CXA2064M
Description of Operation
The US audio multiplexing system possesses the base band spectrum shown in Fig. 2.
PEAK DEV
AM-DSB-SC
kHz
50
50
L-R
dbx-TV
NR
25
5
25
15
SAP
dbx-TV NR
FM 10kHz
50 – 10kHz
TELEMETRY
FM 3kHz
3
L + R
50 – 15kHz
f
fH
2fH
3fH
4fH
5fH
6fH
6.5fH
fH = 15.734kHz
Fig. 2. Base band spectrum
2fHL0°
fHL90°
fHL0°
ST.ID
PLL
(VCO 8fH)
PILOT DET
MODE CONTROL
MAIN LPF DE.EM
STEREO LPF
(MAIN IN)
16
(COMPIN)
7
(MAIN OUT)
15
PILOT
CANCEL
4.7µ
L + R
SUB LPF
(SUBOUT)
MATRIX
(TVOUT-L)
L-R (DSB)
DET
2
(STIN)
23
10k
1
NR SW
(TVOUT-R)
22
4.7µ
A
B
dbx-TV
BLOCK
SAP(FM)
DET
SAP LPF
SAP BPF
(SAP OUT)
28
(SAP IN)
INJ.
LOCK
27
4.7µ
MODE
CONTROL
NOISE
DET
SAP.ID
SAP
DET
MODE CONTROL
Fig. 3. Overall block diagram (See Fig. 4 for the dbx-TV block)
(ST IN)
VARIABLE
DEEMPHASIS
FIXED
DEEMPHASIS
NR SW
1
(VE OUT)
25
(VCA IN)
24
A
B
VCA
to MATRIX
(SAP IN)
27
4.7µ
HPF
LPF
RMS
DET
LPF
RMS
DET
Fig 4. dbx-TV block
– 14 –
SONY [ SONY CORPORATION ]
