Philips Semiconductors
Decoder for traffic warning (VWF) radio
transmissions
FILTER INFORMATION
Gain
Amplifier conditions: Go >> Gv and Go >> 2 ⋅ Q2
Gv = –-p---2----+-----p----R---------3--C--------⋅--1----C-----+-----1----C------⋅----2--C---------2-R----------+-1--------p--R-⋅---------C---1------------1---⋅-------R----------2R----------⋅1-----R-----+----3------R----⋅-----2-C----------1----------⋅------C--------2------ , in which p = jω and Gv = V-V----o-i .
Product specification
TDA1579
TDA1579T
Resonance frequency
GENERAL EQUATION
ωr =
-------------------------------1---------------------------------
R-R----1-1----+-⋅---R-R----2-2-- ⋅ R3 ⋅ C1 ⋅ C2
C1 = C2 = C
---------------------1----------------------
C R-R----1-1----+-⋅---R-R----2-2-- ⋅ R3
Gain at ω = ωr
Quality
−Gvr = C-----1---C--+--2---C-----2-- ⋅ RR-----31--
12-- ⋅ RR-----31--
Q=
--C---C-1---1--+---⋅--C-C----2-2-- ⋅ R-----3----R-(---R-1---1--⋅---R+----2-R-----2---)--
12-- -R----3----R-(---R-1---1--⋅---R+----2-R-----2---)--
Recommended components
C1, C2
and
R1, R2, R3
or
C1, C2
and
R1, R2, R3
metallized polycarbonate film (MKC) capacitors; ± 5%
metal film (MR) resistors; ± 2%
metallized polyester film (MKT) capacitors; ± 5%
carbon film (CR) resistors; ± 2%
C1 = C2 = C
R2 < < R1
--------------1---------------
C R2 ⋅ R3
12-- ⋅ RR-----31--
12-- ⋅ RR-----32--
May 1992
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