cxa2134q Sony Electronics, cxa2134q Datasheet - Page 26

• Manufacturer Part Number: cxa2134q
• Description: Us Audio Multiplexing Decoder
• Manufacturer: Sony Electronics

(AUX1-R)
(1) L + R (MAIN)
(2) L – R (SUB)
(3) SAP
(4) Mode discrimination
(AUX1-L)
34
33
After the audio multiplexing signal input from COMPIN (Pin 13) passes through MVCA, the SAP signal
and telemetry signal are suppressed by STEREO LPF. Next, the pilot signals are canceled. Finally, the
L – R signal and SAP signal are removed by MAIN LPF, and the frequency response is flattened (de-
emphasized) and input to the matrix.
The L – R signal follows the same course as L + R before the pilot signal is canceled. L – R has no
carrier signal, as it is a suppressed-carrier double-sideband amplitude modulated signal (DSB-AM
modulated). For this reason, the pilot signal is used to regenerate the carrier signal (quasi-sine wave)
to be used for the demodulation of the L – R signal. In the last stage, the residual high frequency
components are removed by SUB LPF and the L – R signal is input to the dbx-TV block via the NRSW
circuit after passing through SUBVCA.
SAP is an FM signal using 5f
extracted using SAP BPF. Then, this is subjected to FM detection. Finally, residual high frequency
components are removed and frequency response flattened using SAP LPF, and the SAP signal is
input to the dbx-TV block via the NRSW circuit. When there is no SAP signal, the Pin 24 output is soft
muted.
Stereo discrimination is performed by detecting the pilot signal amplitude. SAP discrimination is
performed by detecting the 5f
noise near 25kHz after FM detection of SAP signal.
(AUX2-L) (AUX2-R)
(Lch)
from MATRIX
37
TVSW
(Rch)
36
(TVOUT-L) (TVOUT-R)
39
38
H
SURROUND
Fig. 4. Sound processor block
H
carrier amplitude. NOISE discrimination is performed by detecting the
as a carrier as shown in the Fig. 1. First, the SAP signal only is
– 26 –
BASS
TREBLE
(TOUT-R)
(TOUT-L)
44
1
4.7µ
4.7µ
48
43
(VOLIN-L)
(VOLIN-R)
VOL-R
VOL-L
(LSOUT-L)
(LSOUT-R)
3
4
CXA2134Q