Hi all,
I have some questions to answer for my HNC homework, but am having a little trouble understanding the example we were given. I have top draw out some asymptotic bode diagrams.

In the example given the bode diagram was derived from the following formula:
Vo / Vin (jω) = 3 / (1+j3ω)(1+j4ω)

I know that the break points are at 0.25 and 0.33 as these can be found by inverting the constants 3 and 4, but I am not sure how to find the start point, which in this case is 9.5dB.

Any help would be much appreciated.
Mark

 

The formula you need to apply is:

\(Gain_{(dB)}\large\ =\ 20*log_{10}(3)\)

The 3 used above is the voltage gain taken from the transfer function.

hgmjr

 

Thats great. That should get me started. Thanks for your help.
MM

 

The formula you need to apply is:

\(Gain_{(dB)}\large\ =\ 20*log_{10}(3)\)

The 3 used above is the voltage gain taken from the transfer function.

hgmjr

The reason for this is that when ω=0 (DC), the numerator is 1.