ADSP-214xx SHARC Processor Hardware Reference
12-15
Asynchronous Sample Rate Converter
Decimation Rate
The RAM in the FIFO is 512 words deep for both left and right channels.
An offset to the write address provided by the f
S
_IN counter is added to
prevent the RAM read pointer from ever overlapping the write address.
The offset is fixed by the group delay signal. A small offset, 16, is added to
the write address pointer.
Increasing the offset of the write address pointer is useful for applications
when small changes in the sample rate ratio between f
S
_IN and f
S
_OUT
are expected. The maximum decimation rate can be calculated from the
RAM word depth and GRPDLYS as (512 – 16)/64 taps = 7.75:1.
Muting Modes
The mute feature of the SRC can be controlled automatically in hardware
using the
MUTE_IN
signal by connecting it to the
MUTE_OUT
signal. Auto-
matic muting can be disabled by setting (=1) the
SRCx_MUTE_EN
bits in the
SRCMUTE
register.
Note that by default, the
SRCMUTE
register connects the
MUTE_IN
sig-
nal to the
MUTE_OUT
signal, but not vice versa.
Soft Mute
When the
SRCx_SOFTMUTE
bit in the
SRCCTL
register is set, the
MUTE_IN
sig-
nal is asserted, and the SRC performs a soft mute by linearly decreasing
the input data to the SRC FIFO to zero, (–144 dB) attenuation as
described for automatic hardware muting.
GDS
16
SRCx_FS_IP
-------------------------------
32
SRCx_FS_IP
-------------------------------
SRCx_FS_IP
SRCx_FS_OP
---------------------------------
×
onds for SRCx_FS_OP
SRCx_FS_IP
≤
(
)
sec
+
=
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Содержание SHARC ADSP-214 Series
Страница 60: ...Contents lx ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Страница 72: ...Notation Conventions lxxii ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Страница 130: ...Programming Model 2 52 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Страница 264: ...Programming Models 3 134 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Страница 290: ...Programming Model 4 26 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Страница 296: ...Programming Model 5 6 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Страница 396: ...Effect Latency 7 28 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Страница 520: ...Programming Model 10 62 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Страница 616: ...Debug Features 14 22 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Страница 656: ...Programming Model 15 40 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Страница 714: ...Programming Model 19 10 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Страница 1132: ...Register Listing A 306 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Страница 1192: ...Index I 34 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...