Full gain narrowing

A high proportional gain is equivalent to a narrow PB, and a low gain is wide PB. We can interpret PB as the range over which the error must change to drive the controller output over its full range.1... 

When operated as a specific detector the ion-trap detector is more sensitive still but not to the extent that would be expected from the performance of other mass spectrometers operated in this mode in view of the large number of ions monitored in full scan mode there is little more sensitivity to be gained by spending a little extra time scanning a narrow mass range, and the detection limit in this mode is in the region of l-2pg. 

Narrow and broad MW standards were injected onto the HPSEC-DV system at concentrations near 1 mg/mL and 2 mg/mL, respectively. Initially, in order to obtain a usable differential pressure chromatogram, the lignin samples were injected at concentrations near 20 mg/mL, with an instrument (A-D amplifier) gain setting of 1 (0-1.0 volt Full Scale). As the... 

Fig. 26. Experimental ( H)- C cross-polarization spectra of an aqueous dispersion of poly-n-butylcyanoacrylate nanocapsules at different mixing periods tc. The spectra are measured at a resonance frequency of Wc 100 MHz after contact times of cp O.l, 0.25 and 0.5 ms under full proton decoupling. The wide lines derive from the polymer forming the capsule membrane while the narrow lines are assigned to the triglyceride oil. At cp = 0.25 ms, the broad signals of the polymer have almost developed to their full intensity, whereas the signals of the oil still gain amplitude. ...

If we take the Bode plot of any current mode controlled converter (one that has not yet entered this wide-narrow-wide-narrow state), we will discover an unexplained peaking in the gain plot, at exactly half the switching frequency. This is the source of subharmonic instability. Because, though this point is much past the crossover frequency, it is potentially dangerous because of the fact that if it peaks too much, it can end up intersecting the 0 dB axis again — which we know is one of the prescriptions for full instability. 

An extremely sensitive MODR scheme, microwave optical polarization spectroscopy (MOPS), was introduced by Ernst and Torring (1982). The most important features of MOPS are that it requires respectively 100 and 10 times lower laser and microwave intensities than MODR and results in 10 times narrower lines. This means that it will be possible to take full advantage of differential power broadening effects (Section 6.5.1) and to utilize low-power, frequency-doubled dye lasers and low-power, broadly tunable microwave sources (backward wave oscillators) in order to gain access to and systematically study perturbations. 

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