechanical Spectroscopy, FTMS, which allows the measurement of G at several frequencies simultaneously, rather than eonseeutively, as in a conventional test [Holly et al., 1988]. 

The Hadamard multiplexing technique (Figure 2B) is also based on the dispersion of the transmitted radiation by the sample with a fixed optical element (identical to the diode array approach), while detection is carried out by means of a unique large bandpass detector. Mask displacement allows simultaneous intensity measurement on multiple spectral channels at different times. Spectrum reconstitution is achieved by solving the system of mathematical equation generated by the mask movement in time. 

Application of polarization multiplexing technique in holographic interferometer... 

Multiplexing Technique for addressing a matrix display whereby aU possible combinations of on and off pixels can be shown. 

Code-Division Multiplexing Technique that creates multiple channels from one physical channel by using code keys to create the channels. 

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