op amp circuit

I require a Single Op-Amp Bandpass Filter circuit with a gain of 100X
and the frequency range is 0.1 Hz to 45 Hz.

I found a circuit in the following website:

http://ourworld.compuserve.com/homepages/Bill_Bowden/opamp.htm

According to specs, the Q factor must be greater than the square root
of half the gain. But as you can see my requirements do not meet with
this condition. Hence, please help me out here.

Thanks.

 

This circuit will do what you want,but requires a big capacitor on the
input. If you use a dual opamp like the NE5532 you need the same space but
can reduce the cap by a factor of 100 or more. The noise will go up tho.

||
.----||--.
| 3n3|| |
\] ___ | ___ |
o---|]--|___|--o--|___|-o
/]+ 11k | 1M1 |
150u | |\ |
'--|-\ |
| >--o---o
.--|+/
| |/ NE5534
___ | ___
GND-|___|-o-|___|-VCC
22k | 22k

 

This circuit will do what you want,but requires a big capacitor on the
input. If you use a dual opamp like the NE5532 you need the same space but
can reduce the cap by a factor of 100 or more. The noise will go up tho.

||
.----||--.
| 3n3|| |
\] ___ | ___ |
o---|]--|___|--o--|___|-o
/]+ 11k | 1M1 |
150u | |\ |
'--|-\ |
| >--o---o
.--|+/
| |/ NE5534
___ | ___
GND-|___|-o-|___|-VCC
22k | 22k

 

A frequency range of 450:1 is way too large for a simple
bandpass filter. You should have separate low-pass
and high-pass stages for this.

Best regards,


Bob Masta
dqatechATdaqartaDOTcom

D A Q A R T A
Data AcQuisition And Real-Time Analysis
www.daqarta.com
Home of DaqGen, the FREEWARE signal generator

 

I think you should think in terms of a dual opamp and a 10X high pass
filter (2 or 3 poles) followed by a 10X low pass filter (2 or 3 poles).

You might download a free copy of this little filter design aid to
play around with variations.

http://www-s.ti.com/sc/techzip/slvc003.zip

 

that page doesnt give the single op amp sallen key bandpass filter, wich u
might look at as an alternative, the one shown is a multiple feedback type.

try this calculator ....

http://www.analog.com/analog_root/static/techSupport/designTools/interactiveTools/filter/filter.html

Colin =^.^=