TDA7460ND STMicroelectronics, TDA7460ND Datasheet - Page 32

• 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

Stereo decoder part
5.6.4
5.7
5.8
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Over deviation detector
If the system is tuned to stations with a high deviation the noise blanker can trigger on the
higher frequencies of the modulation. To avoid this wrong behavior, which causes noise in
the output signal, the noise blanker offers a deviation dependent threshold adjustment.
By rectifying the MPX signal a further signal representing the actual deviation is obtained. It
is used to increase the PEAK voltage. Offset and gain of this circuit are programmable in 3
steps with the bits D6 and D7 of the stereo decoder byte (the first step turns off the detector,
see
Functional description of the multipath detector
Using the internal detector the audible effects of a multipath condition can be minimized. A
multipath condition is detected by rectifying the 19 kHz spectrum in the fieldstrength signal.
Selecting the "internal influence" in the configuration byte, the channel separation is
automatically reduced during a multipath condition according to the voltage appearing at the
MPOUT pin.
To obtain a optimal performance an adaptation is necessary. Therefore the gain of the
19 kHz bandpass is programmable in four steps as well as the rectifier gain. The attack and
decay times can be set by the external capacitor value.
Test mode
During the test mode which can be activated by setting bit D0 of the testing byte and bit D5
of the subaddress byte to "1" several internal signals are available at the CASSR pin. During
this mode the input resistance of 100 kOhm is disconnected from the pin. The internal
signals available are shown in the software specification.
Figure 27. Block diagram of the multipath detector
Figure
LEVEL
MPIN
18.).
MP ENABLE
15K
BANDPASS
19KHz
2 BITS
GAIN
RECTIFIER
2 BITS
GAIN
D98AU862
DC=1μ
VDD
-
MPOUT
220nF
int. INFLUENCE
TO PHONE_GND - APR
to SB
TDA7460ND