AD1970_15 Datasheet, PDF (1/20 Pages) Analog Devices – Digital BTSC Encoder with Integrated ADC and DAC

FEATURES
Complete BTSC encoder
Pilot tone generator
Includes subcarrier modulation
Channel separation: 30 dB
Bandwidth up to 14 kHz
Stereo analog or digital input
Phat-Stereo™ algorithm for stereo image enhancement
Dialog enhancement function for playing wide dynamic
range video sources over built-in TV speakers
Includes L − R dual-band compressor
I²C port for control of modes, effects, and parameters
Analog input performance
74 dB dynamic range
−72 dB THD + N
Digital input performance
87 dB dynamic range
−83 dB THD + N
Integrated op amps for analog inputs and outputs
Single-ended output reduces external part count
Integrated PLL generates all clocks from composite video,
48 kHz sample clock, or high speed master clock
Sync stripper to recover video clock from composite
video signal
Output level control for setting aural carrier deviation
Macrovision™-compliant
Dolby™ RF mode-compatible
48-pin LQFP plastic package
Digital BTSC Encoder
with Integrated ADC and DAC
AD1970
APPLICATIONS
Digital set top box
DVD player
DVD recorder
GENERAL DESCRIPTION
The AD1970 is a complete analog or digital-in, analog-out
BTSC encoder which includes pilot-tone generation and sub-
carrier mixing functions. The stereo ADC provides the means
for digitization of the analog baseband audio signal. A built-in
high performance DAC is provided to output the BTSC base-
band composite signal. The output of the AD1970 can be
connected with minimal external circuitry to the input of a
4.5 MHz aural FM modulator.
In addition to the digital BTSC encoder, the AD1970 includes a
stereo image enhancement function, Phat Stereo, to increase the
sense of spaciousness available from closely spaced TV
loudspeakers. A dialog enhancement algorithm solves the
problem of playing wide dynamic range sources over limited-
performance TV speakers and amplifiers. An I²C port allows
control of the AD1970’s registers and parameters.
The AD1970 utilizes ADI’s patented multibit Σ-Δ architecture to
provide BTSC performance of up to 87 dB dynamic range and a
THD+N of −83 dB.
The AD1970 includes patented BTSC stereo TV technology
licensed from THAT Corporation.
ANALOG L/R
INPUTS
DIGITAL AUDIO 3
INTERFACE
COMPOSITE
VIDEO
I²C I/O ⁴
GROUP
FUNCTIONAL BLOCK DIAGRAM
ADC
ADC
DECIMATION
FILTER
SYNC
PLL
STRIPPER
AD1970
BTSC
ENCODER
CORE
I²C PORT
CONTROL
REGISTERS
ADC
VOLUME
CONTROL
DAC
BTSC
ENCODED
OUTPUT
ANALOG
BIAS
Figure 1.
Rev. 0
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