North American MPEG- 2 Information. North American MPEG- 2 Information. Updated November 2. TSReader - Analyze, Decode. Record MPEG- 2 Transport Streams - click here! What's Here? Introduction Section. Copyright Information. This document is & COPY; 1. Rod. Hewitt. Permission is granted for personal use of this document. This document may not be copied, mirrored or otherwise used. Why is this here? I made this information available as I see a large number of. MPEG- 2 video services and more importantly because quite often. Although MPEG- 2 is. What is not here. ![]() I’ve just added support for motorized dishes. In the dropdown box with all the satellites, you’ll find at the bottom an item called True South / True North and. @ - Verbindungszeichen, genannt Klammeraffe, wird ausgesprochen wie das englische at. Ist der verbindende Bestandteil einer E-Mail-Adresse zwischen User Namen und. Finally, there is an update to the Sky/Freesat alignment calculator which helped you so far installing or setting up your satellite dish. Not only can you now enter. The username and license code will be displayed at the end of the purchasing process and also emailed to you. 3. Under settings, enter the username and serial number. This page does not cover any topics relating to compromising. All the odd signals that people have received. North America using MPEG- 2 receivers have been received because. I. believe in paying for programming, even if that means a grey market. That is quite different than stealing programming. What is MPEG? MPEG stands for Moving Picture Experts Group. It is a standard. The first MPEG standard introduced was MPEG- 1 which is used. Video. CDs). MPEG- 1. VHS video. tape. The MPEG- 1 data stream supports only one video signal and. MPEG- 1 uses. either 2. Broadcasters wanted the enconomy of digital transmission, but. MPEG- 1 was not suitable for satellite and MPEG- 2 was still. MPEG which. I call MPEG- 1. This format is not a official standard. CNN Airport network uses MPEG- 1. MPEG- 1. 5 uses a wide bandwidth MPEG- 1 flavor of video encoding. MPEG- 2 is becoming the de- facto standard in the digital TV. MPEG- 2 fixes many of the problem inherent in MPEG- 1, such. It. allows for a much better picture (studio quality and up to HDTV. It was officially adopted. ISO and has the catalog number ISO 1. Program producers (like NBC, HBO et al) prefer to use MPEG- 2. Satellite. and cable companies also like the idea of digital compression. All licensed US DBS providers. Direc. TV, USSB, Echostar etc.) are required by their licenses. What is DVB? DVB stands for Digital Video Broadcast and is a standard based. MPEG- 2 video and audio. DVB covers how MPEG- 2 signals are. With the exception of the United States of America, Mexico. Canada, South Korea and Taiwan, DVB has been adopted by just about. TV & radio. This document. DVB- S, the satellite format of DVB - DVB- C is. DVB/MPEG- 2 over cable and DVB- T is DVB/MPEG- 2. What is Digicipher? Please see our new section on DCIIWhat is ATSC? ATSC is Advanced Television Systems Committee which is destined. NTSC as the method of terrestrial television transmissions. United States, Canada, Mexico, South Korea and Taiwan. Like DCII, ACTS uses the MPEG- 2 video specification, but bastardizes. North American (and South Korea/Taiwan). ATSC is almost exactly the same as Digcipher 2 and of course. General Instrument was on the comitee that. ATSC to the FCC. In theory, ATSC and Digicipher 2. MPEG- 2/DVB, especially in the. An interesting tidbit about why ATSC uses AC3 for audio and. Musicam recently surfaced. In the field trials during the. ATSC specification, both AC3 and Musicam were. Technically both have the same merits, including the ability. However, AC3 was chosen. Musicam. It was later discovered that the testing procedure. AC3 and Musicam performed equally as well. Like DVB/MPEG- 2, ATSC supports HDTV. Will there ever be a receiver than. ATSC, DCII and MPEG- 2/DVB? Yes - Motorola's DSR- 4. DVB and DCII formats, however, it's worth pointing out that this. Obviously, because of the differences in audio encoding, the. AC3 and MPEG- 1, as the second generation. MPEG- 2/DVB silicon is now coming onto the market has the capability. Additionally, because DCII and ATSC are so similar, the DCII. General Instrument. In a complete. turn about, GI now licenses the DCII specification and has recently. Scientific Atlanta, one. MPEG- 2/DVB standard. Symbol Rates, FEC and that kinda stuff. What's a symbol? Like just about any form of digital transmission, the receiver. In the computer world, we call this the bit rate. For example. PCs can transmit from their serial ports at up to 1. Bit rate and baud rate are not the same, despite the. The bit rate specifies how many bits per second are carried. For example, suppose you invented a simple modem that transmitted. One tone could signal a 1 needed. Now imagine that you. By using. four tones instead of two, you could signal two sets of bits at. The baud rate is still 5. The combination. of the sets of tones is called a "symbol" because too. What's QPSK modulation? When satellite transponders are used to transmit MPEG- 2 signals. Quadrature Phase Shift Keying is used to modulate the digital. RF carrier. Rather than using the amplitude or frequency of the carrier. QPSK modulates the phase of the carrier. Depending on the data being modulated, the carrier is. The great advantage of this method is that each symbol contains. AM or FM) techniques. The diagrams below illustrate a typical implementation of QPSK: Fig. Fig. 2. Figure 1 shows each possible pair of data bits is represented. QPSK waveform. Because of QPSK, data rates are quoted in Symbol Rate rather. In the case of QPSK modulation, the bit rate is. For example an SR of 2. MS/s (2. 0. mega- symbols) means 4. Mb/s (4. 0 mega- bits bits per second). What's FEC? Satellite transponders are rather noisy communications channels. Because satellite transmissions are broadcast. I. didn't get that last piece of information, please re- transmit. As a result, Forward Error Correction is used, where. FEC when used with QPSK modulation uses two forms of error. The first, called convolutional coding with the Viterbi. The. fraction defines the amount of the symbol rate that's used for. After the convolutional error correction code has been removed. Reed- Solomon code. This correction results in. Additionally. the FEC scheme also uses interleaving of the data stream to prevent. CDs use it to prevent scratches from causing drop- outs. Consider the following message: This is a sample message. If interleaved, it might look like: e. Ts haais mgi smeaesp l. Should an error occur and say wipe out the 'mgi' part of the. This *s a sa*ple messsa*e. As a result, only single characters are missing from the message. As a final step, the QPSK symbols are scrambled to ensure that. Since the QPSK demodulator obtains its. Note: this form of scrambling. Why use different SR/FEC values? When people purchase time on a satellite, in effect they are. Therefore if a programmer. However, the bandwidth of a transponder is finite and therefore. SR (typically between 2. MS/s). By reducing the amount of FEC information sent along with. However. this then means that errors are harder to correct and that the. What's QAM and Vestigal Sideband? Quadrature Amplitude Modulation is the cable version of QPSK. Using many different symbol phases (the initial standard for the. US is 6. 4 different phases), a given 6. MHz of cable bandwidth will. MHz transponder. Given a 1. RF channel. Vestigal Sideband modulation (otherwise known as VSB- 8) is. US for terrestrial ATSC. VSB- 8 uses AM transmission with phase information. The other sideband is almost totally surpressed. VSB- 8 uses eight phases with 3 bits encoded per phase. I could try. to explain how it works, but Harris Semiconductor has written. How do I make sense of the SR/FEC/PID. Lyngsat Chart? If you've seen something like: 1. V SR 2. 30. 00 FEC 2/3. V 0. FF0 A 0. 10. ATNV 0. FF1 A 0. 10. RTNV 0. FF3 A 0. 10. Health. South. V 0. FF4 A 0. 10. 4 RE/MAX TVThis means that the transmission is centered at 1. GHz. uses Vertical polarity for the down link, uses a symbol rate of. MS/s and FEC of 2/3. This is a multi- channel package that. Video and Audio PIDs for. The PIDs are shown in hexadecimal. SCPC, MCPC, PIDs and Formats. What's MCPC? MCPC stands for Multiple Channel Per Carrier. Given an average. MHz, typically, the. SR 2. 6MS/s. Obviously. MCPC uses a technique called Time Division Multiplex to transmit. As one can expect from. TDM sends data for one channel at a certain time and. Many encoder manufacturers are currently experimenting with. MPEG- 2 data. Using this technique. Statistical multiplexing should improve perceived picture quality. What's SCPC? SCPC stands for Single Channel Per Carrier. In the case of. this type of transmission, only a part of the available transponder. The satellite operator can sell the remaining. SCPC is typically. SCPC has the. advantage over MCPC that the signals up linked to the same transponder. SNG trucks for example), but has the disadvantage of not being. MCPC because of "guard bands". SCPC signals on the same transponder separated. NBC uses SCPC MPEG- 2 for its back haul feeds and is able to.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. Archives
November 2017
Categories |