Signal generator

A signal generator controls the signal emanating from an input line, when an NNetSimu model is running.

Parameters
A signal generator has a total of five parameters that describe its behaviour.
 * Parameters for the base signal
 * (1) Base frequency
 * (2) Base amplitude
 * Parameters for the stimulus signal
 * (3) Maximum frequency
 * (4) Maximum amplitude
 * (5) Time for maximum signal intensity

Generated signal
During normal operation, a signal generator generates a signal with base frequency and base amplitude. When a stimulus is triggered, the signal generator switches to the stimulus parameters. Starting from the base parameters (1) and (2), frequency and amplitude rise, until the maximum values (3) and (4) are reached. The parameter for maximal signal density (5) determines the time, when this peak is reached. After the peak, frequency and amplitude sink gradually, until they finally reach the base values again.

The ascent to the peak intensity of frequency and amplitude ist steep, the descent after the peak is rather flat (see picture). NNetSimu uses the function f(x) = ax * b(1-x) to model this behaviour.

Creating and selecting signal generators
A model can have several signal generators to model different behaviour of input lines. Every model has at least one signal generator, called "Standard". If necessary, the user can create additional signal generators with the "Create new" command in the submenu "Signal generator". New signal generators are initially named "SigGen 1", "SigGen 2" and so on. The signal designer has a command to change the name at the user's discretion. All user defined signal generators are listed in the "Signal generator" submenu between the entries "Standard" and "Create new".

Input lines
The purpose of signal generators is to supply input lines with artificially generated signals. Signal generators and input lines have a 1:n relation. One signal generator can be attached to several input lines, but every input line is attached to exactly one signal generator. Initially every input line is attached to the signal generator "Standard".

If additional signal generators have been created by the user, input lines can be attached to one of these signal generators:
 * Make sure that the desired signal generator is active (= visible in the signal designer). If not, use the submenu "Signal generators" in the main menu to select the desired signal generator.
 * To attach a single input line use the command "Attach active signal generator" in the context menu of the input line
 * To attach all input lines in an input connector use the command "Attach active signal generator" in the context menu of the input connector

Editing a signal generator
The tool to visualize and manipulate a signal generator is the signal designer.