CAP 3001 A
2.1.13. Digital Mixing Systems
er is the phase detector of the PLL; the other parts of the
PLL (loop filter and VCO) are realized in the DSP. The
inphase mixer outputs information concerning the level
of the pilot tone to the DSP to allow a decision “FM-ste-
reo” or “FM-mono”. The time relation between the mixer
sequences of stereo-demodulator and pilot-demodula-
tors is fixed.
2.1.13.1. Pilot Demodulator PILMX
The entire system is synchronized with the pilot tone of
the FM-stereo channel. In the pilot-demodulator 2 mix-
ersworkinginquadratureareused. Thequadraturemix-
ASU
ASU
HIGH
DETECT
PASS
AMMIX
A
LPF
02
PILOT
NOTCH
LPF
23
LPF
34
36
36
ASU
ASU
3
3
2
2
Main 1
Main 2
D
D
AMMIX
A
LPF
02
PILOT
NOTCH
LPF
23
LPF
34
LPF
35
8
8
PILMIX
PILMIX
LPF
23
3
LPF
35
A
ARI/
RDS
LPF
01
18
DSP
D
ARI
MIX
LPF
24
LPF
45
6
6
4
4
LPF
12
2
ARI
MIX
LPF
24
LPF
45
A
A
LPF
06
540
864
Level
POT
D
D
LPF
05
Fig. 2–5: Digital signal processing blocks, input side
NOISE
SHA-
PING
4
3
D
D
2
INT
12
4
4
INT
28
A
A
DSP
NOISE
SHA-
PING
4
3
INT
12
INT
28
2
Fig. 2–6: Digital signal processing blocks, output side
MICRONAS INTERMETALL
9
MICRONAS [ MICRONAS ]
