Page 308 - Analog and Digital Filter Design

Filter Design Software

is in series or parallel (shunt) with the resistive load, enter the word “series” or
“shunt” to select your choice; let’s say “shunt.” The value of the reactive com-
ponent must now be entered, for example 1 x IO-’’ (which equals lOOpF).

With all the design parameters entered, the program tries to design a suitable
matching network. The network may be an L, T, or PI section. The L section is
tried first, and if successful the component values are displayed. If no match-
ing network can be found using the L section, the second attempt tries to find
a network using a T section, and if unsuccessful the third attempt tries a PI
section. If all types of matching network are tried but fail to achieve the required
VSWR performance, the program will output a message saying that the design
is not possible.

If the component values used as examples in the text are input (50-ohm source,
100-ohm load, matching between 1 MHz and 2 MHz with a VSWR of less than
2 and a load resistor having a l00pF capacitor in parallel), the result is a series
inductor of 5.305165pH followed by a shunt capacitor of 961 pF.

References

1. FILTECH, Number One Systems, Oak Lane, Breden, Tewkesbury,
Glos., www.numberone. corn. Tel. (01 684) 77 3662.
7 Super FILTER, www.superfilter.com.
-.
2 Filter Master Active, www.1ntusoft .corn.
d.
4. Filter Master, www.Intusoft.com.
5. ELSIE, www,arraysolutions.com.
6. Signal Processing Worksystem, mvwcadence.com.
7. AFDPLUS, Webb Laboratories, Wisconsin, U.S.A.,
www. i-efi-eq. comiu.ebsitesin~ebblabs. hi. Tel. (414) 367-6895.
8. PC Filter, M. G. Ellis, Artech House (publishers).
9. FilterProT”, TI (semiconductors), www.ti.com.
IO Filter Solutions@, Nuhertz Technologies, il.~ti~i:Jilter.-solutions. coin. Tel.
(602j 216-2682.