UMA1021M/C2 Philips Semiconductors (Acquired by NXP), UMA1021M/C2 Datasheet - Page 15

• Manufacturer Part Number: UMA1021M/C2
• Description: UDA1380; Stereo Audio Coder-decoder For MD, CD And MP3
• Manufacturer: Philips Semiconductors (Acquired by NXP)

Philips Semiconductors
8.4
The interpolation digital filter interpolates from 1 to 64f
to 128f
interpolator is equipped with several sound features like
volume control, mute, de-emphasis and tone control.
Table 4 Interpolation filter characteristics
8.4.1
Muting the DAC will result in a cosine roll-off soft mute,
using 4
44.1 kHz sampling frequency). The cosine roll-off curve is
illustrated in Fig.8. These cosine roll-off functions are
implemented for both the digital mixer and the master mute
inside the DAC data path, see Section 8.8.
2003 Apr 04
Pass-band ripple
Stop band
Dynamic range
handbook, halfpage
Stereo audio coder-decoder
for MD, CD and MP3
Fig.8
factor
mute
0.8
0.6
0.4
0.2
s
Interpolation filter (DAC)
, by cascading FIR filters, see Table 4. The
ITEM
1
0
DIGITAL MUTE
0
32 = 128 samples in normal mode (or 3 ms at
Mute as a function of raised cosine roll-off,
displayed assuming 44.1 kHz.
5
0 to 0.45f
>0.55f
0 to 0.45f
CONDITION
10
s
s
s
15
20
>135
0.025
60
VALUE (dB)
t (ms)
MGU119
25
s
or
15
8.4.2
In addition, there are basic sound features:
8.5
The noise shaper consists of two mono 3rd-order noise
shapers and one time-multiplexed stereo 5th-order noise
shaper.
The order of the noise shaper can be chosen between
3rd-order (which runs at 128f
at 64f
The preferable choice for the noise shaper order is:
The noise shaper shifts in-band quantization noise to
frequencies well above the audio band. This noise shaping
technique enables high signal-to-noise ratios to be
achieved. The noise shaper output is converted into an
analog signal using an FSDAC.
dB-linear volume control using 14-bit coefficients in
steps of 0.25 dB: range 0 to 78 dB maximum
suppression and
and mixing volume control
De-emphasis for 32, 44.1, 48 and 96 kHz for both
channel 1 and 2 (selectable independently)
Treble, which is selectable gain for high frequencies
(positive gain only), the edge frequency of the treble is
fixed (depends on the sampling frequency). Can be set
for left and right independently:
– Two settings: f
– Both settings have 0 to 6 dB gain range in steps
Bass boost, which is selectable gain for low frequencies
(positive gain only). The edge frequency of the bass
boost is fixed and depends on the sampling frequency.
Can be set for left and right independently:
– Two settings: f
– First setting: 0 to 18 dB gain range in steps of 2 dB
– Second setting: 0 to 24 dB gain range in steps
3rd-order noise shaper is preferred at low sampling
frequencies, for instance between 8 and 32 kHz. This is
for preventing out-of-band noise from the noise shaper
to move into the audio band
5th-order noise shaper is normally used at higher
sampling frequencies, normally from 32 to 100 kHz.
sampling frequency is 44.1 kHz
of 2 dB
sampling frequency is 44.1 kHz
of 2 dB.
s
) via bit SEL_NS in the L3-bus or I
Noise shaper
S
OUND FEATURES
c
c
= 250 Hz and f
= 1.5 kHz and f
dB: applies to both master volume
s
) and 5th-order (which runs
c
c
Product specification
= 300 Hz, assuming
= 3 kHz, assuming
UDA1380
2
C-bus register.