A general equation revealing the relationship between the attenuation at passband center A （ 0 ） and the parasitic dissipation factor of the elements o and input dissipation factor d is derived for all-pole type lossy filter. Based upon this equation

families of curves are computed and plotted for three conventional types of filters. For filters with given element dissipation factor

both the optimum selection of the input dissipation factor and the determination of the attenuation at the passband center can be readily accomplished with the aid of these curves. If the allowable range of the attenuation at the passband center is given

the same families of curves enable us to determine conveniently the corresponding allowable range of the element dissipation factor.Some problems of practical interest are also discussed in connection with examples.