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High freq. signals are not simulating correctly
Whenever you are attempting to simulate high frequency signals (for example a 100Hz or faster oscillator), it is important that you adjust the simulation's timing settings to maintain simulation accuracy.
Users need to tailor the simulation parameters to their own particular circuits. Changes to timing settings are required because PCs are often not able to keep up with the high frequency signal in real time resulting in eratic simulations or strange outputs on a graph.
Please note that all circuits must be correctly grounded (or earthed) before they can be accurately simulated. A circuit that is not properly grounded may still produce unexpected results.
Understanding simulation time
The speed at which a circuit simulates is determined by something called simulation time.
Normally, simulation time is set to correspond to real time, whereby one second of simulation time takes one second to simulate. By slowing down simulation time, however, you can investigate circuits that normally operate too fast to be seen. Slowing down the simulation will also allow you to generate more accurate results by simulating more time points.
Adjusting a simulation's timing
You can slow down the simulation so that the high frequency signal can simulated more accurately. This is done via Timing Control:
To change the timing settings in Circuit Wizard, select Timing Control... from the Project | Simulation menu.
To change the timing settings in Livewire, select Timing Control... from the Tools | Simulation menu.
In the window that appears, the Time Base setting controls simulation time. It defines how much simulation time takes place in one second. For real time operation, set the time base to 1 second.
Setting the time base to 500ms will mean that the circuit simulates at half the speed, so it would take two seconds to simulate one second of your circuit.
You should experiment with the Time Base setting, using the examples below as a starting point:
  For a signal of 100Hz, try a Time Base setting of 50ms.
  For a signal of 1kHz, try a Time Base setting of 5ms.
  For a signal of 10kHz, try a Time Base setting of 500us.
  For a signal of 100kHz, try a Time Base setting of 50us.
For more information on this topic, click on the Help button in the Timing Control window.
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