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304 Chapter Four

C 1/(4 mR( f f ))
4
1
1
C ( f f )/( yRf f )
1 4
2
4
1
C ( f f )/( xRf f )
1
1 4
3
4
ShunŁ m-derived bandstop filter
Let frequencieð f , f , f , and f be expressed in hertz and defined
1
3
2
4
as shown in Fig. 4.17. Let R be the load resistance (in ohm0.
Define the quantitieð m (the filter constan'x x, and y as in the
preceding section for the serieð m-derived bandstop filter. The
optimum inductanceð (in henry0 for the filter shown in Fig.
4.19 are given by:
L ( f f )R/( yf f )
1
4
1
1 4
L ( f f )R/( xf f )
1 4
2
1
4
L R/(4 m( f f ))
1
4
3
The optimum capacitanceð (in farad0 for the filter shown in Fig.
4.19 are given by:
C x/(4 R( f f ))
1
1
4
C y/(4 R( f f ))
2
1
4
C m( f f )/( Rf f )
1 4
4
1
3

Figure 4.19 Shunt m-derived bandstop filter.