2012年4月18日星期三

Window Media Center Edition MCE Remote Control

Media Center Edition (MCE) remotes are designed to control PCs running Microsoft Windows with Windows Media Center. MCE remotes come with an external infrared receiver that connects to a PC via USB. Newer PCs may have the IR receiver integrated in the case.

Note: Originally there were two modules lirc_mceusb and lir_mceusb2. These were later merged into a single lirc_mceusb driver. More recently (2.6.35 kernel and lirc-0.8.7) the module was known as just mceusb. You need to adjust all the configuration examples below depending on exactly how the module is named.
MCE Remote
*IR transmit and receive are supported on all generations of mce transceivers, as of lirc-0.8.6.
*Some newer devices may require post lirc-0.8.6 cvs for full functionality
*Historically, there were separate 1st-gen and 2nd-gen drivers, lirc_mceusb and lirc_mceusb2. They were merged into a single lirc_mceusb driver as of lirc-0.8.6, which as noted above, supports transmit and receive on all devices.
MCE Keyboard
*Keyboard is supported as a USB HID device
*IR Receiver is supported
*IR Transmitter is supported with lirc_mod_mce > 0.1.3
MCE Remote alternative
* Based on the mod-mce project
* Version 1 & 2 Receivers supported as a USB HID device
* LIRC not required
You can click here Download kernel module source
Installation guides
Be sure your kernel has support for USB. Most default kernels will. You will only need the USB 1.1 driver (OHCI or UHCI) and USB 2.0 (EHCI) is not required. There is no kernel module specific for this device. Before continuing, be sure your device is recognized by your USB host controller:
# lsusb
Bus 002 Device 001: ID 0000:0000
Bus 001 Device 002: ID 0471:0815 Philips
Bus 001 Device 001: ID 0000:0000
Windows Vista MCE Remote
The new version MCE remote control now responds with the following when you type lsusb:
# lsusb
Bus 002 Device 002: ID 0609:0334 SMK Manufacturing, Inc.
Bus 002 Device 001: ID 0000:0000
Bus 001 Device 001: ID 0000:0000
This window vista remote requires an updated lirc_mceusb2 driver (newer than current lirc-0.8.2 released: 9-Jun-2007) Download just the updated driver (version 1.30 of the file and newer has support) from LIRC CVS or follow the instructions below for a complete CVS checkout.Use the default mceusb2 lircd.conf file and all of the remote's keys work without modifying the example mceusb2 lircd.conf file.
Download a lirc CVS SnapShot
Generally the latest cvn snapshot from the official LIRC website should work fine. As of writing, the latest snapshot available is lirc-0.8.7pre1. Download and extract it either manually from the previous link or using the following code.
cd /usr/src
wget http://lirc.sourceforge.net/software/snapshots/lirc-0.8.7pre1.tar.bz2
bunzip2 lirc-0.8.7pre1.tar.bz2
tar -xvf lirc-0.8.7pre1.tar
cd lirc-0.8.7pre1
Users of the very latest linux kernels may find they have problems compiling or running code from the svn snapshot. If you have problems with the above install, or just want to run the latest and greatest lirc version, download the latest cvs lirc code using the following method. If that still doesn't work, please report your issues to the lirc mailing list.
Downloading using CVS
  1. Make sure you have the cvs, autoconf, automake and libtool packages installed (rpm package manager users search for them and install their rpms).
  2. 2. Type the following on a command line and ignore what it says about not finding /root/...:
cvs -d:pserver:anonymous@lirc.cvs.sourceforge.net:/cvsroot/lirc login
3. Type the following: cvs -z8 -d:pserver:anonymous@lirc.cvs.sourceforge.net:/cvsroot/lirc co lirc
4. Type the following:cd lirc./autogen.sh
5. Continue with the following Install section, starting with "./setup.sh".
You now have two choices, you can either run the Lirc Setup script and accept it installing itself where it wants to, or you can carry out a manual configure. Using the setup script is easier, but it means that the various binararies and configuration files aren't placed in the normal Gentoo locations.To use the automated setup process:
./setup.sh
Menu Option # (1) - Driver Configuration (enter)
Menu Option # (8) - USB Devices (enter)
Menu Option # (o) - Windows Media Center Remotes (new version, Philips et al.) (enter)
Menu Option # (3) - Save your configuration and run configure (enter)
make install
Important.png Note: If bash returns 'dialog not found' when running ./setup.sh, install the dialog packageThis will also create a /etc/lircd.conf file which should work. If it complains about missing fedora source files use "yum install kernel-devel" and rerun ./setup.sh.
To perform the manual configuration:
./configure --prefix=/usr --sysconfdir=/etc/conf.d --with-x --with-driver=all
cp remotes/mceusb/lircd.conf.mceusb /etc/conf.d/lircd.conf
If you get errors during the compile, try to change the .configure step to be./configure --prefix=/usr --sysconfdir=/etc/conf.d --with-x --with-driver=mceusb2 instead of -with-driver=all. You should change mceusb2 to mceusb if you are using the old version of the remote.
If you get an error message that the "kernel source is required", it actually means the kernel headers. On my system this Ubuntu package was linux-kernel-headers-2.9.12-9-386 to match the version returned by the uname -a command. Installing the right version of the headers to match your kernel version is esssential. You may also need to install the gcc compiler.Load the module and Start lircdTest it with the irw utility. irw will output the commands received by the IR receiver that match your lircd.conf file. So start irw, point your remote and start pressing buttons.
# irw
000000037ff07bfe 00 One mceusb
000000037ff07bfd 00 Two mceusb
000000037ff07bfd 01 Two mceusb
000000037ff07bf2 00 Home mceusb
000000037ff07bf2 01 Home mceusb
If everything works, then autoload lirc_mceusb2 when your computer loads (how to depends on your distro) and start lircd as well (also depends on your distro).One note, I'm running a late-model Gentoo and I have to load lircd with this option:
# lircd -d /dev/lirc/0
Otherwise it fails, as it defaults to /dev/lircd. You will also need to install an lircrc file (note no dot at the front of the filename in the ~/.mythtv directory so that when the frontend starts up it can see the mythtv configuration settings for your remote control buttons.

2012年4月10日星期二

Variable Coding and Modulation (VCM) and Adaptive Coding and Modulation (ACM)

Background
Variable Coding and Modulation (VCM) and Adaptive Coding and Modulation (ACM) are techniques that are strongly associated with the DVB-S2 standard. VCM can be used to provide different levels of error protection to different components within the service. It does this by allowing different combinations of modulation and FEC rate to be applied to different parts of the data stream. ACM extends VCM by providing a feedback path from the receiver to the transmitter to allow the level of error protection to be varied dynamically in accordance with varying propagation conditions. Claims of performance improvements exceeding 100% have been made for ACM in terms of satellite capacity gain.
What is less well known is that the DVB-S2 VCM and ACM concepts can be applied to traditional Single Channel Per Carrier (SCPC) types of services and can offer similar benefits. This whitepaper gives an overview of how these concepts can be used outside of DVB-S2 satellite services.
DVB-S2 itself is offered by Paradise in SCPC modems and can be used in both SCPC and Multiple Channels Per Carrier (MCPC) modes. However, it is convenient to use a term that can be used to refer specifically to non DVB-S2 SCPC satellite services and the terms ‘SCPC’ and ‘traditional SCPC’ are used in this whitepaper for that purpose (even although traditional SCPC systems have themselves evolved to have an MCPC capability).
For the avoidance of doubt, the traditional SCPC services (i.e. all services offered by Paradise SCPC modems) that are being referred to include, but are not limited to the following: IBS and IDR framed satellite services, Closed Network services, Engineering Service Channel (ESC),Automatic Uplink Power Control (AUPC), Drop and Insert, TPC, Viterbi, Reed-Solomon, TCM, LDPC
(Including the low-latency variety), all traditional modulations (including 8QAM and 16QAM), multiplexing of data from multiple terrestrial interfaces onto a single carrier, MIL-STD-188-165A/B, etc. – all using a variety of terres- trial interface types including IP, EIA530, LVDS, G.703 and HSSI.

SCPC VCM
VCM can be used to extend traditional SCPC services in a similar manner to how it is used in DVB-S2. A quasi-error free quality target is set for each remote terminal as normal. The choice of modulation and FEC rate, which determines the strength of the error correction, will be determined by a number of factors including the position of the remote terminal within the satellite footprint.
The DVB-S2 concept of a frame can be applied to SCPC links along with all of the other DVB-S2 concepts including, but not limited to, mode adaptation, stream adaptation, baseband frames, mapping, pilots, dummy frames, scrambling, bit interleaving, constellation bit mapping, slots, generic continuous and generic packetized streams, stream synchronization, FEC frames and Physical Layer framing. When applied to traditional SCPC services, these DVB-S2 concepts perform similar functions and provide similar benefits to those documented for DVB-S2.
At its simplest, the user data (whether packetized or continuous) is put into baseband frames (possibly with padding), FEC information is added and then a Physical Layer (PL) header is prefixed prior to transmission to create the satellite frame for transmission.
The size of the baseband frames is dependent on the particular FEC scheme being used. For block based FECs such as LDPC and TPC, the baseband frame size is related to the block size of the FEC.Mode adaptation and stream adaptation deal with the issues of single and multiple stream inputs and merging and slicing of these streams into a sequence of satellite frames. A particular frame, PL header apart (see overleaf), is always transmitted in a homogeneous manner using a single modulation and FEC rate.
As with DVB-S2, particular information can be conveyed in the baseband header to help with decoding at the receiver, including:
Data format (packetized/continuous)
Single/multiple stream indicator
CCM/VCM/ACM indicator
Stream synchronisation information
Roll-off factor.
Also as with DVB-S2, particular information can be conveyed in the PL header to help with receiver synchronization and demodulation of the frame, including: Frame identification information Details of the FEC type, modulation and FEC rate used to encode the remainder of the frame Indication of the FEC frame length. All of the baseband and PL header fields can easily be extended to accommodate non-DVB-S2 pertinent data that is required for use of these techniques with traditional SCPC services (such as the use of alternative FECs to those specified in DVB-S2).
A key point is that the PL header is always transmitted using a particular robust modulation (BPSK is used in the DVB-S2 standard) and strong FEC rate. This helps the receiver lock onto the signal and it provides the information required to demodulate the remainder of the frame. When not receiving a signal, the receiver is automatically configured to detect any PL header, requiring just a centre frequency and symbol rate to have been set.
Note that the DVB-S2 concept of pilots (unmodulated symbols) can also be applied to make traditional SCPC services more robust.

SCPC ACM
ACM can be used to extend traditional SCPC services in a similar manner to how it is used in DVB-S2. The benefits include greater satellite throughput, reduced link Margins and higher service availability.SCPC ACM is applicable to both point-to-point and point- to-multipoint systems. In terms of a return channel, both a direct return channel over satellite and an indirect return channel via a terrestrial network can be used. Even over satellite, multiple separate SCPC return channels arePossible using receive-only modems at the hub, where the return information can be passed on to the transmit modem to allow it to optimize the strength of error correction for each stream as applicable to the channel conditions.
The concept of the DVB-S2 ACM command can equally be applied to traditional SCPC systems and for the same purpose. Signaling of reception quality via the return channel can be supported in SCPC systems, in particular continuous feedback of the carrier to noise plus interference ratio at the receiver along with other potential reception quality parameters (e.g. Eb/No, Modulation Error Rate (MER), Error Vector Magnitude (EVM) and suchlike).
SCPC ACM is particularly well suited for use in IP networks because mechanisms readily exist in terms of IP protocols such as Quality of Service provisioning, traffic shaping and TCP to feedback changes in data rate to the terrestrial network, allowing dynamic changes in satellite bandwidth due to varying reception conditions to be quickly reflected in the data stream to optimize use of the link.
In summary, the flexibility, robustness and efficiency of DVB-S2 VCM and ACM multistreaming features can now be used to extend traditional SCPC services, bringing the same benefits to all applications including cellular backhaul, ISP trucking and backbones, broadcast, teleports, government, military and SNG.
TBS6925
TBS6925 PCI express DVB S2 TV Tuner Card is a professional satellite PCTV tuner card. It is the first unique TV tuner card of supporting CCM, VCM, ACM mode and multiple Transport Stream receiving. With TBS6925, there are many unknown frequencies. It is the best TV tuner card for satellite hunter or enthusiasts.