TDA7460ND STMicroelectronics, TDA7460ND Datasheet - Page 27

• Manufacturer Part Number: TDA7460ND
• Description: IC PROCESSOR CAR RAD SGNL SO-20
• Manufacturer: STMicroelectronics
• Type: Car Signal Processorr

Specifications of TDA7460ND

• Applications: Automotive Systems
• Mounting Type: Surface Mount
• Package / Case: 20-SOIC (7.5mm Width)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

TDA7460ND
5.5
Figure 21. Block diagram of the stereo decoder
5.5.1
MPX
100K
Description of stereo decoder
The stereo decoder part of the TDA7460ND (see
necessary to demodulate the MPX signal like pilot tone dependent mono/stereo switching
as well as "stereo blend" and "high cut" functions.
Adaptations like programmable input gain, roll-off compensation, selectable de-emphasis
time constant and a programmable fieldstrength input allow to use different IF devices.
Stereo decoder mute
The TDA7460ND has a fast and easy to control RDS mute function which is a combination
of the audioprocessor soft mute and the high-ohmic mute of the stereo decoder. If the stereo
decoder is selected and a soft mute command is sent (or activated through the SM pin) the
stereo decoder will be set automatically to the high-ohmic mute condition after the audio
signal has been softmuted.
Hence a checking of alternate frequencies could be performed. To release the system from
the mute condition simply the unmute command must be sent: the stereo decoder is
unmuted immediately and the audioprocessor is softly unmuted. Fig. 18 shows the output
signal V
the stereo decoder mute can be switched off by setting bit 3 of the Softmute byte to "0". A
stereo decoder mute command (bit 0, stereo decoder byte set to "1") will set the stereo
decoder in any case independently to the high-ohmic mute state.
If any other source than the stereo decoder is selected the decoder remains muted and the
MPX pin is connected to Vref to avoid any discharge of the coupling capacitor through
leakage currents.
3.5 ... 11dB
STEP 2.5dB
O
INGAIN
as well as the internal stereo decoder mute signal. This influence of Softmute on
NOISE BLANKER
LP 80KHz
4.th ORDER
PILOT-DET.
INFILTER
D97AU762
PLL +
STEREO
HOLDN
F19
F38
- PLOT CANC
- ROLL-OFF COMP.
- LP 25KHz
DEMODULATOR
SB CONTROL
Figure
-
MPINFL
20.) contains all functions
LEVEL INTERN
MULTIPATH
DETECTOR
REF 5V
VSBL
t=50 or 75μs
DEEMPHASIS
+ HIGHCUT
CONTROL
D
HC
A
Stereo decoder part
LP 2.2KHZ
1.th ORDER
GAIN 0..10dB
LEVEL INPUT
FM_L
FM_R
VHCCH
VHCCL
LEVEL
MPIN
MPOUT
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