Signal-noise discrimination

AUTO/MANUAL threshold (may also be labelled AUTO/VAR). The BLR must distinguish between the gross baseline shift and deviations caused by noise on the input signal. This is achieved by setting a threshold below which the BLR is inactive. The AUTO switch position allows the BLR restorer to set its noise discriminator threshold automatically. MANUAL provides manual control of the threshold by means of a multi-turn potentiometer. 

The inherent noise discrimination by the VCO, which was cited in a preceding paragraph, may be understood from the so-called cyclic overlap fraction of the PLL. With both the input i.e., the now modified Si) and feedback signals of the loop taken to be square waves, a representative chronogram of the phase comparator component of fire PLL is shown in Figure 32. The output is a periodic signal... 

The oil saturation in the core was monitored with a scintillation counter equipped with a discriminator to increase the signal-noise ratio. The core could be traversed across the 14-in. lead collimator to scan for uniform saturation. The effluent water-oil ratio was also brought to equilibrium with the feed before the oil saturation was measured. 

Detectors. The function of the gc detector is to sense the presence of a constituent of the sample at the outlet of the column. Selectivity is the property that allows the detector to discriminate between constituents. Thus a detector selective to a particular compound type responds especially weU to compounds of that type, but not to other chemical species. The response is the signal strength generated by a given quantity of material. Sensitivity is a measure of the abiHty of the detector to register the presence of the component of interest. It is usually given as the quantity of material that can be detected having a response at twice the noise level of the detector. 

Larger frequency shifts lead to more sensitive structural discriminations. In the IR, the (i-shcct amide I is distinctively lower in frequency than other structural types, particularly for aggregates, a form often seen in unfolding experiments. However, owing to the high signal-to-noise ratio (S/N) of Fourier transform IR (FTIR), one can detect components having smaller frequency separations. This effective resolution... 

Fig. 3.4. In addition, if TG is implemented using SPC, a discriminator is required to separate the photon signal from background noise.

Radiation detector output signals are usually weak and require amplification before they can be used. In radiation detection circuits, the nature of the input pulse and discriminator determines the characteristics that the preamplifier and amplifier must have. Two stages of amplification are used in most detection circuits to increase the signal-to-noise ratio. 

---