Hello Jerry,
The opamp's output was in the saturated region instead of the
linear region. I tried his example with the additional negative
supply voltage and discovered that the opamps oscillate.
I have then used the 4 digit values for all the resistors as
shown in the datasheet. Now it seems to be OK.
Files > Temp > bandpass1750.asc
Best regards,
Helmut
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--- In LTspice@..., Jerry Lee Marcel <jerryleemarcel@...> wrote:
You must run an AC analysys to see the frequency response.
Your settings for transient analysis must be wrong - showing huge spikes
at the output.
Le 02/08/2013 11:08, resetpin a ¨¦crit :
Hi,
I uploaded the files into files/temp folder.
hope someone can give me a hint
Thanks in advance
Resetpin
--- In LTspice@... <mailto:LTspice%40yahoogroups.com>,
"resetpin" <resetpin@> wrote:
Hello,
I used Filter Pro from Texas instruments to get a Filter design from
my specifications. They are:
Gain: 5V/V (13,97dB)
Part: Ideal Opamp: Order 4 Stages: 2
Corner frequency Attenuation: 10,979dB
Allowable PassBand Ripple 1dB
Center Frequency: 1,75 kHz
Stopband Attenuation: -30dB
Passband Bandwidth: 100Hz
Stopband Bandwith: 600Hz
Filterpro proviced a schematic and Values for the parts and a
Gain-Frequency plot.
When I try to redo this in LTSpice the frequency corner freqency of
the filter is at the right positon but the gain is about -40db.
I wonder where the differences are and would like to show the
LTSpice *.asc File compared with the Texax Results but don't know how
to post them here in the group.
Maybe someone is willing to help me out and show me the differences
or the problem.
Thanks in advance
Resetpin
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