ST HDTV卫星电视调谐解调方案

ST公司的HDTV卫星电视硅调谐器STV6110A和多标准解调器STV0903非常适合用在高性价比的高清卫星电视. STV6110A卫星电视调谐器是专用于数字TV广播的直接变换(零中频)接收器,单电源3.3V工作,工作频率950 MHz 到2150 MHz;而STV0903多标准解调器支持DVB-S, DIRECTVTM legacy 和DVBS2 (QPSK 和8PSK)等格式.本文介绍了STV6110A和STV0903的主要特性,方框图以及采用STV6110A和STV0903的前端系统方框图.

STMicroelectronics Introduces Silicon Tuner and Single-Channel DVB-S2 Demodulator to Enable Cost Effective HDTV Satellite Consumer Equipment

The STV6110A satellite tuner is a direct conversion (zero IF) receiver dedicated to digital
TV broadcasting. On the RF input is a low noise amplifier (LNA), with buffer to supply the RF output for loop-through, and a continuously variable gain LNA to ensure an optimal signal level for the two mixers. Each mixer, which down-converts the signal to baseband, is followed by a low-pass filter and amplifier. The baseband gain can be varied by programming a register via the I2C bus.
The LO signals are provided by an integrated PLL which contains an on-chip voltage controlled oscillator (VCO) meeting stringent phase noise requirements. The PLL loop filter is integrated. The LO frequencies are programmable.

The comparison frequency for the phase frequency detector (PFD) is generated by dividing the crystal oscillator reference frequency. The crystal frequency can be from 16 MHz to 32 MHz depending on application.

STV6110A 主要特性:
■RF to baseband 8PSK/QPSK direct conversion
■Single 3.3 V DC supply
■Input frequency range 950 MHz to 2150 MHz
■Supports 1 to 45 Msymbol/s
■On-chip RF loop-through
■Fully integrated PLL frequency synthesizer for DVB-S2 (including loop filter)
■Extremely low phase noise compliant with DVB-S2 requirements
■Low external component count
■Low power consumption
■Flexible crystal frequency output to drive the demodulator IC
■Continuously variable gain: 0 to 65 dB
■Additional and programmable gain on baseband amplifier: 0 to 16 dB
■Programmable 5- to 36-MHz cut-off frequency (butterworth 5th-order baseband filters)
■Compatible with 5-V and 3.3 V I2C bus

图1.STV6110A方框图
STV0903多标准解调器

Multi-standard advanced demodulator for satellite digital TV and data services set-top boxes STV0903 is a high performance satellite demodulator capable of handling DVB-S,
DIRECTVTM legacy and DVBS2 (QPSK and 8PSK) constant coding and modulation signals for satellite broadcast.

STV0903主要特性:
■Demodulation
–DIRECTVTM and DVBS QPSK
–DVBS2 QPSK and 8PSK
–Digital Nyquist root filter with 0.20, 0.25, 0.35 excess bandwidth factors
■Decoding
–Up to 95 mega channel bits per second (Mcbps) at input to DVBS2 FEC
–Up to 130 Mcbps DVBS or DIRECTVTM at input to legacy FEC
■Interfaces
–Dedicated 27 MHz clock generation for back-end decoder
–I2C serial bus interface
–JTAG interface - boundary scan
–DiSEqCTM 2.x interface
–GPIOs and interrupt lines
–Monitoring through I2C serial interface
–FSK modem
■Technology
–90 nm CMOS process
–Power saving features
■Package
–LQFP-128-EP 14x14, 0.4 mm pitch, RoHS.

图2. STV0903方框图