QSPICE - Learn how to use QSpice from the beginning

# Start to use Qspice textbook circuit models from ASICedu.com - Make sure to install QSPICE and unzip the Qspice_CMOSedu.zip (link) - Launch QSPICE - Open a schematic using the 'open' icon in the toolbar - Navigate to the Qspice model folder extracted from Qspice_CMOSedu.zip - Select a schematic corresponding to a book figure - Run the simulation by clicking the 'Green' icon in the toolbar menu - The simulation results will automatically plot in another Qspice window - To display some other signals, voltage or current: 1. make sure the '.save all' spice code is used in the schematic; 2. Right click the plot panel and select 'Add Window' to create a new panel; 3. Right click the new panel and select 'Add Plot' in the new panel; 4. Pick the voltage or current you like to plot and then click 'OK'. (On the top of 'Compose Expression to Plot', many math functions can be used) --- > Launch QSPICE --- > Open a new QSPICE schematic --- > Select the textbook circuit model --- > Run the simulation --- > Plot simulation results and Create a new window panel in the plot (Right click the current plot panel)  --- > Add plot in the new panel (Right click the new panel)  --- > Select another signal to plot in new panel and function table listed in the 'New Expression window'  --- > Final Simulation Result Plot 

Matlab - Add reference line in a bode plot

# Add reference line in a bode plot Sometimes, adding a reference line can explain a lot in a plot. For PLL noise transfer functions, the reference noise transfer function has a low pass characteristic. The VCO noise transfer function has a high pass characteristic. The PLL bandwidth splits the noise plot into two regions: - phase noise of VCO dominates the high frequencies because its noise transfer function have no effect in this region - phase noise of references and phase detector dominates the low frequency region > noise transfer functions of the reference and VCO Therefore, it is useful to show the PLL bandwidth in the plot. New version Matlab provides a 'xline' function, vertical line with constant x-value, to plot a line in a plot. If you don't have the new version of Matlab, you can use another m function ([Link](https://wwem.lanzouq.com/iSonk1hpecmh)) to add a reference line. Example code is shown below: