U4275B Datasheet, PDF (4/12 Pages) TEMIC Semiconductors – FM-Receiving Condition Analyser and Multipath Noise Cancellation

U4275B
INT
+5V
25 kW
INT
TELEFUNKEN Semiconductors
The controller element detects the absolute value of
occuring multipath interference. This information is
stored in a capacitor which must be connected externally
to MPFIL. The capacitor voltage can be interrogated by
the system controller via ANAOUT.
FIL19 / FIL26
94 8654
Certain types of abruptly occuring interference with
reception require a fast reaction by the receiver. INT
m ^{signals such events to other circuit parts by means of}
40- s-wide pulses (low active). The output voltage is
limited to 5 V to permit direct activation of a system
controller. A monoblend function can thus be activated on
simple receivers. On antenna-diversity receivers, INT
can activate switchover between antennas.
W _FIL19 100 k
100 nA
94 8657
CCFIL
W _CCFIL 100 k
W ^FIL26 100 k
100 nA
100 nA
94 8655
The controller element detects the absolute value of
occuring common channel interference. This information
is stored in a capacitor which must be connected
externally to CGFIL. The capacitor voltage can be
selected by the system controller and then available via
ANAOUT.
MPFIL
94 8658
In order to differentiate the various types of interference,
the amplitudes of a few spectral components of the
fieldstrength signal are determined and filtered in FIL19
and FIL26 for further processing.
VREF
V_S
30 k
VREF
W MPFIL 100 k
94 8656
100 nA
30 k
94 9669
IF Mute is activated, the reference voltage VREF will
apply to the output MPXOUT. A capacitor of 100 nF
should be connected at VREF for filtering.
4
Preliminary Information
Rev. A1: 14.03.1995