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Setup question for signal source and buffer - RF Cafe Forums
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Post subject: Setup question for signal source and buffer
Posted: Fri Oct 27, 2006 11:10 am
Fri Apr 07, 2006 6:10 pm
I need your practical opinion
from experience, if any. I have a signal source. Part of this signal
needs to be sampled. One sampling process involves detecting whether
the signal is there or not. Another sampling process will try to detect
whether the signal amplitude has surpassed a certain threshold.
Just assume that the signal is a low frequency signal at 38 kHz.
Would it be optimal to do the following setup?
- use a quad
opamp package and configure three of the opamps as voltage buffers /
- tie the input of the three opamps to the same node
- connect the signal source to this common node
The first opamp
would just replicate the signal source and send it unprocessed. The
2nd and 3rd opamp would do the sampling processing schemes.
this sound right?
Or would it be ok to skip the buffer setup
and directly interface the signal source to a common bus that branches
off directly to the sampling sections? This is assuming that the two
sampling schemes utilize op amp inputs to do the signal detection and
peak detection. Thanks!
Posted: Fri Oct 27, 2006 11:22 am
Fri Feb 17, 2006 12:07 pm
Location: London UK
such a low frequency, I would have the first OA as a voltage follower/buffer.
The output would go to the second stage as a full-wave detector with
a time constant well in excess of the carrier cycle time (ie LPF).
The output would split two ways.
One way to a Schnitt Trigger to
act as the "Signal/NOT signal" output, with the trigger level set just
above noise (assuming this level is predictable).
The second way
would be to another Schmitt Trigger with an adjustable trigger threshold
set to whatever level you are looking for.
If only we had a simple