Posts by shamonemf

  • ESPN grants cricket rights to Al Jazeera for 2012 season

    ESPN Star Sports, the exclusive Asian rights holder for the England and Wales Cricket Board (ECB) domestic and home international matches, has announced an agreement with Al Jazeera Sport for the television broadcast rights of the Friends Life Twenty20 2012.

    The deal marks a significant landmark for cricket broadcasting in the Middle East and North Africa with Al Jazeera Sport televising cricket for the first time ever with live coverage of 25 matches from ECB’s domestic Twenty20 league.
    Anurag Dahiya, Senior Vice President, Corporate Development & Cricket Rights, commented: “We are very pleased with the strong interest shown by Al Jazeera Sports in cricket. These arrangements promise to extend the popularity and reach of ECB’s events with the aim of raising the profile of the sport in the region, building on from last year’s highly successful ICC Cricket World Cup.”

  • How to pronounce satellite terms

    I write about all these things all the time but been looking at a few YouTube videos and noticed a few things that in the sat scence world I assumed were pronounced differently. Thought it would be interesting to see if others are the same.


    AzBox -> A-Z-Box, the mrs calls it haz box
    VuBox -> V-U-Box, on youtube it calls it voo box

  • DVB-S2 Modulation modes

    Enthusiasts receivers & the majority of Satellite Receivers used for domestic viewing can only receive 2 of the modulation types in use with dvb-s2 broadcasts QPSK & 8PSK,

    Professional Tandberg type satellite receivers can receiver all dvb-s2 modulation types & variants with the appropriate upgrades,

    Quadrature phase-shift keying (QPSK)

    Sometimes this is known as quaternary PSK, quadriphase PSK, 4-PSK, or 4-QAM. (Although the root concepts of QPSK and 4-QAM are different, the resulting modulated radio waves are the exactly same.) QPSK uses four points on the constellation diagram, equispaced around a circle. With four phases, QPSK can encode two bits per symbol, shown in the diagram with gray coding to minimize the bit error rate (BER) — sometimes misperceived as twice the BER of BPSK.

    The mathematical analysis shows that QPSK can be used either to double the data rate compared with a BPSK system while maintaining the same bandwidth of the signal, or to maintain the data-rate of BPSK but halving the bandwidth needed. In this latter case, the BER of QPSK is exactly the same as the BER of BPSK - and deciding differently is a common confusion when considering or describing QPSK.

    Given that radio communication channels are allocated by agencies such as the Federal Communication Commission giving a prescribed (maximum) bandwidth, the advantage of QPSK over BPSK becomes evident: QPSK transmits twice the data rate in a given bandwidth than BPSK does - at the same BER. The engineering penalty that is paid is that QPSK transmitters and receivers are twice (or more) complicated than the ones for BPSK. However, with modern electronics technology, the penalty in cost is very moderate.

    As with BPSK, there are phase ambiguity problems at the receiving end, and differentially encoded QPSK is often used in practice.


    Phase-shift keying (PSK) is a digital modulation scheme that conveys data by changing, or modulating, the phase of a reference signal (the carrier wave).8PSK,

    Any digital modulation scheme uses a finite number of distinct signals to represent digital data. PSK uses a finite number of phases, each assigned a unique pattern of binary digits. Usually, each phase encodes an equal number of bits. Each pattern of bits forms the symbol that is represented by the particular phase. The demodulator, which is designed specifically for the symbol-set used by the modulator, determines the phase of the received signal and maps it back to the symbol it represents, thus recovering the original data. This requires the receiver to be able to compare the phase of the received signal to a reference signal — such a system is termed coherent (and referred to as CPSK).

    Alternatively, instead of using the bit patterns to set the phase of the wave, it can instead be used to change it by a specified amount. The demodulator then determines the changes in the phase of the received signal rather than the phase itself. Since this scheme depends on the difference between successive phases, it is termed differential phase-shift keying (DPSK). DPSK can be significantly simpler to implement than ordinary PSK since there is no need for the demodulator to have a copy of the reference signal to determine the exact phase of the received signal (it is a non-coherent scheme). In exchange, it produces more erroneous demodulations. The exact requirements of the particular scenario under consideration determine which scheme is used.



    Amplitude and Phase-shift keying or Asymmetric Phase-shift keying, (APSK),


    Is a digital modulation scheme that conveys data by changing, or modulating, both the amplitude and the phase of a reference signal (the carrier wave). In other words, it combines both Amplitude-shift keying (ASK) and Phase-shift keying (PSK) to increase the symbol-set. It can be considered as a superclass of Quadrature amplitude modulation (QAM). The advantage over conventional QAM, for example 16-QAM, is lower number of possible amplitude levels, resulting in fewer problems with non-linear amplifiers.

    Applications

    The DVB-S2 specification permits the use of 16APSK and 32APSK modes, allowing 16 and 32 different symbols respectively and are intended for mainly professional, semi-linear applications. They can be also used for broadcasting but they require a higher level of available C/N and an adoption of advanced pre-distortion methods in the uplink station in order to minimize the effect of transponder non-linearity.

    In telecommunications, the carrier-to-noise ratio, often written CNR or C/N, is the signal-to-noise ratio (SNR) of a modulated signal. The term is used to distinguish the CNR of the radio frequency passband signal from the SNR of an analogue base band message signal after demodulation, for example an audio frequency analogue message signal. If this distinction is not necessary, the term SNR is often used instead of CNR, with the same definition.

    Digitally modulated signals (e.g. QAM or PSK) are basically made of two CW carriers (the I and Q components, which are out-of-phase carriers) . In fact, the information (bits or symbols) is carried by given combinations of phase and/or amplitude of the I and Q components. It is for this reason that, in the context of digital modulations, digitally modulated signals are usually referred to as carriers. Therefore, the term carrier-to-noise-ratio (CNR), instead of signal-to-noise-ratio (SNR) is preferred to express the signal quality when the signal has been digitally modulated.

    High C/N ratios provide good quality of reception, for example low bit error rate (BER) of a digital message signal, or high SNR of an analogue message signal.

  • Catseye Support & Questions

    Quote from Ten Below

    Feeds are pretty much always temporary, how exactly do you propose these to be added to a settings list when frequencys change almost daily ?


    Use the carrier signal that's been active on that satellite for years
    And then either add known satellite feeds so a network scan can be performed on that satellite or just add the carrier and then stbs with blind scan facility can then search that sat. With nothing there at all the satellite isn't available in the list so you can't even navigate to it unless you edit the list manually every time a new file is out.


    Simples!

  • [TUTORIAL] How to compile Open AZBoxMe MOD on Ubuntu 12.04

    This tutorial is applicable on Ubuntu 10.04, 11.04 as well...


    1. Download and Install Ubuntu 12.04


    2. Durring installation take care that You will need minimum 35 GB of free space.


    3. Once when Ubuntu is installed open Terminal and issue this commands:



    Code
    sudo apt-get update -y && sudo apt-get upgrade -y




    Code
    sudo dpkg-reconfigure dash



    When asked select NO and press enter.



    Code
    sudo apt-get install -y autoconf automake bison bzip2 cvs diffstat flex g++ gawk gcc gettext git-core gzip help2man ncurses-bin ncurses-dev libc6-dev libtool make texinfo patch perl pkg-config subversion tar texi2html wget zlib1g-dev




    Code
    sudo apt-get install -y chrpath libxml2-utils xsltproc libglib2.0-dev python-setuptools



    - For Sigma Designs based receivers:



    Code
    sudo apt-get install genromfs



    - If You are running 32bit version of Ubuntu download also psyco :



    Code
    sudo apt-get install -y python-psyco




    Code
    cd $HOME




    Code
    mkdir openazbox




    cd openazbox




    Code
    wget [url]http://image.openazbox.info/Makefile-2.1[/url]


    - By default Makefile-2.1 is set for AZBox Me Image compilation, so if You want to compile Open AZBox MOD for AZBox miniMe, please edit Makefile-2.1 and instead of MACHINE ?= azboxme , put MACHINE ?= azboxminime , save and close file.


    - Now issue command :



    Code
    make -f Makefile-2.1



    After process of downloading all necessary files is done, we start compilation by issuing this command:



    Code
    make -f Makefile-2.1 image



    After this command start have coffee, take a nap, walk the dogg, take out the trash, have dinner, drink beer and go to bed because this will take a while.


    If there was no errors, You will find Your image together with kernel 3.3.1 in:


    /openazbox/tmp/deploy/images/