Small-signal analysis

For a BJT, the Bias Point Detail gives the collector current, the collector-emitter voltage, and some small-signal parameters for the BJT at the bias point. For a jFET, the Bias Point Detail gives the drain current, the drain-source voltage, and some small-signal model parameters at the bias point. The results of the Bias Point Detail are contained in the output file. We will illustrate the Bias Point Detail analysis with the circuit below ... 

DC Operating Point Analysis DC Small-Signal Transfer Function DC Sweep Analysis Sensitivity Analysis AC Analysis... 

SPICE tip SPICE automatically precedes the AC and transient analyses with two operating point analysis, one for AC and one for the transient. The operating point values are used to set the biasing for the AC analysis and the initial starting point for the transient analysis. For the AC analysis the operating point analysis is often called the small signal bias solution. 

The maximum of the semicircle appears at wmax = kiec + k . It follows that frequency response analysis of the small signal photopotential response should give access not only to klr and krec but also to Csc and CH. The possibilities offered by intensity modulated photopotential measurements remain largely unexplored, although Kamieniecki used the method... 

After this step the Cu(II) signal, which shows the presence of Cu(II) in two different magnetic environments, decays slowly to a residual small signal typical of the native enzyme. The best analysis of the spectrum shows that one type of Cu(II) signal, Cui, decays within minutes, ti/o = 5 min. The second type, Cu2, decays more slowly with ti/2 = 2% to 3 hr. Activity is restored to the apoenzyme by a first-order process with a half-time corresponding to that of the slowly disappearing Cu(II) signal (116). Thus reconstitution of the active protein from Cu(II) and the apoenzyme is a complex, slow process which involves... 

Precise analysis of the H NMR spectrum of PA showed the presence of small signals corresponding to 8 -HOABA at an intensity of 1-2% of those of PA, confirming that a methanol solution of PA is actually a tautomeric mixture of PA and a trace amount of 8 -HOABA. Careful... 

Remember 14.2 The small-signal transfer function may be analyzed at different values of the static property space, which represents a linearized characterization of the system. The same information is obtained as would be obtained by analyzing the entire nonlinear electrochemical system using a large-amplitude perturbation technique such as cyclic voltammetry, but the analysis is simpler. 

Note Under very large fine or foad steps, we wilf actually no longer be operating in the domain of the small-signal analysis which we have been performing so far. In that case, the initial overshoot/undershoot at the output is almost completely determined simply by how large a bulk capacitance we have placed at the output. That capacitance is needed to hold the output steady, until the control loop can enter the picture and help stabilize the output. 

A simple one-dimensional spectrum is always recorded at the start of any structural analysis. Small modifications to the ID pulse sequence enables the selection of groups of signals or singlet signals, the separation of multiplets for determining coupling constants or multiplicity and the determination of molecular parameters such as relaxation times or diffusion constant. In addition ID pulse sequence can also be converted into 2D sequences (and vice versa) enabling homonuclear and heteronuclear correlation. Table... 

A valve may usually be modelled as an exponential lag, subject to rate limits. For small-signal, linear analysis, the rate limits will not be breached, so the model is simply ... 

Electrochemical small signal AC-analy-sis that yields capacities C, resistances R or conductivities, detection of space charges, and other electronic properties. Large signal analysis by DC pulses yields kinetic information under insta-tionary conditions. 

---