cxa2054s Sony Electronics, cxa2054s Datasheet - Page 23

• Manufacturer Part Number: cxa2054s
• Description: Us Audio Multiplexing Decoder
• Manufacturer: Sony Electronics

(6) Matrix, SW1, SW2
(7) Sound processor block
The variable de-emphasis circuit transmittance and VCA gain are respectively controlled by Each of
effective value detection circuits. Each of the effective value detection circuits passes the input signal
through a predetermined filter for weighting before the effective value of the weighted signal is detected to
provide the control signal.
The signals (L+R, L-R, SAP) input to “MATRIX” become the outputs for the ST-L, ST-R, MONO and SAP
signals according to the BUS data and whether there is ST/SAP discrimination.
“SW1” switch the “MATRIX” output signal, external input signal (input to AUX1-L, R (Pins 40 and 39)) and
external forced MONO.
“SW2” switch the “SW1” output signal, external input signal (input to AUX2-L, R (Pins 42 and 41)) and
external forced MONO.
The sound processor block contains “VOLUME LIMITER”, “PREVOL”, “BASS/TREBLE” tone control
functions, “SURROUND” (quasi-surround function) and “VOLUME”.
• Prevolume
• Surround
(Lin, Lout) and (Rin, Rout) indicate the left- and right- channel I/O of the surround circuit.
“PREVOL” controls the input signal level of the sound processor block. When turning on the bass boost,
treble boost or surround, attenuate the input signal to the sound processor block using “PREVOL” so that
the signal is not dissipated inside the processor.
At “SURROUND”, the L and R differential components are phase-shifted and these components are
added to the left and right channels.
When surround is OFF (SURR=0)
Inputs are output as is.
When surround is ON (SURR=1)
{
{
{
VL :
BASS :
TREBLE :
VOLUME :
PR-VOL :
Lout=Lin
Rout=Rin
Lout=Lin –
Rout=Rin +
R=24 k (IC on-chip)
C=0.022 µF (Externally attached to Pin 45)
1–j RC
1+j RC
1–j RC
1+j RC
250 mVrms (limit level)
±12 dB (±1.7 dB/STEP at 100 Hz)
±12 dB (±1.7 dB/STEP at 10 kHz)
0 to –80 dB (–1.25 dB/STEP)
0 to –13.75 dB (–1.25 dB/STEP)
(Lin-Rin)
(Lin-Rin)
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CXA2054S