CAP 3001 A
2.1.4. Operating Modes
3) XDS-mode
The CAP 3001 A possesses 4 main operating modes:
1) MPX-mode
Inthismodethereisanexternaldigitalsource(XDS, e.g.
aCDplayer)whichsendsitsdigitaldatatotheCAP3001
A for further processing and for the reconverting to ana-
log signals. The CAP 3001 A can be adapted to the sam-
pling rate prescribed by the external digital source; in
addition the input systems of the CAP 3001 A remain ac-
tive in order to monitor the traffic information (ARI/RDS).
In this mode, the CAP 3001 A receives the multiplex sig-
nal of an FM transmission, containing sum and differ-
ence channel, the pilot tone and the signals needed for
travel information (ARI, RDS). The FM-demodulation
has to take place inside the conventional tuner. The mix-
ing of the difference band is done by an analog mixer in
frontoftheA/D-convertersinordertoachievetheneces-
sary quality for FM stereo. The ARI and RDS signals and
the pilot tone are extracted digitally.
4) AM-IF mode
In this mode, the CAP 3001 A receives input signals in
the AM-IF range (i.e. 450 to 460 kHz). By a special ana-
log mixer in front of the A/D conversion, the AM signal is
mixed down to a frequency of 19 kHz. AM mono and ste-
reo (C-QUAM) are demodulated in the DSP software.
2) AF-mode
In this mode the CAP 3001 A works transparently; the in-
coming signals are only A/D-converted and then trans-
mitted to the DSP core.
MPX
LF
LR
FM
Tuner
FM
IF
FMLEVEL
FMTUNOUT
FMOSCIN
CAP 3001 A
AMOSCIN
RF
RR
AMTUNOUT
AM
Tuner & IF
AMIF
µController
Fig. 2–2: CAP 3001 A system overview
6
MICRONAS INTERMETALL
MICRONAS [ MICRONAS ]
