uda1355h-n2 NXP Semiconductors, uda1355h-n2 Datasheet - Page 15

• Manufacturer Part Number: uda1355h-n2
• Description: Stereo Audio Codec With Spdif Interface
• Manufacturer: NXP Semiconductors

Philips Semiconductors
7.6.3
In the decimator there are two digital DC blocking circuits.
The first blocking circuit is in front of the volume control to
remove DC bias from the ADC output. The DC bias is
added in the ADC to prevent audio band Idle tones
occurring in the noise shaper. With the DC components
removed, a signal gain of 24 dB can be achieved.
The second blocking circuit removes the DC components
introduced by the decimator stage.
7.6.4
Bit OVERFLOW = 1 when the output data in the left or
right channel is larger than 1.16 dB of the maximum
possible digital swing. This condition is set for at least
512f
time-out is reset for each infringement.
7.7
7.7.1
The audio feature processor provides automatic
de-emphasis for the IEC 60958 bitstream.
In microcontroller mode all features are available and
there is a default mute on start up.
7.7.2
The digital filter interpolates from 1f
1f
The stereo interpolator has the following basic features:
2003 Apr 10
s
24-bit data path
Mixing of two channels:
– To prevent clipping inside the core, there is an
– Position of mixing can be set before or after bass
– Master volume control and mute with independent left
– Independently left and right channel de-emphasis,
– Output of the mixer is to the I
Full FIR filter implementation for all the upsampling
filters
Integrated digital silence detection for left and right
channels with selectable silence detection time
Stereo audio codec with SPDIF interface
to 128f
s
automatic signal level correction of 6 dB scaling
before mixing and +6 dB gain after digital volume
control
boost and treble
and right channel settings for balance control
volume control and mute (no left or right)
decoder.
cycles (that is 11.6 ms at f
Analog output
DC
O
A
I
NTERPOLATING FILTER
s
UDIO FEATURE PROCESSOR
VERLOAD DETECTION
, by cascading a half-band filter and a FIR filter.
FILTERING
s
= 44.1 kHz). This
2
S-bus or IEC 60958
s
to 64f
s
, or from
15
The stereo interpolator has the following sound features:
Support for 1f
audio via I
Linear volume control using 14-bit coefficients with
0.25 dB steps: range 0 to 78 dB and
master volume and mixing volume control
A cosine roll-off soft mute with 32 coefficients; each
coefficient is used for four samples, in total 128 samples
are needed to fully mute or de-mute (approximately
3 ms at f
Independent selectable de-emphasis for 32, 44.1, 48
and 96 kHz for both channels
Treble is the selectable positive gain for high
frequencies. The edge frequency of the treble is fixed
and depends on the sampling frequency. Treble can be
set independently for left and right channel with two
settings:
– f
– f
Normal bass boost is the selectable positive gain for low
frequencies. The edge frequency of the bass boost is
fixed and depends on the sampling frequency. Normal
bass boost can be set independently for the left and right
channel with two sets:
– f
– f
Resonant bass boost optional function is selected if
bit BASS_SEL = 1. When selected, the characteristics
are determined by six 14-bit coefficients. Resonant bass
boost controls the left and right channel with the same
characteristics. When resonant bass boost is selected,
the treble control also changes to a single control for
both channels following the gain setting of the left
channel.
A software program is available for users to generate the
required six 14-bit coefficients by entering the desired
centre frequency (f
sampling frequency (f
Figs 7 and 8).
2 dB steps
2 dB steps.
2 dB steps
2 dB steps.
c
c
c
c
= 1.5 kHz; f
= 3 kHz; f
= 250 Hz; f
= 300 Hz; f
s
= 44.1 kHz)
2
S-bus.
s
s
and 2f
s
s
= 44.1 kHz; 0 to 6 dB gain range with
s
= 44.1 kHz; 0 to 18 dB gain range with
= 44.1 kHz; 0 to 24 dB gain range with
= 44.1 kHz; 0 to 6 dB gain range with
c
), positive or negative peak gain,
s
s
) and shape factor (see
input data rate and 192 kHz
Preliminary specification
UDA1355H
dB; hold for