# SLiCAP tutorials¶

The following tutorials are available:

## Basic SLiCAP tutorial¶

All other tutorials assume the topics from this one as known. These topics are:

2. Configure LTspice as schematic capture tool for SLiCAP
3. Display circuit information on a web page
4. Obtain the MNA matrix equation of a network and display it on a web page
5. Calculate the transfer of a network symbolically and display it on a web page
6. Make (Cartesian) frequency-domain plots and display them on a web page
7. Calculate (numeric) the DC value and the poles and zeros of the transfer and display them on a web page
8. Calculate and plot the unit-impulse response and display them on a web page
9. Calculate and plot the unit-step response and display them on a web page
10. Set-up and solve design equations of a network

### Exercise¶

Theory: “Structured Electronic Design” ISBN 97890-6562-4277. Chapter 18: Network Theory (selected topics).

The figure below shows a photo of an oscilloscope probe and an equivalent network of such a probe.

The capacitor C2 models the cable capacitance $C_c=80pF$. The resistance $R_{se}$ of R1, together with the input resistance of the oscilloscope defines the attenuation of the probe. The compensation capacitor C1 with a capacitance $C_{cmp}$ should be tuned such that the high-frequency attenuation equals the DC attenuation.

The probe should have an attenuation factor of 10 when it is used with oscilloscopes with an input resistance of $1M\Omega$ and an input capacitance between $15pF$ and $50pF$. The probe will be calibrated with the aid of a voltage source with a source resistance of $50\Omega$ that provides a square wave calibration voltage with a period of $1ms$.

1. Design the value of $R_{se}$ and the tuning range of $C_{cmp}$.
2. Check your result with SLiCAP:
1. Draw schematic of the probe connected to the calibration source and the oscilloscope; use LT spice and SLiCAP symbols. If you want to set the resistance of the calibration source to zero, use the symbol ‘SLR_r’ for it.
2. How many poles and zeros does the transfer of the calibration circuit have? Motivate your answer!
3. How many poles and zeros does the transfer of the calibration circuit have in the case in which the resistance of the calibration source equals zero? Motivate your answer!
4. Create a SLiCAP project
5. Create s script file with instructions that:
1. Print the circuit data on a web page
2. Determine the transfer function and display it symbolically on a web page
3. Design the components for proper operation
4. Estimate the location of the pole(s) and the zero(s)
5. Print the DC gain and the poles and the zeros of the gain on a web page
6. Plot the unit step response and display it on a web page
7. Plot the magnitude and the phase characteristic and display it on a web page
8. What is the -3dB bandwidth of the complete calibration system?

## Parameter tutorial¶

The tutorial parameters teaches the use of parameters:

1. Symbolic versus numeric simulation
2. Create a circuit with parameters: a current-driven, capacitively loaded CE-stage
3. Change and obtain parameter definitions from/in the MATLAB environment
4. Stepping of parameters
5. Plotting of parameters against each other
6. Stepped execution of instructions
7. Plotting of stepped execution results

### Exercise¶

Continuation of the exercise of the previous tutorial.

Assume an oscilloscope with an input capacitance of $25pF$.

1. Plot the pole positions as a function of the compensation capacitance.
2. Plot the magnitude and phase characteristic of the calibrated probe and for the maximum and minimum value of the compensation capacitance.
3. The influence of a finite area of the current loop formed by the probe tip and the ground lead can be modeled with the aid of an inductance in series with the loop. If the ground clip is not connected, this inductance may limit the bandwidth of the probe.
1. Study the influence of this ground loop by placing an inductance in series with probe tip with a value between $10nH$ and $100nH$.
2. Use a root-locus plot, a step response and magnitude and phase characteristics.

## Filter design tutorial¶

The tutorial Design of a passive low-pass Linkwitz-Riley filter teaches the design of a filter with the aid of a prototype transfer function and a target circuit:

1. Circuit for a 4-th order low-pass passive LRC filter
2. Prototype transfer of a 4-th order low-pass Linkwitz-Riley filter
3. Determination of the filter component values
4. Plotting of the characteristics of the ideal filter
5. Selection of practical components
6. Circuit including inductor losses
7. Plotting of ideal AND nonideal filter characteristics on the same axis