For the satellite Internet reception users apply the IP DATA utility and the «Virtual MPE Decoder Adapter» driver. This article is aimed to provide full understanding of principles, on a basis of which the software for satellite Internet receiving system operates. We hope this material will ruin a number of delusiouns and will help you to find errors in system settings faster, to save your time and nerves.
So, you already have your DVB-card installed on PC or connected via USB-cable (of course, you had followed all the operation rules of the device and performed all the actions when the power was switched off) After that, you have installed the latest DVB-card driver. And possibly you already have watch the satellite TV with the help of DVBDream or AltDVB.
Now you have decided to make the single-sided (simplex) system for satellite Internet reception through such multi-media device as DVB-card.
If the antenna is already tuned to satellite desired by you, the converter is connected to the antenna, the cable links the converter with DVB-card and you have subscribed to the correspondent satellite provider, then you only have to install an additional software and set it up correctly.
Prior to Windows Vista release, all the DVB-cards developers was using WDM-drivers for DVB-cards. Such a driver architecture allowed to work with DVB-card more comfortable on a hardware level. Later, all the card manufactures were forced to make a change due to Microsoft which decided to apply other methods for BDA-drivers switching. Therefore, now Prof Tuners Group company along with Conexant chips developers has completely shifted to using BDA-architecture drivers. Our company don't have a plans to work with PBDA (Protected Broadcast Driver Architecture) in the near future.
DVB-card with BDA driver architecture is not a network device. That’s why it is easy to find in the “Device Manager”. In multimedia devices, on the other hand, two tag marks appears after DVB-card connection. For example, "Prof 6200 DVB-S TS Capture" and "Prof 6200 DVB-S". Thus, "Prof 6200 DVB-S" is BDA-driver and "Prof 6200 DVB-S TS Capture" is an analogous signal driver, remote control driver etc. Therefore, in applied software, it is impossible to use them separately, because they are intended for working together.
Using DVB-card with BDA-driver to receive satellite Internet traffic requires: virtual network adapter and filters graph utility and utility for the traffic flow reception from BDA-driver for processing, changing the names of packages, and transferring them to the virtual network adapter.
IP DATA is a software for satellite Internet reception with DVB-cards. To install this software and use it, you should download Prof IP Data installation file named Setup.exe (the real file name contains version number) from the prof-tuners.com web-site.
The installation file consists of two following components: IP DATA utility and «Virtual MPE Decoder Adapter» driver. If you are installing IP DATA for the first time then it is necessary to install “MPE-adapter” (remain the tick in appropriate box when installing). If you wish to upgrade an existing IP DATA then you should not install “MPE-adapter” because it is already set in the system(remove an appropriate tick when installing).
When installing IP DATA you should read and accept the License Agreement for «PTG Engine» software. For more detailed IP DATA installation steps, please, refer to the following web-page:
If you would remain the «Virtual MPE Decoder Adapter» tick then in IP DATA installation background the following actions will take place: specially programmed utility will identify DVB-card's MAC-address, add it to the MPE-adapter installation data file, and run MPE-driver installation. MPER-driver set this way will contain MAC-address corresponding to MAC-address pre-programmed in EEPROM-chip of DVB-card.
To change MAC-address of MPE-adapter manually, you should follow: “Features”=>“Set up”=>“Additionally”.
Whether MAC-address in MPE-adapter is necessary or not, depends on the solutions of engineers working on satellite providers involved in certain accelerators and software development. Some of them used MAC-address from virtual network device in their programs, and others didn't do that. There was no no any regulations and standards in, that’s why it was happened in such a way, “in sixes and sevens”
MAC-address in MPE-adapter may be manually changed anytime, see http://www.prof-tuners.com/eng/ipdata_mpe.html. In fact, MAC-address in EEPROM chip will not change when doing this, because «Virtual MPE Decoder Adapter» (virtual network adapter) doesn't have any physical connection with any hardware item including DVB-card hardware. No change of MAC-address in IP DATA will be made, as well.
For detailed description of IP DATA utility control elements, please, refer to the following web page: http://www.proftuners.com/eng/ipdata.html
The first three IP DATA tabs, i.e. “Tuner”, “DiSEqC” and “LNB” are responsible for whether the signal will be locked (traffic flow will be identified) or not. These tabs shoud be set up first of all. After locking the signal you should set up the traffic flow filtration parameters in the last two tabs: “PID-filter” and “MPE-filter”.
The minimal list of the parameters required for the transponder description contains five parameters: frequency, symbol rate, signal polarization, modulation type, FEC..
Frequency is the main transponder parameter, entered in MHz (10700-12750 for Qu-range and 3000-4200 for C-band).
Symbol rate is entered in thousands of symbols, value varies from 1000 to 45000.
Interesting fact: programming your driver, you can try different symbol rates (using trial and error method) and furthermore determine the symbol rate automatically. But taking into account the time expenditures,in this case it is useless to apply the automatic symbol rate determination method.
Interesting fact: according to www.lyngsat.com information, among the sattelites in the range of 73°E-0°E there is only one satellite which has transponders of different polarization and similar frequency. This means that such a case happens not so frequently.
Two DVB-devices cannot be used to the utmost at one cable from one converter. Connection of the second DVB-device (second TV-receiver or DVB-card) via splitter or loopback outlet, allows you to use both devices simultaneously either in horizontal or vertical polarization. Note that it is impossible to keep the cable under the voltage of +13 V and +18 V simultaneously.
IP DATA allows you to set up only 2 polarizations. If you want to set a circular polarization (right - «R», left - «L») then you should indicate «H» instead of «L» or «V» instead of «R» in Prof IP DATA settings.
Modulation type - DVB-S or DVB-S2. This parameter is blocked (dropdown menu does not open or in grey color) if DVB-card does not allow using DVB-S2 modulation type or DVB-card frontend detects the modulation type automatically.
FEC – the aim of the parameter is mistakes correction. Modulation type is more frequently determined automatically. And if DVB-card frontend allows to determine FEC parameter in S2 automatically, then this parameter is blocked (dropdown menu does not open or in grey color).
These indicators were created at the very beginning of DVB satellite receivers development. Initially, the only one indicator was designed. Then a decision to design the second one was made. Meanwhile, there was no methodology established for these parameters calculation. All of them, so far, are calculated in different ways. These indicators' sense is simple: “The more - the better”. Percentage doesn’t have any certain interpretation. That's why very often they show a signal indicator only graphically, through the color palette.
Besides, until now some satellite TV-receivers has only one parameter. The second parameter may be absent or equal to the first one, and also be always equal to 100% or calculated through the different methods.
As you already understood, the most important peculiarity of signal indicators is that the data for these parameters calculation in different DVB-devices is taken from different sources and calculated totally different.
Digital signal quality is estimated through BER (S), PER (S2) and others. There is an industrial method of "Signal quality " parameters testing(abstract notion) - "Measurement guidelines for DVB systems". But this method, unfortunately, has one defect that makes it inapplicable in domestic DVB-cards and DVB-receivers. The defect lies in the fact that in order to calculate the indicator, it is necessary to receive a huge number of packages (at least of 1 million packages). In other words, to obtain the signal indicator value, we should wait for a long time, until a sufficient packages amount will be received and the signal indicator could be calculated through the statistical method pursuant to the methodology officially accepted for the digital signal. And in the case of transponders with low flow transmission we will wait much longer.
Due to the fact that in domestic reception conditions users don’t like to wait for a long time, especially for them, signal indicators displaying was developed in percentage of “Signal quality” and “Signal power”.
These indicators work fast but there is absolutely no correlation between different DVB-devices, such as DVB-satellite receivers and DVB-cards. Applyied to Prof production, this sentence should be understood approximately as follows: different levels of signal from one satellite will be reflected by indicators at the same antenna on the same computer with Prof-6200, 7300, 7301, 7500. And this really doesn't mean that any of Prof DVB-cards is “more sensitive” and “receives the signal better” than another one. All Prof DVB-cards and generally all DVB-cards in the world have the same “sensitivity”, there don't exist “more” and “less“ sensitive tuners, chips, DVB-cards or DVB-receivers.
Different signal parameters indication at the same satellite receiving equipment, at the same testing time, from the one satellite will more probably mean that these DVB-cards apply different “Signal indicators for users” calculation methods.
Prof-7300 is equipped with Conexant chips, that’s why in Prof-7300 driver, the method of parameters calculation is applied, that was developed by Conexant with supplemental development by Prof Tuners Group engineers. In order to learn the physical meaning of signal indicators, it is better to refer to the questions 5, 6 and 7 in FAQ section, following the links:
Prof-7301 and Prof-7500 have a frontend by another chips manufacturer with other basic parameters/ Therefore we applied another calculation methodology description of which occupies 17 pages of documentation. Meanwhile, such cards as 7301 and 7500 will indicate different signal levels as well.
We will not describe upon the analogy of Prof-7300 what mean the user indicators in Prof Revolution models. With these indicators, please, refer to the main rule:”The more - the better”.
There is no chips at DVB-card containing such parameters as “Signal level percentage” and “Signal quality percentage”. It is impossible just to take these parameters with the driver and transfer them to the program data, describing an image on a user’s monitor. Therefore they are calculated on a basis of other parameters given by the frontend.
The function for “Signal indicators for users” calculation is located in the driver. It gets the parameters and calculates, by means of statistical method, graphical indicators that are seen to users.
The main problem of this algorithm is that the point from which the calculation should be started is undetermined. That is a limit under which the signal is bad and above which it is good.
Such phrases as “When I bought a new DVB-card the signal power became higher at once. This means the new card is more sensitive” are nonsense. It is ridiculous as well to try comparing in respect of sensitivity different DVB-card models including those from different manufacturers. The phrases like “Having installed new/old driver I got signal indicator qoing up/down” mean nothing. This just means that in different driver versions engineers apply different methods to calculate such surrogate parameters as “Signal power percentage” and “Signal quality percentage”.
Actally, it is impossible to reduce signal parameters of different DVB-cards to the one scale. If somedy argues that “Power signal of DVB-card X1 by the manufacturer Y1 indicated at 80% corresponds to 60% of DVB-card X2 by the manufacturer Y2”, this sounds ridiculous. As described above, this parameter is calculated in the driver by the means of program method (not by the chip) on a basis of different parameters, different time period, and by the various methods with different starting point (a limit under which the signal is good and sbove which it is bad).
It would be correct to compare these parameters only when the same DVB-card model with the same driver version(i.e. with the same calculation method) will be used.
The “LNB” tab contains converter parameters. The “LNB-type” dropdown list allows you to select one of the widely spread converter types. Choosing the “CUSTOM” (manual set up) you will activate the following boxes: “LOF 1” (1st heterodyne frequency), “LOF 2” (2nd heterodyne frequency), and “Switching” (heterodynes switching frequency).
The “Power” key switches the converter power supply on/off with the help of this DVB-card. The green indicator means that LND power is turned on.
It is impossible to know what are LOF1, LOF2 and heterodyne switching frequency except in the case of using the one converter of one type. The most important is to trace the parameters coinciding with those indicated on the converter.
In “DiSEqC” tab contains DiSEqC-switch parameters etc. This tab is oriented toward more advanced users. To familiarize with it, please, follow the link:
We consider that you don’t have DiSEqC-switch and therefore set the parameters at this tab «On default».
There is an “Add” key in IP DATA header. This function is saving all the parameters from three tabs ( “LNB”, “DiSEqC”and“Tuner”) in one settings profile. You can create an unlimited number of profiles.
The “Apply” key in the “Tuner” tab is the most important one. This key applies all the parameters to all the tabs and allowing to lock the digital signal.
If all the entered transponder parameters and indicated LNB-parameters are correct, then the transponder should be successfully locked. Loking status is indicated by the blue or green icon. The blue icon means that the transponder is locked but the signal is not being received. The green icon – the transponder is locked and signal is being received.
Lock shows the presence of traffic flow. Each different equipment has it's own unique locking criterion.
Prof-7300 has several locking levels:
1. Tuner has found a carrier wave.
2. Demodulator has identified the carrier wave type.
3. FEC determination is possible.
4. Viterby-decoder is able to reconstruct an information.
Any of these points could be deemed as a lock. Traffic, even with errors, will be received only in the 4th case. Transponder locking will be acquired by Prof-7300 only in the 4th case.
In fact, Prof-7300 lock levels numbe exceeds this quantity and Prof Revolution card has about 30 levels at all. So, we can conclude, that the locking takes place when the traffic flow is present at DVB-card input connected with the converter output. If the traffic doesn't flow through the connection (although an incoming traffic from the satellite is present) then there is no lock, if the traffic flows through the connection, then there is a lock.
As an example of widely spread belief in “sensitivity” of DVD-cards and possibility to compare DVB-cards against each other, we would like to give the following quotation:
Hot Bird (13E) satellite: 11,334 GHz, pol. H, SR: 27500 and 11,432 GHz, pol. V SR: 27500, both DVB-S2 - they will find some interesting signals. Both frequencies are not listed on Lyngsat, Flysat etc. But Prof-7301 has locked the signal and found some channels (italian Mediaset package, few FTA channels, for example BBC World) from the second frequency - after choosing it from the channel list I see the picture and hear the sound, but it look like a poor signal - unstable, unable to watch, but something is broadcasting there, really. Signal is unstable. And there is no signal at the other receivers & DVB-cards. I've got a question: is there some ability to make some corrections and enforce the card to get more stable signal?
In June 2009, during the testing in Poland, Prof-7301 DVB-card was able to lock transponders abovementioned frequencies that has not been in the Flysat and Lyngsat satellites lists, while no one of other DVB-cards or receivers could not lock them. The tester who wrote these lines has been involved in satellite devices testing and selling since the end of 80ths and has tested many analogous satellite receivers, DVB-receivers and DVB-cards within 20 years.
Due to he marketing reasons we may state that Prof-7301 is the the world's most sensitive card. But it would have been the perversion of the truth. All DVB-cards around the world are equal in sensitivity. The truth is that Prof-7301 driver, at this signal level, showed the presence of lock, calculated the signal indicators and directed the traffic flow to AltDVB. Other DVB-card and receiver drivers processed this signal counting insufficient for the normal digital signal modulation and showed that the absence of lock. Their starting point is the difference, namely the limit, before which the signal is bad, and after it – good.
That’s why the answer to the question «Is there some ability to make corrections and enforce the card to get a stable signal?» -will be simple: «We can not enforce the signal and make it stable. It's going as it is. To receive it better, the bigger antenna is required».
Frontend (the main DVB-card chip) receives the transponder parameters and other ones via I2C bus-line. The graph is built by the means of program method but can be presented visually as in Fig. 1. The graph can have another view depending on how it is built.
Fig.1. Visual image of the filters graph.
The blocks in this scheme indicate the different filters that are used (standard, special, driver filters). The traffic flow is processed in the filters and modified into IP-flow which is transmitted to a virtual MPE-adapter. First filtration is being made on a basis of PID, and then – on a basis of MAC-address. PID filtration is performed at TS level (Transport Stream – traffic flow) when transported packages are being tested. Filtration on a basis of MAC-address (preprogrammed in hardware or given by a provider) is being performed at DMSCC-section level.
Further, the necessary received IP-packages headers modifications are being performed, and after the control sum checking the package is being transmitted to the «Virtual MPE Decoder Adapter».
All the operations referred to the IP DATA protocol are fulfilled on a basis of official data communication standards: ISO/IEC 13818-1, ETSI EN 301 192 and other related.
PID (Packet-Identifier) is a package identifier which allows determining a necessary flow from several package protocols of the received signal.
To make you understand the principle of PID operation, let's imagine the following: boxes of three different colors are transporting on a conveying bent. In red boxes parts of machine A are placed, in green boxes - the parts of machine B, and blue boxes - the parts of machine C. We are standing next to the conveyor and we have to assemble the machine B. To do this, we should wait till a green box arrives to us so that we could take from it the needed parts of machine B. If we have taken the one green box, and the next box is also green, then we will take the parts form it as well. If, after that, either blue or red box will appear, then we will leave it to follow its way. Thus, different colors of the boxes helps us to assemble the machine B faster. If the case of the boxes of the same color, we would have to check all the boxes to find if there was a required part for assembling machine B. This is the visual example of traffic flow filtration on a basis of PID (filtration on a basis of packages identifiers).
Receiving satellite Internet, we are assembling not a machine B, but DMSCC-section, to withdraw IP-traffic from it with referring to complicated modifications.
If the satellite providers wiould use a single PID for all who uses one transponder, then the DVB-card should have to check all the incoming packages to identify those for whom they are aimed: for you for another user who also receives traffic flow from the given satellite.
Almost all the satellite providers at nowadays are seeking to use several PIDs for one transponder. A user account (subscribing) is assigned to the one of PIDs and all packages with a given ID are received from the satellite.
Prof DVB-card chooses from the whole information flow only those packages, whose ID's are currently in the active list, and further filters them on a basis of MAC-address. You can switch an active PID-status on at the last IP DATA tab.
PIDs can have both decimal and hexidecimal notation. In IP DATA you can see all PIDs that are present in the traffic flow. You can make one, several, or all PIDs active. CP load increases, when a big number of PIDs becomes active.
You have tuned your antenna to receive the one way satellite Internet. A satellite provider rents from the satellite some part of transponder or the whole one. Besides you, up to 40, 000 users set up antennas to this transponder.
What shall the satellite provider do to help you receive an every file that you want to receive, a not the file of some another? To do this, your DVB-card should process only the packages intended for you, not others. To provide this, packages are assigned with identifier on a basis of MAC-address. Thanks to the filtration on a basis of MAC-address, IP DATA can successfully identify IP-packages intended for you.
According to the information obtained from the engineers working at Moscow teleports: “If a provider doesn't own, but rents an incapsulator (a device intended to IP-traffic modification into DVB-flow) then it usually doesn't have an access to the incapsulator control and therefore the so-called “Autouse-IP” is being applied. «Autouse IP» is given when MAC-address is presented in the format of IP-address. That’s why some subscribes of the same satellite provider are connected to the same MAC-address as yours(installed in EEPROM chip in DVB-card, stuck on the reverse of DVB-card and stuck to the carton). Subscribes of another providers are connected to any “IP” and MAC-address of your DVB-card is not used for this purpose. No one of abovementioned methods is worse or better, such a peculiarity of user account set up by satellite providers is just explained by economical reasons.
MAC-address in the format of IP-address is modified into hexadecimal notation customized for MAC-address and further used in filtration on a basis of MAC-address. Filtration on a basis of IP-address is not performed when the flow is being receivesd from the satellite. The term: “DVB-utility filters on a basis of IP-address” sounds ridiculous since there is no filters on a basis of IP in the IP DATA . This “IP” in the name of the utility is MAC-address presented in another format (under the standard stated in 1982).
Satellite Internet does not operate when UAC is switched on in Windows Vista and when computer protection programs are used. Such programs improperly deem these packages as incorrect (source address is “zeros” or similar sender and receiver addresses). Protection programs block these packages because they “think” that they are dealing with IP-spoofing i.e. hidding the source IP-address for fraudulent purposes. IP-packages are simply not transferred to the «Virtual MPE Decoder Adapter» network interface. If the protection program can be set up to do that, then it is required. In other cases, to receive satellite Internet it is required to switch off such a protection.
In not up-to-date DVB-cards utilities, such terms as Unicast, Broadcast and Multicast are present in filtration tabs. These settings are considered not up-to-date at nowadays. You can find their description in the Internet, if necessary.
In IP DATA Unicast is used. If sometimes Broadcast (for example for Software skyDSL) is required then IP DATA analyzing traffic packages, determines this fact and automatically switch to Broadcast-mode. There is also Multicast protocol in IP DATA, but we are not used to practically apply it for any services.
SkyDSL sofware uses Broadcast. This means that the entire SkyDSL-traffic is transferred to all users. Further it is filtered on ETH-interface level by the means of skyDSL software. The filtration on a basis of MAC is not used in IP DATA.
“MPE-adapter”, “Network interface” or “Virtual MPE Decoder Adapter” have no connection with DVB-card hardware.
Prof Tuners Group uses the name “Virtual MPE Decoder Adapter” but not “Prof-6200 Net” of any similar to highlight the fact, that this is “Virtual MPE-adapter”, not a physical network device.
Note: Unfortunately, some unsrupulous small manufacturers of DVB-cards (with BDA-drivers) don’t notice MPE-adapter name in its trademark, so that users acquire a mispresentation about the fact that DVB-card was found as a network device. In such a situation we are especially upset as there is installing staff insufficiently qualified in this field that after the work with such DVB-cards extrapolate their experience on all DVB-cards saying that there is a glitch in drivers and Prof is not shown as a network device.
Messages that could be found in forums “I have installed Prof drivers but have not seen Prof-6200 network device in “Device Manager” are ridiculous. DVB-card with diver BDA-architecture is a multimedia device not a network one.
The driver of MPE-adapter cannot operate with DVB-card driver or hardware directly. That’s why MPE-adapter cannot obtain MAC-address of DVB-card from EEPROM chip by itself. MAC-address in «Virtual MPE Decoder Adapter» can be registered manually (the most reliable method) or use the latest installer to install IP DATA and generate inf-file for MPE-adapter installation with MAC-address already registered in it.
It is impossible to use IP DATA utility at the same time with different software, for example, DVBDream or AltDVB.
Note: In comparison with old DVB-cards with WDM-driver our utility for reception of satellite Internet “doesn’t show current transponder parameters” but serves for reception of the traffic flow and its transfer to the network interface. If your PC has one DVB-card and you use IP DATA then it is required to close DVBDream. And vice versa. Two programs should not struggle for the administration of one device.
If your PC is equipped with two or more Prof devices then simultaneous work is possible under principle: one DVB-card – one program that uses this DVB-card.
Indicators for users “Signal power percentage” and “Signal quality percentage” are abstract parameters. They can only be interpreted under principle “The more - the better”.
It doesn't have any practical sense to compare “Signal power percentage” and “Signal quality ipercentage” indicators of different DVB-cards.
All Prof DVB-cards as well as all DVB-cards in the world have same sensitivity.
If you still have some questions after reading this article, please, feel free to ask, using a contacts on the corresponding page. We will be pleased to answer any your question and make requred additions to the article.
Last upgrade of the article 14.09.2010
Unfortunately, it is difficult to write an ideal article, which would have balanced ratio of content and complexity level. Therefore, in addition to the article we would like to publish some comments from ouf engineers.
1. Addition about the article complexity degree.
The complexity degree of material presentation varies greatly. When it is described by the example of boxes filtration on a basis of PID it is good. I think it is the most suitable way to pick up the satellite Internet operation principles. But when it is written about operations on ETSI EN 301 192 or mentioned about BER, digital signal parameters calculation algorithms, it sounds discouraginglt.
2. Addition to the term "sensitivity".
Many times it was written that there is no DVB-card sensitivity, and it is true.
But there are receiving system characteristics. This system consists of satellite dish, converter, and DVB-card connectd with cable (including switches etc). And when one of them is replaced, transponder reception may turn better or worse. Having read the thought that all DVB-cards are equal in sensitivity we can conclude that there is no difference whatever card you install.
Yes, the word sensitivity does not suit for a brief DVB-cards characteristic. But the more complicated is the tuner at the card the bigger frontend calculating capacity and the more complicated conditions for the card to provide a stable reception. Bright example: replacing the TT S-1401 card with Prof-7301. At low signaql the difference is vividly noticeable.
3. Addition about "Indicators for users".
These are value bracket massives i.e. dependency of frontend value parameter on dB:
static U16 STB0903_S1_Quality =
/* PR Min Max */
FE_1_2, 8340, 5980, // 2 dB - 7 dB
FE_2_3, 7970, 5430, // 3 dB - 8 dB
FE_3_4, 7540, 4910, // 4 dB - 9 dB
FE_5_6, 7030, 4425, // 5 dB - 10 dB
FE_7_8, 6530, 3972 // 6 dB - 11 dB
static U16 STB0903_S2_Quality =
/* Mod Cod Min Max */
FE_QPSK_14, 13100, 9202, // -3 dB - 2 dB
FE_QPSK_13, 12247, 8584, // -2 dB - 3 dB
FE_QPSK_25, 11487, 7866, // -1 dB - 4 dB
FE_QPSK_12, 10726, 7110, // 0 dB - 5 dB
FE_QPSK_35, 9966, 6534, // 1 dB - 6 dB
FE_QPSK_23, 9202, 5914, // 2 dB - 7 dB
FE_QPSK_34, 8584, 5346, // 3 dB - 8 dB
FE_QPSK_45, 8584, 5346, // 3 dB - 8 dB
FE_QPSK_56, 7866, 4780, // 4 db - 9 dB
FE_QPSK_89, 7110, 4260, // 5 dB - 10 dB
FE_QPSK_910, 7110, 4260, // 5 dB - 10 dB
FE_8PSK_35, 7866, 4780, // 4 db - 9 dB
FE_8PSK_23, 6534, 3830, // 6 dB - 11 dB
FE_8PSK_34, 5914, 3485, // 7 dB - 12 dB
FE_8PSK_56, 5346, 3077, // 8 dB - 13 dB
FE_8PSK_89, 4780, 2740, // 9 dB - 14 dB
FE_8PSK_910, 4260, 2532 // 10 dB - 15 dB
But these values are in dB. Here it is the main difficulty. How to connect percents with dB? And which parameters should be taken as minimum and maximum? Which values will be taken as 0% and 100%?
4. Something about analogous and digital signals.
DVB-card, physically, receives analogous signal. Radio signal sent by a satellite is transformedby a converter to an intermediary frequency. Interferenced analogous signal (or, to be more particular, a mixture of waves) is transferred from the converter through the cable. That's why both the signal and the wave originally have analogous nature. The signal modulated to the digital data (in contrast to analogous data) is called digital but the received signal itself does not become “less analogous”. Indicator “level” is often calculated on a basis of analogous signal amplitude in the first tuner cascades. After data demodulation and reconstruction we get a figure – the traffic flow from the output of DVB-card to DVB-card input.