TDA9855WP Philips Semiconductors, TDA9855WP Datasheet - Page 11

• Manufacturer Part Number: TDA9855WP
• Description: I2C-bus controlled BTSC stereo/SAP decoder and audio processor
• Manufacturer: Philips Semiconductors

Philips Semiconductors
S
The subwoofer or the surround mode can be activated with
the control bit SUR (see Table 6). A low bit provides an
output signal
selects surround mode and provides an output signal
1
with a range from +14 to 14 dB in 2 dB steps on top of the
main channel control to the output pin OUTS. The last
setting is the mute position (see Table 11). The capacitor
C35 at pin SW provides a 230 Hz low-pass filter in
subwoofer mode. In surround mode this capacitor should
be disconnected. If balance is not in mid position the
selected left and right output levels will be combined.
M
The mute function can be activated independently with the
last step of volume or subwoofer/surround control at the
left, right or centre output. By setting the general mute bit
GMU via the I
All channels include an independent zero-crossing
detector. The zero-crossing mute feature can be selected
via bit TZCM:
In the zero-crossing mode a change of the GMU bit is
activated but not executed. The execution is enabled at
the next zero-crossing of the signal. To avoid a large delay
of mute switching, when very low frequencies are
processed, or the output signal amplitude is lower than the
DC offset voltage, the following I
needed:
Adjustment procedure
C
Apply the composite signal (from the FM demodulator)
with 100% modulation (25 kHz deviation) L + R;
f
monitoring line output (500 mV 20 mV). Store the setting
in a non-volatile memory. Adjustment of the spectral and
1997 Nov 04
i
2
UBWOOFER
OMPOSITE INPUT LEVEL ADJUSTMENT
= 300 Hz. Set input level control via the I
UTE
(L
TZCM = 0: forced mute with direct execution
TZCM = 1: execution in time with signal zero-crossing.
A first transmission for mute execution
A second transmission approximately 100 ms later,
which must switch the zero-crossing mode to forced
mute (TZCM = 0)
A third transmission to reactivate the zero-crossing
mode (TZCM = 1). This transmission can take place
immediately, but must follow before the next mute
execution.
I
decoder and audio processor
2
C-bus controlled BTSC stereo/SAP
R). The signal is fed through a volume control stage
;
SURROUND SOUND CONTROL
1
2
2
C-bus all audio part outputs are muted.
(L + R) in subwoofer mode, a high bit
2
C-bus transmissions are
2
C-bus
11
wideband expander is performed via the stereo channel
separation adjust.
A
M
Manual adjustment is necessary when no dual tone
generator is available (e.g. for service).
After every power-on, the alignment data and the input
level adjustment data must be loaded from the non-volatile
memory.
T
Due to possible internal and external spreading, the timing
current can be adjusted via the I
recommended by dbx.
IMING CURRENT FOR RELEASE RATE
UTOMATIC ADJUSTMENT PROCEDURE
ANUAL ADJUSTMENT
Capacitors of external inputs EIL and EIR must be
grounded
Composite input signal L = 300 Hz, R = 3.1 kHz,
14% modulation for each channel; volume gain +16 dB
via the I
bit to logic 1 during adjustment procedure
Effects, AVL, loudness off
Selector setting SC0, SC1 and SC2 = 0, 0, 0
(see Table 12)
Line out setting bits: STEREO = 1, SAP = 0
(see Table 21)
Start adjustment by transmission ADJ = 1 in register
ALI3; the decoder will align itself
After 1 second, stop alignment by transmitting ADJ = 0
in register ALI3 read the alignment data by an I
read operation from ALR1 and ALR2
(see Chapter “I
non-volatile memory; the alignment procedure
overwrites the previous data stored in ALI1 and ALI2
Disconnect the capacitors of external inputs from
ground.
Spectral and wideband data have to be set to 10000
(middle position for adjustment range)
Composite input L = 300 Hz; 14% modulation
Adjust channel separation by varying wideband data
Composite input L = 3 kHz; 14% modulation
Adjust channel separation by varying spectral data
Iterative spectral/wideband operation for optimum
adjustment
Store data in non-volatile memory.
2
C-bus; to avoid annoying sound level set GMU
2
C-bus protocol”) and store it in a
2
C-bus (see Table 25) as
Product specification
TDA9855
2
C-bus