6.1.15 Excitation waveform
QuickWave allows the user to observe the time-waveform of the excitation signal. If there is more than one source, the waveform at each source is available. There are two options for excitation waveform observation discussed in the following subsections.
The Dynamic Waveform option available in the 1D Fields tab allows for watching the time-waveform of the excitation signal in the actual FDTD time. The waveform is displayed in 1D Fields window. We may say that we can watch on line the waveform that is actually generated by the software and enters the circuit.
As mentioned above, in this option the display of time-waveform is available in the actual FDTD time, thus in case of excitation signals with a finite duration time, to observe the entire waveform it is required to invoke the Dynamic Waveform option before the first FDTD iteration. Otherwise, if the option is invoked after several iterations, some part or entire waveform may already pass, depending on its duration (the duration of the excitation pulse expressed in FDTD iterations is given for every simulation in the Simulator Log window).
The Dynamic waveform option has many advantages but at the same time the time-waveform of the exciting signal is available only during its duration time (what is not an issue in case of sinusoidal signal). For that reason QuickWave enables also watching the entire (static) time-waveform at any simulation stage (after the excitation signal passes – starting from the Mth FDTD iteration, where M=N+1 and N is the exciting signal duration in FDTD iterations). In case of sinusoidal signal its time-waveform is available after one period (and shows only one period of the signal). This feature is available via Saved Waveforms command of Fields main menu, which loads the time-waveform of the exciting signal from file. The excitation time-waveform is saved automatically by the software after the signal duration ends (or after one period for sinusoidal signal). This option is not consuming in terms of computer resources but if the user wants to disable saving the time-waveform of the exciting signal, it can be done in Preferences dialogue in Processing tab. The time-waveform of exciting signal is saved to *.tpd file with a name following the rule:
projectname_Waveform_sourceportname_automatic.