alok_ky
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what is knee frequency
I happen to come across trwo terms :
1. knee frequency (=0.5/rise_time)
2. 3-dB Frequency (0.35/rise_time)
What is the difference between the two ?
If we see the definitions of the "A Handbook of Black Magic" by Howard Johnson, we can see from the figures there, with the definitions, that knee frequency is shown ~45dB below the peak. and 3dB frequency ast -3dB below.
If the frequency response falls at the rate of -20dB/decade, then the knee frequency should be approx.2 decades away from the 3-db frequency.
But the above formulas show only as difference of 05/0.35
Why is it so ?
-sanjeev
I happen to come across trwo terms :
1. knee frequency (=0.5/rise_time)
2. 3-dB Frequency (0.35/rise_time)
What is the difference between the two ?
If we see the definitions of the "A Handbook of Black Magic" by Howard Johnson, we can see from the figures there, with the definitions, that knee frequency is shown ~45dB below the peak. and 3dB frequency ast -3dB below.
If the frequency response falls at the rate of -20dB/decade, then the knee frequency should be approx.2 decades away from the 3-db frequency.
But the above formulas show only as difference of 05/0.35
Why is it so ?
-sanjeev