Title: what's wrong with this code? (active filter PSpice
Post by Katerina on Apr 29th, 2005, 5:16pm
i am trying to design this bandpass filter [output V(6)] with fo=1kHz and BW=100Hz.
I am sure that my design is corect but Pspice doesn't agree and gives me bandwidth of 500Hz
Is there something wrong with my code?
please help
I use the following equation sto calculate R4,R5,R1,R2:
fo=1/pi RC where R=R4=R5 and C=C1=C2
Q=R2/R
they are standard for the Biquad filters
Code:
*Amplifier AC Input Voltage
*DC Voltage Source
Vcc 7 0 DC +15V
Vee 4 0 DC -15V
*Plot Command (Specified Frequency Range To Be Investigated)
Vin 1 0 AC 1V
.AC DEC 1 1HZ 3000000HZ
*****CIRCUIT****************************
R1 1 2 159k
R2 2 6 159k
R3 22 26 100K
R10 16 22 100K
R4 6 12 15.9k
R5 2 26 15.9k
C1 2 6 10nF
C2 12 16 10nF
X1 0 2 7 4 6 UA741
X2 0 12 7 4 16 UA741
X3 0 22 7 4 26 UA741
*-----------------------------------------------------------------------------
* connections: non-inverting input
* | inverting input
* | | positive power supply
* | | | negative power supply
* | | | | output
* | | | | |
.subckt uA741 1 2 3 4 5
*
c1 11 12 8.661E-12
c2 6 7 30.00E-12
dc 5 53 dy
de 54 5 dy
dlp 90 91 dx
dln 92 90 dx
dp 4 3 dx
egnd 99 0 poly(2),(3,0),(4,0) 0 .5 .5
fb 7 99 poly(5) vb vc ve vlp vln 0 10.61E6 -1E3 1E3 10E6 -10E6
ga 6 0 11 12 188.5E-6
gcm 0 6 10 99 5.961E-9
iee 10 4 dc 15.16E-6
hlim 90 0 vlim 1K
q1 11 2 13 qx
q2 12 1 14 qx
r2 6 9 100.0E3
rc1 3 11 5.305E3
rc2 3 12 5.305E3
re1 13 10 1.836E3
re2 14 10 1.836E3
ree 10 99 13.19E6
ro1 8 5 50
ro2 7 99 100
rp 3 4 18.16E3
vb 9 0 dc 0
vc 3 53 dc 1
ve 54 4 dc 1
vlim 7 8 dc 0
vlp 91 0 dc 40
vln 0 92 dc 40
.model dx D(Is=800.0E-18 Rs=1)
.model dy D(Is=800.00E-18 Rs=1m Cjo=10p)
.model qx NPN(Is=800.0E-18 Bf=93.75)
.ends
.OP
.PROBE
.END |
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http://briefcase.pathfinder.gr/download/elbereth_gr/25716/419359/0/active+filter.jpg
http://briefcase.pathfinder.gr/zoom/elbereth_gr/25716/419359
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