saa7173 NXP Semiconductors, saa7173 Datasheet - Page 3

• Manufacturer Part Number: saa7173
• Description: Analog Video Stereo Decoder
• Manufacturer: NXP Semiconductors

SAA7173 conceptual
block diagram
Stereo capture, decoding, and output
The SAA7173 handles capture and on-chip decoding of stereo
formats used in North American (BTSC with dbx noise reduction
and SAP) and Japanese (EIAJ) TV broadcasts. After capture from
the TV tuner through a Sound Intermediate Frequency (SIF) port,
TV stereo is digitized and FM or AM demodulated.The audio
standard is automatically detected, the pilot tone is investigated
(mono, stereo, dual), and the signal is decoded.
Two 16-bit audio ADCs support capture of audio signals from
nonstandard sources such as video cameras,VCRs, and AM (mono)
or FM (stereo) radio through two stereo line-in inputs. An analog
audio pass-through enables an incoming signal to be rerouted
without processing and output through an external loop-back
cable to a sound card. A field-locked audio clock samples a
constant number of audio clocks per video field, guaranteeing
synchronization of audio and video streams.
Decoded digital audio is output through an I
reconverted to analog (by on-chip stereo DACs) and rerouted
through a loop-back cable to a sound card.
SAA7173
SAA7174
SAA717x family audio feature comparison
TV sound (SIF)
two analog audio
stereo pairs
five analog
video inputs:
CVBS, S-Video
GPIO
interrupt
loop-back
audio
·
·
SAA7173
AUDIO INTERFACE
PROGRAMMABLE I/O
IRQ SELECTION/MAP
ANALOG SIF/
INTERFACE
INTERFACE
mono
ANALOG
ANALOG
AUDIO
VIDEO
·
·
2
S port or can be
FM-radio
·
32 kHz, 44.1 kHz, 48 kHz
Dual-FM
SOUND DECODER
CLOCK SYNC
COMB FILTER
A2/
(BTSC+dbx, EIAJ,
·
DECODER
FM,AM)
NICAM
·
analog audio pass-through
Advanced audio feature processing
The SAA7173 incorporates advanced on-chip audio feature
processing to improve user control and perceived audio quality.
Philips Incredible Mono™ adds stereo-like sound impression to
monaural audio signals. Philips Incredible Stereo™ widens the
stereo image, immersing the listener in the screen action.
Additional on-chip audio features include volume, balance, bass/
treble controls, and automatic volume leveling (AVL).
Versatile external interface
The SAA7173's flexible design, reusable components, and versatile
external interfaces lower BOM and cost and support advanced
decoder configurations. Such flexibility is made possible, in part,
through 28 general purpose I/O (GPIO) pins, initially dedicated
to provide a digital video port, an I
and peripheral interrupt input.
GPIO pins can be reassigned if dedicated functions are not
needed in a specific product configuration. In addition, unassigned
pins can be utilized for GPIO under direct software control.
PROGRAMMING
REGISTERS
(+ dbx)
SCALER
BTSC
VIDEO
·
(bass, treble, volume,
balance, AVL, Philips
Incredible Sound)
AUDIO FEATURE
PROCESSING
SAP
·
MATRIX &
GAMMA
EIAJ Incredible Mono
·
DAC (2)
Incredible Stereo
·
I
2
VIDEO PORT
C INTERFACE
AUDIO MUX
FORMAT
2
S digital audio output port,
I S
2
I
2
C
(to loopback cable
or headphones)
from EEPROM
analog stereo
control data,
digital audio
digital video
config data