TDA7410ND Datasheet, PDF (21/34 Pages) STMicroelectronics – Signal processor for car radio applications

TDA7410ND
Description of stereodecoder
To adjust the external LEVEL voltage to the internal range two values must be defined: the
LEVEL gain LG and VSBL. To adjust the voltage where the full channel separation is
reached (VST) the LEVEL gain LG has to be defined. The following equation can be used to
estimate the gain:
L_G = _F-----_i-_e----_l--_d-----_s---_t--_r--_e---_n---_g----_t-_h---^R---_v--^E-_o---^F-_l--_t-⁵-_a---^Vg----_e----_[--_S-----_T----_E----_R-----_E----_O-----_]---
The gain can be programmed through 4 bits in the "Level Gain" byte. The MONO voltage
VMO (0dB channel separation) can be choosen selecting 33, 42, 50 or 58% of REF5V.
Figure 14. Relation between internal and external LEVEL voltage and setup of Stereoblend
INTERNAL
VOLTAGES
REF 5V
VSBL
SETUP OF VST
LEVEL INTERN
INTERNAL
VOLTAGES
REF 5V
LEVEL
58%
50%
VSBL 42%
33%
SETUP OF VMO
LEVEL INTERN
VMO
VST
t
FIELDSTRENGHT VOLTAGE
D97AU639
VMO
t
VST
FIELDSTRENGHT VOLTAGE
6.8
Highcut Control
The highcut control setup is similar to the stereoblend control setup : the starting point
VHCH can be set with 2 bits to be 42, 50, 58 or 66% of REF5V whereas the range can be
set to be 17 or 33% of VHCH (see Figure 15).
Figure 15. Highcut characteristics
LOWPASS
TIME CONSTANT
3•τ_Deemp
τ_Deemp
VHCL
VHCH FIELDSTRENGHT
D97AU640
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