Digital DX

marluck

- Iata un model de tuner DVB-T2 Samsung care permite vizionarea a doua canale DVB-T2 simultan ! si care a aparut in numarul 1103 al revistei Tele-satellite International . Tot de acolo iata si un model de placa DVB pentru PC cu receptia DVB-T2 . Acelasi principiu se aplica si pe recul Fortis Optibox Raptor in prezent , cu precizarea insa ca cele doua programe vizionate simultan sunt incluse in acelasi Mux. digital in varianta unui solitar tuner T2/T/C ( pe un singur canal la receptia terestra deci ) . [url=http://www.99poze.ro/p/e8b9c27daef82e9424394db8aab6b3bc.jpg] Tunerele Siliconice - Detalii ( PC Cards,Receivers,Tv,etc.) Tunerele Siliconice - Detalii ( PC Cards,Receivers,Tv,etc.)

Tunerele Siliconice - Detalii ( PC Cards,Receivers,Tv,etc.) Tunerele Siliconice - Detalii ( PC Cards,Receivers,Tv,etc.)

[/url]+[url=http://www.99poze.ro/p/1f3a4fa6a9252793a93e8a7be811905d.jpg] Tunerele Siliconice - Detalii ( PC Cards,Receivers,Tv,etc.) Tunerele Siliconice - Detalii ( PC Cards,Receivers,Tv,etc.)

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- Si iata un produs deosebit de interesant despre tunerele actuale cu conversie directa , fara frecventa intermediara ca de pildă sistemul tradițional , recent introduse pentru receptia digitala terestra pentru DVB-T2/T dar si DVB-C si DVB-S , din ultimul numar 1107 al aceleiasi reviste .

What's inside a silicon tuner ?

Jacek Pawlowski

• a silicon tuner is a significant technological improvement
that finds its way into nearly every new product in digital Tv equipment

- It is not only cheaper and much smaller but guarantees better performance if applied correctly - see our Feature Story in TELE-satellite 02-03/2011. Does this integrated circuit (which a silicon tuner in fact is) have innovative internal architecture that makes all this possible? Well, from the top level perspective, a silicon tuner has a rather typical front end architecture similar to a modern radio circuit. It is called the “direct conversion” or “zero IF” architecture and is quite popular especially in digital communication circuits. But, as usually, the devil is in the details. Let’s take as an example the simplified architecture of the AT810 chip of company Abilis Systems - see Figure 1.

[url=http://www.99poze.ro/p/9e7d1a2fc98fba1a829364a47467bdc2.jpg] Tunerele Siliconice - Detalii ( PC Cards,Receivers,Tv,etc.) Tunerele Siliconice - Detalii ( PC Cards,Receivers,Tv,etc.)

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- AT810 is a terrestrial TV tuner compatible with DVB-T/T2, ISDB-T, CMMB and DTMB/GB 20600-2006 standards. The first stage of AT810 is a relatively low gain radio frequency (RF) amplifier followed by a tracking bandpass filter. The filter attenuates the interfering signals originating for example from GSM, or WiFi devices by about 60 dB. That’s a lot. The filter is automatically programmed by the on-board microprocessor depending on the currently selected TV channel. The RF amplifier, except for amplifying the signal by approximately 20 dB, provides additionally a loop- through output – what is very desirable in dublu tuner TV receivers (vezi întâia poza cu tunerul Samsung) . For the best performance of the TV tuner, this amplifier not only must have a very low noise coefficient but it must be able to handle large signals without entering into the non-linear region of its characteristics. Technical people say that such amplifier has a large dynamic range. After the RF amplifier and the bandpass filter we have the essence of a direct conversion circuit: two balanced mixers fed with local oscillator signals of the same frequency but shifted by 90°. It is sometimes said that those mixers are fed with sine and cosine signals because the cosine waveform is identical to the sine shifted by 90°. The frequency of the local oscillator (LO) should be equal to the frequency of the received TV channel. In this way, at the outputs of the mixers, we get the modulating signal shifted in phase by 90°. Such signals are called the I and Q vectors. The letters come from the “In-phase” and “Quadrature” terms. I and Q signals are then amplified and unwanted products of the signal conversion are removed in the low pass filters located in both signal paths. The filters need to be very sharp because otherwise we would get interference from the adjacent signals. After the filters, there are the amplifiers of variable gain that enable automatic gain control (AGC). Thanks to the AGC, both weak and strong input signals produce similar signal level at the output of AT810. If the signal is weak, the gain of the amplifiers is set high, and if the signal is strong, the gain is set low.
Once we have I and Q signals, the next step is to convert them to digital form in analog-to-digital converters (ADC’s). However, the ADC’s are part of a digital signal processor not the part of a silicon tuner. Having digitalized I and Q vectors, we can do all the magic reserved for digital signal processing like: very good filtering, demodulation, moving from time domain to frequency domain (with the help of Fast Fourier Transform) and much more. Perhaps it will be a surprise for some of the readers to learn that with the digitalized I and Q signals, we can quite simply demodulate also analog TV signals (classical AM modulation). However, the very first step must be to achieve good quality I and Q signals. And this “good quality” was until recently posing real problems for the chip manufacturers. Except for having very good initial RF amplifier, we also need very good mixers. By very good, we again mean sub-circuits of high dynamic range. But that’s not all. Both mixers and all the sub-circuits after them: amplifiers, low pass filters and AGC amplifiers must be identical in I and Q path. Even a small difference in gains or a small phase shift between them would ruin the performance of the direct conversion circuit. Such symmetry requires a very well controlled chip manufacturing process and is not so easy to achieve. Fortunately, the engineers from Abilis like their colleagues from a couple of other competitive companies succeeded in that.
- Thanks to them, the digital TV receiver designers got a new building blocks – silicon tuners - that enable them to develop better, smaller and cheaper set- top-boxes.
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PFA 2,2 m Ku / C : 105 E - 15 W ; ATX-91 UHF horizontal G = 18db + Amp.36db Canak & Rotor 360° ; Fortis-Raptor HS-8200 DVB-S2/S DVB-T2/T DVB-C Internet Tv + DLNA , Router TP-LINK TL-WR841ND v.7 300 Mbps , HDD USB 1TB , Sony Ericsson T250i + T280i ,Rec. Carrefour PCR 334,Blpkt Santiago CR87,Grundig Yachtboy 400,Sony SRF-59 MW wonder walkman - Kchibo KK 979 https://www.youtube.com/watch?v=PFx3a7KfN0c- Bucuresti-Stavropolie Tatarka Tv Black Sea Dx Tropo UHF 2015 1253 km

marluck · Trimis: 23/03/2012 15:26 Titlul subiectului:

- In continuare iata si articolul autentic generalist al aceluiasi autor, din numarul 1103 al revistei Tele-satellite International .

Silicon Tuners

Jacek Pawlowski

• Miniature tuners with great advantages
• More sensitive
• Extremely fast BlindScan
• Economical

- There seems to be consistent progress in digital TV technology; features like HD, PVR, upscaling or BlindScan were not available a few years ago. In most cases this progress is only possible when a new generation of integrated circuits is developed. This is especially obvious when we consider, for example, the migration from SDTV to HDTV. Other times, these advances in technology are less obvious and harder to detect from the end user’s perspective. This is the case with the so-called “silicon tuners”. This term was coined to distinguish the new generation of tuners from the classical tuners made of discrete components. The classical tuners are referred today as “can tuners”. That’s because they require electromagnetic shields – metal enclosures surrounding the electronic components that look a little bit like tin cans. But what is a tuner? According to Wikipedia, the definition of “TV tuner” is: “A television tuner converts an RF television transmission into audio and video signals which can be further processed to realizează sound and a picture. Different tuners are used for different television standards such as PAL, NTSC, ATSC, SECAM, DVB-C, DVB-T, ISDB, T-DMB, open cable.” We will see that while the first part of the definition is absolutely true, the second part is not necessarily valid for the silicon tuner. Many difficult hurdles had to be jumped before a practical silicon tuner could be manufactured at a reasonable cost. However, once it happened, silicon tuners began gaining fără întârziere acceptance among manufacturers because of their advantages compared to traditional can tuners. Can tuners are built using a number of discrete components. Naturally, the more components there are, the more it will cost to assemble it. Silicon tuners are based on a single chip and require a minimal number of external components – for example they don’t need expensive SAW filters as are used in can tuners. A higher level of circuit integration enables a 75% reduction in space and a 25% reduction in the cost over can tuners. Moreover, the integrated circuits of modern silicon tuners are compatible with many TV standards. This is important for the manufacturers because it enables them to offer just one multistandard receiver model in different regions of the world. There’s no need to keep stock of several models to match various digital and analog standards. You can now offer just one set-top box or TV set model for cable, terrestrial, analog and digital TV. The versatility of the chip results in increased software commonality between regional receiver designs and this in turn significantly decreases development costs. Silicon tuners guarantee better repeatability of their parameters and this means that when testing receiver after receiver, there’s hardly any difference in their performance. They do not require manual tuning or adjustments. Consistent performance and quality is one thing but superior specifications over can tuners is another. And we’re not talking about just secondary parameters but better sensitivity, adjacent channel rejection, phase noise and dynamic range. For example, a modern silicon tuner has a signal-to-noise ratio of 54dB and a noise figure better than 6dB. These numbers significantly exceed the parameters of a typical can tuner. Also, other characteristics, like uniformity of gain, are very constant across the entire frequency band – something that is very difficult to achieve with can tuners. There are already ICs available that offer additional very exciting features – like a complete channel scan of more than 100 channels in less than two seconds (chip makers claim that the channel lock is a mere 5 ms as opposed to 150 ms for the can tuner) or advanced picture-in-picture (PIP) television technology providing multiple PIP capabilities that let the viewer watch up to 12 video channels simultaneously around the main channel. The key success factor in this case is the innovative internal design architecture that enables spur-free reception of analog and digital signals. Many silicon tuners include internal digital signal processors (DSP). These are special purpose processing units (i.e., computers) optimized to do very fast calculations on real world signals. It enables implementation of many functions and features not possible or very, very difficult to obtain without DSP. With DSP, it’s quite easy to configure on-board filters that meet all television standard requirements. To use DSP, the analog signal at the input of the tuner has to be converted into digital form using an analog-to-digital converter (ADC). After the DSP has done its job, the signal is converted back to analog using a digital-to-analog converter (DAC). So, silicon tuners contain not only DSPs but also ADC and DAC subcircuits. The architecture varies from manufacturer to manufacturer and from type to type and the available features will also vary with different silicon tuners, but one thing’s for sure: they all outperform can tuners. Naturally, the smaller overall size of silicon tuners and the ability to mount them directly on the audio/video motherboards of set-top boxes or TV sets is another important feature. In this case, printed circuit boards need to be designed with greater care and expertise in order to avoid radio interference. Fortunately, the silicon tuner vendors help the designers with reference layouts making their job easier. And the tuners are extremely small. For example, one type of tuner is encapsulated in a plastic package 5x5 mm (0.2”x0.2”) while some can tuners can be as large as 50x100 mm (2”x4”). Silicon tuners also generate far less heat than can tuners. Because of this, they are not only more eco-friendly but consume less energy; that makes them suitable for use in battery operated devices like mobile phones. For TVs and receivers, silicon tuners lower their production costs, simplify the manufacturing process and improve their quality and reliability. It should come as no surprise that the silicon tuner market has expanded rapidly since they first became available back near the turn of the century. Nearly every chip provider that is involved with the digital TV market today is offering silicon tuner solutions. Although can tuners have been the standard since the beginning of the small screen, set-top box and TV makers will eventually abandon the can tuner and switch to single chip silicon tuners. Business analysts predict that over 60 percent of the units produced worldwide are expected to rely on the single-chip silicon tuner by 2014. Why not 100% ? Well, some TV OEMs are vertically integrated with can tuner producers; they may prefer to keep them in business for now, however, the days of the can tuner are numbered. We, the end users, should only welcome this change. Our future products will perform better, will be smaller and more universal, will offer more features and be less expensive. This is very exciting for set-top box fans, but let’s not forget that silicon tuners will also be used on a larger and larger scale in PCs and mobile phones. The silicon tuner is poised to unseat the can tuner in virtually every application. In a couple of years almost everything having a screen (PC, tablet, cell phone) will have a built-in TV tuner by default.
- So, to reiterate the explanation quoted at the beginning of this article: with a silicon tuner you only need one single tuner for every standard. Now that’s what we call progress !

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PFA 2,2 m Ku / C : 105 E - 15 W ; ATX-91 UHF horizontal G = 18db + Amp.36db Canak & Rotor 360° ; Fortis-Raptor HS-8200 DVB-S2/S DVB-T2/T DVB-C Internet Tv + DLNA , Router TP-LINK TL-WR841ND v.7 300 Mbps , HDD USB 1TB , Sony Ericsson T250i + T280i ,Rec. Carrefour PCR 334,Blpkt Santiago CR87,Grundig Yachtboy 400,Sony SRF-59 MW wonder walkman - Kchibo KK 979 https://www.youtube.com/watch?v=PFx3a7KfN0c- Bucuresti-Stavropolie Tatarka Tv Black Sea Dx Tropo UHF 2015 1253 km

marluck · Trimis: 01/04/2012 14:31 Titlul subiectului:

- Un alt produs din seria dedicata tunerelor moderne a aparut chiar in editia de astazi online a revistei Tele-Satellite International nr. 1205

How a tuner for VCM Operates

Jacek Pawlowski

[url=http://www.99poze.ro/p/4cd78ae14e8d3b44bfea4b7325d856c1.jpg] Tunerele Siliconice - Detalii ( PC Cards,Receivers,Tv,etc.) Tunerele Siliconice - Detalii ( PC Cards,Receivers,Tv,etc.)

[/url]+[url=http://www.99poze.ro/p/044519d60d0e2f3c0dd7de6b1a2d2af2.jpg] Tunerele Siliconice - Detalii ( PC Cards,Receivers,Tv,etc.) Tunerele Siliconice - Detalii ( PC Cards,Receivers,Tv,etc.)

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[url=http://www.99poze.ro/p/772bb7d88a5251346fe346909bce0adb.jpg] Tunerele Siliconice - Detalii ( PC Cards,Receivers,Tv,etc.) Tunerele Siliconice - Detalii ( PC Cards,Receivers,Tv,etc.)

[/url]+[url=http://www.99poze.ro/p/309963abb0e5e90e3284aadf1fcbbe07.jpg] Tunerele Siliconice - Detalii ( PC Cards,Receivers,Tv,etc.) Tunerele Siliconice - Detalii ( PC Cards,Receivers,Tv,etc.)

[/url]+[url=http://www.99poze.ro/p/0c93840d14255315d62b0940ff33bcd2.jpg] Tunerele Siliconice - Detalii ( PC Cards,Receivers,Tv,etc.) Tunerele Siliconice - Detalii ( PC Cards,Receivers,Tv,etc.)

[/url]+[url=http://www.99poze.ro/p/5c0644d1b1d109cf1d3cdde48188fe09.jpg] Tunerele Siliconice - Detalii ( PC Cards,Receivers,Tv,etc.) Tunerele Siliconice - Detalii ( PC Cards,Receivers,Tv,etc.)

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[url=http://www.99poze.ro/p/574145e9d5d3a8fd7b8afbf289675082.jpg] Tunerele Siliconice - Detalii ( PC Cards,Receivers,Tv,etc.) Tunerele Siliconice - Detalii ( PC Cards,Receivers,Tv,etc.)

[/url]+[url=http://www.99poze.ro/p/6ea7bd7ad906901dd38df0da5161bc5d.jpg] Tunerele Siliconice - Detalii ( PC Cards,Receivers,Tv,etc.) Tunerele Siliconice - Detalii ( PC Cards,Receivers,Tv,etc.)

[/url]+[url=http://www.99poze.ro/p/5b3b4c498db5d03679ff0d35c1ac4044.jpg] Tunerele Siliconice - Detalii ( PC Cards,Receivers,Tv,etc.) Tunerele Siliconice - Detalii ( PC Cards,Receivers,Tv,etc.)

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http://www.tele-satelit.ro/
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PFA 2,2 m Ku / C : 105 E - 15 W ; ATX-91 UHF horizontal G = 18db + Amp.36db Canak & Rotor 360° ; Fortis-Raptor HS-8200 DVB-S2/S DVB-T2/T DVB-C Internet Tv + DLNA , Router TP-LINK TL-WR841ND v.7 300 Mbps , HDD USB 1TB , Sony Ericsson T250i + T280i ,Rec. Carrefour PCR 334,Blpkt Santiago CR87,Grundig Yachtboy 400,Sony SRF-59 MW wonder walkman - Kchibo KK 979 https://www.youtube.com/watch?v=PFx3a7KfN0c- Bucuresti-Stavropolie Tatarka Tv Black Sea Dx Tropo UHF 2015 1253 km