Mean signal frequency

Using this, one can easily calculate the mean signal frequency v (i.e., the mean count rate without dead time) from the measured value of the mean count rate vg (i.e., the apparent mean signal frequency) provided that 6 is known ... 

The capacitance behavior is strongly dependent on the contributing surface position in the electrode [50], If the considered surface lays deep into carbon micropores, the access time for the ions to this area will be longer and more resistive than for external carbon surfaces. In other words, it means that the deep internal areas are relatively inaccessible for short-electric impulses or for high-frequency currents. These deep surfaces contribute to the capacitance with a high RC time constant. As a result, the capacitance amplitude drops with increasing signal frequency. 

Practically this means that high signal frequencies are detected at bright illumination while poor illumination results in low-pass filtering in each pixel. Log amplification inserts an amplification noise proportional to the amplification factor. In contrast, exponential attenuation results in a constant SNR over most of the range because the noise is proportional to the square root of Af Fig. 7.8.6 shows the difference in dynamic behavior of a CCD and a nonlinear CMOS sensor. 

More importantly, the result of this integration is zero for all other signal frequencies. This means that the PSD very effectively rejects noise and other undesired signal components it only detects the signal of interest, i.e., any signal that has the same frequency as the reference signal. The output of the PSD is further amplified and converted into a digital value by an A/D converter in the FRA. 

An interesting realization of a widely tunable OPO is a fiber OPO pumped by a fiber laser. One example is the sub-1 pm operation of a fiber OPO in a fiber ring resonator, pumped by an all-fiber master oscillator plus power amplifier based on a photonic crystal fiber as gain medium [592], A conversion efficiency of 8 6 % from the pump at 1079nm to the anti-Stokes signal at 715nm. This means a frequency shift of 142 THz between pump and anti-Stokes signal. 

TNgUlfOg is the duration of the signal, which in turn depends on the mean circular frequency cOg and number of cycles Ng of the ground motion. As an example, for Gig = 12.5 rad/s and Ng = 8.25, the duration of the signal is tg = 4.15 s. The accelerogram obtained with this set of parameters is shown within Fig. la, in which the red half sine gives the envelope. 

Spectrometers have been built around this phenomenon to simplify complicated spectra. For example, instead of Stark modulation, the pump source may be modulated, and this modulatates the signal absorption by means of the double-resonance effect. A narrowband amplifier tuned to the modulation frequency is employed along with the usual phase-sensitive detector. A simplified version of such a spectrometer is shown in Fig. 12. Clearly, as the signal frequency is swept, only transitions with a common energy level with the fixed pump will be modulated and observed, thus greatly simplifying the spectrum. For... 

Once a slice has been selected and excited, it is necessary to encode the ensuing NMR signal with the coordinates of nuclei within the slice. For each coordinate (x andy) this is achieved by one of two very closely related means, frequency encoding or phase encoding [1]. In this section we consider the fonner and in the next, the latter. In tlie section after that we show how the two are combined in the most coimnon imaging experiment. 

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