STV0297E STMicroelectronics, STV0297E Datasheet - Page 2

• Manufacturer Part Number: STV0297E
• Description: QAM demodulator IC
• Manufacturer: STMicroelectronics

Description
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Description
The STV0297E is a complete single-chip QAM (quadrature amplitude modulation)
demodulation and FEC (forward error correction) solution that performs sampled IF to
transport stream (MPEG-2 or MPEG-4) block processing of QAM signals. It is intended for
the digital transmission of compressed television, sound, and data services over cable. It is
fully compliant with ITU-T J83 Annexes A/C or DVB-C specification bitstreams (ETS 300
429, “Digital broadcasting systems for television, sound and data services - Framing
structure, channel coding and modulation - Cable Systems”). It can handle square (16, 64,
256-QAM) and non-square (32, 128-QAM) constellations.
Japanese DBS systems require a transport stream multiplex frame (TSMF) layer to carry
digital signals over cable systems. When the recovered transport stream is a multiplex
frame, the STV0297E post-processes it to extract a single transport stream. Automatic
detection of the TSMF layer is provided.
The chip integrates an analog-to-digital converter that delivers the required performance to
handle up to 256-QAM signals in a direct IF sampling architecture, thus eliminating the need
for external downconversion.
The IF can be up to 57 MHz while the STV0297E allows the sampling clock to be freely
selected from a given range (and meeting constraints derived from SAW filter and symbol
rate characteristics). All further processing is fully digital, so no external feedback loop is
required. The STV0297E handles a wide range of symbol rates, ranging from the highest
practical rates to rates as low as 0.87 Mbaud, even if there is a significant frequency offset.
The STV0297E is thus an excellent candidate for integration in world-wide set-top boxes,
cable modems and cable tuners.
It provides all demodulation and FEC functions required for the recovery of QAM modulated
bitstreams with outstanding BER results. In addition, it includes several features that give
simple and immediate access to various quality and status monitoring parameters.
The STV0297E also provides outputs, such as delayed AGC or a noise-free I²C bus
dedicated to tuner control, which simplifies the design of high-quality application boards.
These outputs are mapped to a 10-bit GPIO matrix allowing a good optimization of the
application PCB. The STV0297E outputs error corrected MPEG transport streams in a wide
variety of formats, including the DVB common interface format with programmable data
clock frequency. The STV0297E interfaces seamlessly to the packet demultiplexers
embedded in the ST backend product families.
The dynamic performance of the STV0297E has been significantly improved and is close to
theoretical limits thanks to new demodulation algorithms and a wide equalizer allowing the
STV0297E to correct both pre and post echoes.
STV0297E