LPF_GMSK (Lowpass Filter, GMSK)
Symbol
Available in ADS and RFDE
Parameters
Name |
Description |
Units |
Default |
|---|---|---|---|
BT |
Bandwidth-Time Product of Gaussian Filter |
None |
0.3 |
BitRate |
Digital bit rate defining filter bandwidth |
kHz |
270.833 |
DelayBits |
Number of bits delayed by filter |
None |
5 |
Gain |
Gain factor |
None |
1.0 |
Zout |
Output impedance |
Ohm |
50 |
WindowType |
Window type applied to impulse response: 0=None, 1=Hann, 2=Hamming |
None |
0 |
ImpMaxFreq |
Maximum frequency to consider when calculating impulse response |
|
|
ImpDeltaFreq |
Frequency sample spacing when calculating impulse response |
|
|
ImpMaxPts |
Maximum number of points in impulse response |
None |
None |
Range of Usage
0 ≤ Alpha ≤ 1
DelayBits ≥ 1
Notes/Equations/Reference
- Refer to Filter Categories.
- For information on lowpass filter behavior at DC, refer to Lowpass Filter Behavior at DC.
- This filter is unidirectional. Its input impedance is infinite and its output impedance is specified by Zout.
- This Gaussian filter is used in the GMSK modulation system.
- In the steady-state frequency domain analysis, an ideal frequency-domain response is used. However, this ideal response has an infinite duration impulse response that must be approximated for time domain simulations in either Transient or Circuit Envelope. If DelayBits is set too small, then the impulse response will be severely truncated and will not accurately reflect the ideal frequency response.
- A value of 1.0 will be used internally when DelayBits is set to a value that is less than 1.0.
- Accuracy of this model in Transient or Circuit Envelope can be further controlled through the ImpMaxFreq, ImpDeltaFreq, and ImpMaxPts parameters.
- This component has no default artwork associated with it.