HPF_RaisedCos (Highpass Filter, RaisedCosine)
Symbol
Available in ADS and RFDE
Parameters
Name 
Description 
Units 
Default 

Alpha 
Rolloff factor defining filter excess bandwidth, 0 ≤ Alpha ≤ 1 
None 
0.35 
SymbolRate 
Digital symbol rate defining filter bandwidth 
kHz 
24.3 
DelaySymbols 
Number of symbols delayed by filter 
None 
5 
Exponent 
Exponent factor ( 0 ≤ Exponent ≤ 1 ), to provide for Root RaisedCosine filter 
None 
0.5 
DutyCycle 
Pulse duty cycle in percent, used for sinc(x) correction 
None 
0 
SincE 
Flag to include the Exponent factor on the sinc(x) correction: yes or no 
None 
no 
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 
Other 
Output string to netlist 
None 
None 
Range of Usage
0 ≤ Alpha ≤ 1
DelaySymbols ≥ 1
0 ≤ Exponent ≤ 1
0 ≤ DutyCycle ≤ 100
Notes/Equations
 Refer to Filter Categories.
 This filter is unidirectional; input impedance is infinite; output impedance is specified by Zout.
 This filter is unidirectional; input impedance is infinite; output impedance is specified by Zout.
 Voltage gain is described by the following function.
where:G_{filt}
= 0.0 for frequency ≤ 0.5 × (1 − Alpha ) × SymbolRate
= 1.0 for frequency ≥ 0.5 × (1 + Alpha ) × SymbolRate
= [0.5 × (1 + sin[π × ( frequency − SymbolRate /2)/
G_{comp}
= 1.0
if DutyCycle =0
= [0.01 × DutyCycle × sinc(x)]^{Exponent}
if SincE = YES
= [0.01 × DutyCycle × sinc(x)]
if SincE = NO
sinc(x)
= sin(x)/x
x
= 0.01 × DutyCycle × π × frequency / SymbolRate
 While Exponent can be any value, the standard value is 1.0 for the ideal raisedcosine filter response or 0.5 to simulate the root raisedcosine filter response when present at both the receiving and transmitting channels.
 In steadystate frequencydomain analyses, the ideal frequencydomain response described previously is used; however, this ideal response has an infinite duration impulse response that must be approximated for timedomain simulations in either Transient or Circuit Envelope. If DelaySymbols is set too small, then the impulse response will be severely truncated and will not accurately reflect the ideal frequency response.
Using a Hanning window (WindowType=1) a DelaySymbols value of 15 should result in equivalent frequency domain sidelobes of −90dBc or smaller.  Accuracy of this model in Transient or Circuit Envelope can be further controlled through the ImpMaxFreq, ImpDeltaFreq, and ImpMaxPts parameters.
 The filter can include gain equalization to compensate for duty cycle rolloff. If DutyCycle = 0.0, then no compensation will be applied. If SincE=YES, Exponent will be applied to the gain compensation term, G_{comp}. The Exponent term is always present in the G_{filt} term.
 This component has no default artwork associated with it.