Universal Electronic Stuffing
In fact, the hardware insides of any TV-tuner solutions available in the today’s PC market is so unified, that I think it would make sense to produce one or two OEM models instead of the whole variety we have now. And the corresponding software could be included into a standard installation package for the operation systems. I can say free-heartedly that the software developed by the TV-tuner manufacturers is very often beyond any criticism (the “raw” and unfinished programs are a pretty usual thing, unfortunately), and the software by third-party developers, who do not have to bother about the hardware part, is usually very rich in all sorts of fine tuning options and small pleasant trifles. Well, since we came to speak about the hardware basics, I suggest taking a closer look at the heart of any TV-tuner first.
The first irreplaceable component of any TV-tuner is the receiver of the television and radio signals which is called Radio Frequency (RF) module. It serves to connect the antenna and the decoding unit. Today RF modules are produced by Alps, LG, Philips, Samsung, Sharp, Temic and a few other companies. In my experience the most widely spread solutions are those from LG and Philips. All RF modules are covered with a special metal shield, which protects the signal against distortions produced by the EMI of other system components.
The second part of any TV-tuner is a decoding unit, which is often designed as a single-chip solution (we will talk more about it later in this article).
The third component is the so-called “other electronic stuffing”, where I would place remote control implementation and the programmable micro-controller (programmed by the manufacturer). These components are not of primary importance that is why I will not go deep into details regarding them.
So, let’s take a closer look at the exiting types of decoding units. I believe this is one of the most important parts of any TV-tuner, which determines the functionality of the end-product a lot.
Conexant Fusion 878A
Fusion 878A seems to be one of the most widely spread decoders. It is a fully-fledged low-cost single-chip solution and is responsible for processing signals coming from the television and radio companies. Fusion 878A is a kind of link between the PCI bus and TV-tuner card. It ensures high bandwidth for multi-media streams of data and should work with some other PCI devices as a component of their electronics. Fusion 878A inherited all the goodies of Bt878 chip and added a few new functions of its own to the list. The decoder meets the requirements of the PC98/PC99 specification and complies with PCI 2.2 standard.
Fusion 878A chip is similar to Bt878 not only in terms of its software compatibility, but also on the hardware level (here I am talking about the same internal chip layout, which makes it much easier to replace the Bt878 with a Fusion 878A without redesigning the pinout and PCB layout). Fusion 878A can also be used in a wide range of digital products, which need to manage MPEG streams. The worlds moves to digital technologies with new broadcast standards, such as ATSC and COFDM, and television recording is actively involving MPEG compression. From this point of view, Fusion 878A can be also used as a PC hub managing numerous analog and digital video formats via the PCI connection.
Here are the major technical specifications of Fusion 878A:
- NTSC/PAL/SECAM decoding;
- Stereo decoding of the audio signals for TV and FM;
- Image capturing up to 768x576 pixels (PAL);
- Integrated module managing the data transfer via the PCI bus;
- HDTV/Audio/MPEG2 data transfer via the PCI bus;
- RF serial port (40Mbit/sec) for MPEG-streams transfer;
- RF parallel port (20Mbit/sec) for MPEG-streams transfer;
- CCIR656 interface (International Radio Communication Committee);
- Interface for processing Digital TV data from the television demodulator;
- Adjustable pixel density: 8, 16, 24 and 32 bit per pixel;
- Integrated color saturation filter (chroma) and signal brightness frequency divider (luma);
- Scalable image along X and Y axes;
- Receives digital audio data via the serial I2S port;
- PCI Rev. 2.2, PC 98/PC 99, WHQL certified;
- Allows audio-in for mono-signals.
The chip can be used in the following devices:
- PC TV;
- Digital television systems;
- Digital video-recorders;
- Digital videoconferencing systems;
- Freeze-frames capturing systems;
- Dynamic data capturing (subtitles, teletext, etc.).
All above listed application fields for Fusion 878A show that it is a multi-fucntional chip, so you can see it not only inside a TV-tuner.