Page 144 - The Art and Science of Analog Circuit Design
P. 144
Carl Sanies
FACT SHEET FOR
CONSTANT-RESISTANCE T-COILS
damping factor
A/ = k
LT = 2L + 2M k=coupling coefficient =— and
L T
If L and C B =
Then. ~r the Constant Resistance Property
i
. v: R
and 2 r- a Quadratic (2 pole) Response at
L
RCs (l-k}R^C s
2 4(1 +k)
2 2
2
1 RCs | (l~k)R C s
and 2 an ALL PASS response atv3
2 ' 4(1+*)
V2 step response overshoot
k = .6 (CRITICAL DAMPING) 0.0%
k=.5 (FLAT DELAY) 0.4%
k=.333 (FLATAMPLITUDE) 43%
k- 0.0 (high frequency DELAY BOOST) 16.0%
SPECIAL NOTE ON m-DERfVED T-COILS.
The.nfederivefl. ^-cojlf arise from in-derived filter theory. They do not have the constant-resistance
property. The total inductance = R C. They have no bridging capacitance. They do not have a simple
2
m -!
quadratic (2 pole) response. The value of "m" implies a coupling coefficient k = ——
Figure 10-6.
Fact Sheet on Constant Resistance T-coils.
127
