Adding Noise to a Voltage Source in HyperLynx AMS

When simulating electrical circuits in HyperLynx AMS, you may want to add noise to a voltage source to study its impact on circuit behavior. This can be easily achieved using the function generator models available in PartQuest Explore. These models allow for time-domain noise generation with customizable parameters, providing flexibility for a variety of simulation needs.

Using PartQuest Explore's Function Generator Models

The function generator source models in PartQuest Explore are designed to generate time-domain noise. These models also support other waveforms such as DC, Sine, Pulse, Ramp, and Piecewise Linear (PWL). To add noise to a voltage source, follow these steps:

1. Specify Noise Parameters:
   • DC Offset (vn_dc): Sets the constant voltage level around which noise is added.
   • RMS Value of Noise Voltage (vn_ac_rms): Defines the amplitude of the noise.
   • Noise Bandwidth (noise_bw): Specifies the frequency range of the noise.
2. Select the Noise Function:
   • Use the radio-button selector in the PartQuest Explore symbol to select the desired function type (e.g., Noise). This interface simplifies the process by showing only the parameters relevant to the selected function.

Using Noise in HyperLynx AMS

If you are working directly in HyperLynx AMS and do not have access to the PartQuest Explore user interface, you can use the VHDL-AMS text from the function generator model. Here's how:

1. Copy and Paste the Model Code:
   • Import the VHDL-AMS code for the voltage function generator model into your design.
2. Set the select_function Parameter:
   • To use the noise function, set the select_function generic parameter to the value 6.
3. Configure the Noise Properties:
   Define the following parameters:
   • vn_dc: DC offset voltage.
   • vn_ac_rms: Root mean square value of the noise voltage.
   • noise_bw: Bandwidth of the noise signal.

Additional Tips

• If you only need a stand-alone time-domain noise source (without the other waveform functions), you can request a simplified version of the function generator model. This version focuses exclusively on noise generation and is easier to use, although less flexible than the full function generator model.

• For users of Xpedition AMS, remember that you will not have the radio-button selector interface. Instead, you will need to manually set the function type and parameters through the VHDL-AMS code.

By following these steps, you can efficiently add noise to a voltage source and customize its properties to suit your simulation requirements. Whether using the full function generator model or a dedicated noise source, HyperLynx AMS provides powerful tools for analyzing noise effects in your designs.