To add power spectrum filtering capability to a transmitter or receiver, go to the Filter tab on the Basic Definition page for the Receiver or Transmitter and select Use under Filter Model.
To add this capability to a Radar, go to the RF Filter tab on the Basic Definition page for the Radar and select Use.
STK provides the following filter models:
- Bessel
- Butterworth
- Chebyshev
- Cosine Window
- Elliptic
- External
- FIR
- FIR Box Car
- Gaussian Window
- Hamming Window
- IIR
- RC Low-Pass
- Raised Cosine
- Rectangular
- Root Raised Cosine
- Script
- Sinc
- Sinc Envelope Sinc
A spectrum filter can be used to accurately model the power transfer from a transmitter to a receiver or a jammer to a receiver. This can be handy when trying to model adjacent band interference or for evaluating link performance for a given specific power spectrum mask.
Adding a spectrum filter to a transmitter will shape the output spectrum by multiplying the signal PSD by the selected filter’s frequency response. Adding a filter to a receiver will shape the received PSD by multiplying it by the selected receiver filter’s frequency response.
When performing a link budget between two objects either of which (or both) contains a filter, the bandwidth overlap factor is computed by integrating the composite PSD (received PSD multiplied by the receiver filter’s frequency response), over the receiver’s bandwidth, and dividing by the total power in the original signal PSD.