diff --git a/ANALYSES b/ANALYSES index 0a5411ea4..7992cd3ab 100644 --- a/ANALYSES +++ b/ANALYSES @@ -1,24 +1,101 @@ +12345678901234567890123456789012345678901234567890123456789012345678901234567890 + ANALYSES ------------------------------------------------------------------ +======== This file lists the analyses currently implemented into ngspice. -AC : Small-signal frequency response analysis +Table of Contents + + 1 Noise analysis (NOISE) + 2 Operating point analysis (OP) + 3 Operating point sweep Analysis (DC) + 3.1 Enhancements + 4 Pole-zero analysis (PZ) + 5 Small-Signal distortion analysis (DISTO) + 6 Small Signal frequency response analysis (AC) + 7 Sensitivity analysis (SENS) + 8 Transfer function analysis (TF) + 9 Transient analysis (TRAN) + + + +1 Noise analysis (NOISE) + + The noise analysis does analysis device-generated noise for the given + circuit. When provided with an input source and an output port, the analysis + calculates the noise contributions of each device (and each noise generator + within the device) to the output port voltage. It also calculates the input + noise to the circuit, equivalent to the output noise referred to the + specified input source. This is done for every frequency point in a specified + range - the calculated value of the noise corresponds to the spectral density + of the circuit variable viewed as a stationary gaussian stochastic process. + + +2 Operating point analysis (OP) + + The operating point analysis determines the dc operating point of the + circuit with inductors shorted and capacitors opened. + + +3 Operating point sweep Analysis (DC) + + The operating point sweep analysis determines the values of output + variables while one or two specified independent voltage or current source is + stepped over a user-specified range and the dc output variables are stored + for each sequential source value. + + 3.1 Enhancements + + Added resistance and temperature sweep. + + +4 Pole-zero analysis (PZ) + + The pole-zero analysis computes the poles and/or zeros in the small-signal + ac transfer function. The program first computes the dc operating point and + then determines the linearized, small-signal models for all the nonlinear + devices in the circuit. This circuit is then used to find the poles and zeros + of the transfer function. + + +5 Small-Signal distortion analysis (DISTO) + + The distortion analysis computes steady-state harmonic and intermodulation + products for small input signal magnitudes. Not all devices are supported. + + +6 Small Signal frequency response analysis (AC) + + The ac small-signal computes the ac output variables as a function of + frequency. The program first computes the dc operating point of the circuit + and determines linearized, small-signal models for all of the nonlinear + devices in the circuit. The resultant linear circuit is then analyzed over a + user-specified range of frequencies. + + +7 Sensitivity analysis (SENS) + + Ngspice will calculate either the DC operating-point sensitivity or the AC + small-signal sensitivity of an output variable with respect to all circuit + variables, including model parameters. Spice calculates the difference in an + output variable (either a node voltage or a branch current) by perturbing + each parameter of each device independently. -DC : DC-sweep analysis - + Added resistance sweep as in spice 2. - * Note: It is possible to perform a generic parametric sweep ? -DISTO : Small signal distortion analysis +8 Transfer function analysis (TF) -NOISE : Noise analysis + The (small signal) transfer function analysis computes the dc small-signal + value of a transfer function (ratio of output variable to input source), + input resistance, and output resistance is also computed as a part of the dc + solution. -OP : Operating point analysis -PZ : Pole-Zero analysis +9 Transient analysis (TRAN) -SENS : Sensitivity analysis + The transient analysis computes the transient output variables as a + function of time over a user-specified time interval. The initial conditions + are automatically determined by a dc analysis. All sources which are not time + dependent (for example, power supplies) are set to their dc value. -TF : Transfer function analysis -TRAN : Transient analysis