cxa2074q Sony Electronics, cxa2074q Datasheet - Page 22

• Manufacturer Part Number: cxa2074q
• Description: Us Audio Multiplexing Decoder
• Manufacturer: Sony Electronics

(COMPIN)
Description of Operation [The pin numbers in parenthesis are for the CXA2074Q.]
The US audio multiplexing system possesses the base band spectrum shown in Fig. 1.
(14)
17
MVCA
PEAK DEV
kHz
50
25
(22)
(25)
STEREO LPF
(SAP IN)
(ST IN)
SAP BPF
27
24
50 – 15kHz
Fig. 2. Overall block diagram (See Fig. 3 for the dbx-TV block)
(VCO 8f
L + R
PLL
NR SW
H
)
L-R (DSB)
CANCEL
25
SAP(FM)
PILOT
5
f
LOCK
H
DET
DET
INJ.
2f
f
f
A
HL
HL
SAP
DET
HL
AM-DSB-SC
90°
0°
0°
SAP LPF
DEEMPHASIS
Fig. 1. Base band spectrum
MAIN LPF DE.EM
SUB LPF
2f
FIXED
LPF
NOISE
H
DET
I
DECODER
Fig 3. dbx-TV block
MODE
CONTROL
2
dbx-TV
PILOT
C BUS
DET
L-R
NR
(SAP OUT)
WIDEBAND
SUBVCA
I
DECODER
DEEMPHASIS
2
(24)
26
C BUS
VARIABLE
– 22 –
50
3f
HPF
LPF
H
(MAIN OUT)
I
DECODER
MODE
CONTROL
2
C BUS
(SUBOUT) (ST IN)
L + R
L – R
4.7µ
(21)
13
(9)
23
(SAP IN)
(VE OUT) (VCA IN)
4.7µ
RMS
(30)
RMS
DET
DET
4f
(25)
31
27
4.7µ
H
(22)
24
4.7µ
(MAIN IN)
(31)
12
32
(8)
NR SW
50 – 10kHz
dbx-TV NR
FM 10kHz
SAP
5f
H
VCA
A
BLOCK
dbx-TV
15
B
6f
f
TELEMETRY
H
H
to
MATRIX
= 15.734kHz
FM 3kHz
6.5f
B
CONTROL
MODE
MATRIX
H
3
f
CXA2074Q/S
(Lch)
(Rch)
to
TVSW