Filter
Top Products
2004 Jan 26 25
Philips Semiconductors Product specification
MPEG-2 video and MPEG-audio/AC-3
audio encoder with multiplexer
SAA6752HS
7.4.4 AUDIO INPUT PROCESSING
In order to be able to cope with analog and digital sources, the I
2
S input ports can be configured as master (analog) or
slave (digital). For the slave mode however, a sample rate converter will be involved, except for DVD-compliant audio
bypass. Table 4 reflects the different configuration possibilities.
Table 4 Audio input processing modes
Notes
1. Processing modes can be changed when SAA6752HS is in Idle mode.
2. In master mode, the external audio source must use the SAA6752HS audio clock as a clock source.
3. A sample rate conversion process will convert incoming data to a nominal 48 kHz audio frequency that is locked to
V-sync of the video input signal (if present). The sample rate converter is not enabled for DVD-compliant bypass
mode.
4. The sample rate conversion input frequency range has been selected to be compatible with class 2 SPDIF receivers.
5. 24-bit input option only applies to I
2
S input formats, in this event it will be truncated to 20 bits internally in the
SAA6752HS before processing. EIAJ formats are limited to 20 bits maximum.
6. Only for SAA6752HS/V103.
7. In systems that use 16 Mbit SDRAM due to system architecture constraints, LPCM bypass must be restricted to be
used with I and IP video encoding only. There is no constraint if 64 Mbit SDRAM is used.
8. The IEC 60958 format defines 20 bits for an audio sample, plus 4 auxiliary bits, which can be used to extend the word
length. IEC 61937 uses only 16 data bits of each IEC 60958 sub-frame. It depends on the settings of an external
SPDIF to I
2
S converter if 16, 18, 20 or 24 bits are transferred to the SAA6752HS.
9. For DVD-compliant bypass mode the audio clock must be locked to the video clock externally.
PROCESSING MODE
(1)
AUDIO CONTENT
FORMAT
INPUT SAMPLE
FREQUENCY (kHz)
NO. OF
ENCODED
BITS
ENCODED
BIT RATE
(kbit/s)
MASTER
(2)
SLAVE
(3)(4)
MPEG-1 L2 encoding LPCM at 16, 18, 20
or 24 bits
(5)
48 32 kHz ±0.1%
44.1 kHz ±0.1%
48 kHz ±0.1%
20 256, 384
DDC encoding
(6)
LPCM at 16, 18, 20
or 24 bits
(5)
48 32 kHz ±0.1%
44.1 kHz ±0.1%
48 kHz ±0.1%
20 256, 384
LPCM bypass (uncompressed
audio format)
(7)
LPCM at 16, 18, 20
or 24 bits
(5)
48 32 kHz ±0.1%
44.1 kHz ±0.1%
48 kHz ±0.1%
16 −
DVD-compliant audio bypass 16 bits
(8)
− 48 kHz
(9)
16 −