TDA7412 View Datasheet(PDF) - STMicroelectronics
Part Name
Description
MFG CO.
'TDA7412' PDF : 56 Pages View PDF
TDA7412
2.3 NOTES TO THE CHARACTERISTICS
2.3.1 Intermodulation Suppression
α2
=
----V-----O---(---s---i--g----n----a----l-)---(--a----t--1----k---H----z----)----
VO(spurious )(at1kHz)
;fs
=
(2 ⋅ 10kHz ) – 19kHz
α3
=
----V-----O----(--s----i-g----n----a----l--)--(--a----t--1----k---H-----z---)----
VO(spurious )(at1kHz)
;fs
=
(3 ⋅ 13kH z) – 38kH z
measured with: 91% pilot signal; fm = 10kHz or 13kHz.
2.3.2 Traffic Radio (V.F.) Suppression
α 57( V.W .F)= -----------------V----O----(--s----i--g---n----a----l--)--(---a---t---1---k---H-----z---)-----------------
VO(spurious)(at1kHz ± 23kHz)
measured with: 91% stereo signal; 9% pilot signal; fm=1kHz; 5% subcarrier (f=57kHz, fm=23Hz AM, m=60%)
2.3.3 SCA ( Subsidiary Communications Authorization )
α67
=
-----V----O----(--s----i-g----n----a----l--)--(--a----t--1----k---H----z----)----
VO(sp urious) (at1 kHz)
;f
s
=
(2 ⋅ 38kH z) – 67kHz
measured with: 81% mono signal; 9% pilot signal; fm=1kHz; 10%SCA - subcarrier ( fS = 67kHz, unmodulated ).
2.3.4 ACI ( Adjacent Channel Interference )
α 114
=
-----V----O----(--s----i-g----n----a----l--)--(--a----t--1----k---H----z----)----
V O ( s p u r i o u s ) ( a t 4 kHz )
;f
s
=
110kHz – (3 ⋅ 38kHz )
α 190
=
-----V----O----(--s----i-g----n----a----l--)--(--a----t--1----k---H----z----)----
V O ( s p u r i o u s ) ( a t 4 kHz )
;f
s
=
186kHz – (5 ⋅ 38kHz )
measured with: 90% mono signal; 9% pilot signal; fm=1kHz; 1% spurious signal ( fS = 110kHz or 186kHz, un-
modulated).
2.4 NOISE BLANKER PART
2.4.1 Features:
s AM and FM mode
s internal 2nd order 140kHz high-pass filter for MPX path
s internal rectifier and filters for AM-IF path
s programmable trigger thresholds
s trigger threshold dependent on high frequency noise with programmable gain
s additional circuits for deviation- and fieldstrength-dependent trigger adjustment
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