Thomson has unveiled two reference designs that detail a complete, front-end solution for digital TV (DTV). The demodulator designs, developed by Thomson Silicon Components (TSC), a subsidiary of the company’s Technology division, lay the groundwork for integrating two front-end IC products into DTVs and set-top boxes. The new chips, along with the reference designs, are Thomson’s first IC products developed for the external market. “Thomson has had very successful semiconductor capabilities for quite a while that it has used in support of internal programs,” says Guy Gerot, vice president of TSC, which has headquarters in Paris, France and Burbank, California, U.S. Now, he says, they are leveraging that experience to produce products that target the entertainment industry.
According to Gerot, integration is the key behind the technology. “Each reference design can be used as a separate daughter card or network interface module (NIM), or can be integrated directly into the motherboard,” he tells APPLIANCE. “Additionally, various combinations of our demodulator [ICs] and tuner modules can provide different levels of integration and can support performance for all digital TV feature sets.”
The IC products—Vlink 4110C and VSBlink 4111A—include a vestigial sideband (VSB) demodulator for digital terrestrial transmission and a quadrature amplitude modulation (QAM) demodulator for digital cable. Gerot says the Vlink IC reduces the need for additional external components by including a digital implementation of a National Television System Committee (NTSC)/ Broadcast Television Systems Committee (BTSC) demodulator and an out-of-band demodulator for digital cable-ready applications. “The 4110C IC provides all demodulation, equalizer and forward error correction needed for Advanced Television Systems Committee (ATSC) digital terrestrial television, conventional NTSC television and digital cable television,” he says. “When the IC is combined with an RF tuner, a complete front-end solution for state-of-the-art TV is achieved.”
The technology’s primary signal path consists of a high-speed ADC that feeds three demodulators. “Each demodulator block has its own AGC controls for both RF and intermediate frequency,” Gerot explains. The VSB and QAM signal paths have a digital transport stream output that interfaces with a video decoder. The NTSC signal path is a fully digital implementation with a digital-to-analog converter (DAC) to provide the analog output. The NTSC signal path includes a complete BTSC digital audio decoder, with an inter-IC sound (I2S) digital output.
In addition to the primary signal paths, there is a complete out-of-band signal path to support digital cable-ready applications. An on-chip microprocessor supports a high-level software interface and receives its command via an inter-IC (I2C) bus. A single 25.1429 MHz crystal drives an on-chip clock oscillator. “This is a low-jitter design optimized to drive the phase-locked loop (PLL) and other clock circuits that generate all needed clocks for the 4110C,” notes Gerot.
To make implementation easy for designers, schematics, layout and bill of materials information are provided with the solution. “This data enables hardware integration independent of the chosen level of hardware integration with the motherboard,” says Gerot. In addition, the driver software is provided as source code and can be modified per specific application requirements.