CW narrow filters
RHF wrote:
On May 6, 10:38 pm, Telamon
M... Sushi,
Should not the Two separate IF Filters of the same Band-Width : one
for the 1st IF and one for the 2nd IF create a Series RF Signal
Path resulting in a better combined Filtering Shape Factor then one
along; plus improve the Ultimate Rejection of the RF Signal Path.
Shape Factor : 2.0 & 2.0 = 1.4
Ultimate Rejection : 60 dB & 60 dB = 90 dB
SNIP
- That's some very interesting math you got going there.
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- Telamon
- Ventura, California
Telamon - Did I say it was "Math" ?
Shape Factor : 2.0 (1st IF) and 2.0 (2nd IF) comes out
to roughly 1.4 at the end of the IF Processing Stages
in the Signal Path.
OK so 60 dB was a bad number so make it 85 dB.
Ultimate Rejection : 85 dB (1st IF) and 85 dB (2nd IF)
comes out to roughly 127 dB at the end of the IF
Processing Stages in the Signal Path.
practically speaking - no math required ~ RHF
.
RHF,
As far as I know there is no general method that allows you to combine
shape factors for two filters into a number describing the net result.
I also know of no general method for combining rejection of two filters
to give a meaningful net number.
So, please tell us how you arrive at these numbers.
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