DIPOL Weekly Review - TV and SAT TV, CCTV, WLAN

TD-SCDMA as the Chinese way to bypass 3G. Chinese market is in the lead in the world in terms of mobile phones being sold. It is 5 million pieces a month.
To become independent of world's 3G standards and not to pay for patents and licenses, the CATT (Chinese Academy of Telecommunications Technology) decided to develop its own standard.
Cooperating with Siemens company, Chinese engineers chose TD-SCDMA (Time Division-Synchronous Code Division Multiple Access) as the transmission technique for their national equivalent of 3G.
This month the standard was officially accepted, and the first commercial mobile is already deployed on the market. Currently the system is under test in (among others) the six future Olympic cities.
The TD-SCDMA technique uses bidirectional transmission with time sharing, i.e. there is common carrier frequency both for downlink and uplink connections, i.e. one physical channel. So, in a way, it is the opposite approach to the issue than that preferred e.g. in Europe - UMTS WCDMA uses two channels.
The essence of the method consists in assignment of orthogonal codes to different signals that can be transmitted on the same frequency. Additionally, the base stations synchronize time slots, which improves orthogonality of the signals.
Such transmission characteristics allows to use this technique in mobile TV.

Since January 2008, the first commercial TD-SCDMA network should be operational. However, the final decision on the basic 3G standard for the time of Olympic Games has not been made yet.

The principles of designing terrestrial TV installation. The diagram below shows example installation in a building. The table contains signal levels for three chosen outlets of the installation (denoted as "1", "2", "3") at 862 MHz, on the assumption that:

• input signal level measured at amplifier's input is 75 dBuV,
• gain of ZG amplifier is set to 45 dB, which results in 120 dB at the output.

Due to use of channel amplifiers there is no need to reduce output levels in the case of multiple channels (as an example - with broadband amplifier and 8 channels, a 7 dB reduction would be needed.This issue is discussed in the article Basics of designing MATV systems (English version in preparation - will be available next week).It is very important to obey the specifications of the employed amplifiers and not to exceed their maximum output levels. In the case of ZG amplifiers, the maximum output level is 123.5 dBuV. That's why with 75 dBuV at the input it is not allowed to set maximum gain (for ZG series: 53 dB), which would cause overdriving of the amplifier (128 dBuV) and high level of distortions.
In the example it is assumed that the lengths of the cables from taps to the outlets (BM-100 R90737) are 30 meters. Line sections are connected to the output of the set of channel amplifiers via the R-6 R60106 splitter and TRISET-11 cable. The same cable forms the beginning of each line going from output of the R6 splitter to the first tap (R602620). Attenuation of the TRISET-113 E1015_100 and TRISET-11 E1025_100 has been determined according to their specifications.
After the installation has been made, the installer should measure signal levels in the outlets, with the use of signal level meter - to verify the calculated values.The norms for TV distribution systems determine the acceptable range of signal level as 62 to 80 dBuV.

Number of outlet ->	1	2	3
Length of TRISET-11 [m]	90	30	60
Length of TRISET-113 [m]	36	33	30
Attenuation of the TRISET-11 [dB]	11.88	3.96	7.92
Attenuation of the TRISET-113 [dB]	6.51	5.97	5.43
Attenuation of R-6 splitter [dB]	10	10	10
Attenuation of O-X-1 tap [dB]	2	2	20
Attenuation of O-X-2 tap [dB]	3	16	0
Attenuation of O-X-3 tap[dB]	16	0	0
Attenuation of outlet [dB]	4	4	4
Reserve (e.g. loss in connectors) [dB]	3	3	3
Total attenuation of the network [dB]	56	45	50
Output level (120 dB) [dB]	64	75	70

Adjustment of data stream to the needs. NVR K3032 software package from ACTi allows recording, live monitoring, and support of client computers at the speed up to 25 fps. Similarly to other professional solutions, the system based on the software enables the administrator to adjust digital bandwidth pursuant to the needs and capacity of transmission channel and recording system. Flexible configuration of transmission parameters of video streams is possible due to client-server architecture.

Example solution:
The cameras provide video streams at speed of 25 fps to the server. Due to limited disc space, the NVR server records only 8 fps, but the operator can watch live images at full speed (25 fps) - thanks to the available bandwidth. The next computers working in another subnetwork are constrained by its low bandwidth so that they guarantee only 1 fps. But using Internet Explorer the computers provide access to the images and the previously recorded material.
Such client-server architecture allows deployment of wide-area systems, with highly flexible adjustment to limited network and recording capacity.

Example application of NVR system from ACTi

IP CCTV in fright forwarding company. Digital CCTV monitoring based on IP solutions becomes increasingly mainstream in video surveillance of buildings, parking lots, distribution centers etc. Not long ago the costs of professional IP CCTV monitoring systems were so high that they were mainly deployed in big cities. Recently the situation has changed significantly so that they may be used literally everywhere. IP CCTV systems ensure effective monitoring of geographically dispersed locations and building of installations with great number of cameras. They can be easily extended, reconfigured, and developed by software solutions. This cuts operational costs.
These were the decisive factors influencing choice of IP CCTV system in Spedkol company in Kedzierzyn-Kozle. The main problem in monitoring large industrial areas is cabling. Ripping up the roads, breaking through railway embankments etc. would make such undertaking too expensive, or even - due to current operational environment - practically impossible. So the priority was limitation of wired solutions and use of wireless transmission.
The monitoring system uses 8 IP cameras P400 K1131 from Pixord in Marathon housings. As managing and recording software there has been used professional software package Pixord P6032 that, among other functions, allows for:

• live monitoring and continuous or triggered by events recording of images from 32 cameras,
• PTZ control,
• advanced playback functions, including export of archives to any digital video format used in OS,
• export of images to any external monitoring center (remote monitoring)

The system equipped with 500 GB HDD enables the company to perform continuous and triggered recording in Full D1 resolution at 25 fps for approximately one week.
Pixord cameras

The camera Pixord P400 K1131 working in an office

Analog PTZ cameras in IP networks. Connection of such cameras to IP networks and full control of the PTZ functions is enabled by application of the video server PiXORD P1401 K2131 (one channel), or P4504 K2132 (four channels). They are equipped with analog (composite video) inputs and loop-through outputs, and connectors for RS485 interface enabling control of rotating cameras.
The both video servers support PELCO-P, PELCO-D, Li-Lin, and DynaColor protocols, which allows to control practically all types of analog PTZ cameras. The PTZ functions and viewing of the images is performed via Internet browser. In the case of K2131, the control is also possible through use of NVR software packages, e.g. P6032 (free addition to this model), as well as NUUO K3108, Milestone and many others.

DVR with DVD recorder becomes both a necessity and standard feature. Due to the risk of damaging HDD, hot swapping of hard disc from working DVR is not recommended. Aside from that, many manufacturers block possibility of reading the discs e.g. in a PC to protect authenticity of the recorded material. Additionally, it is a little bit difficult to pull out each time the HDD from its casing in order to make the backup.
The problems can be solved by choosing the DVRs equipped with DVD recorders. CP-CAM company offers the models CPD-505DVD M85077 and CPD-507DVD M8537. Besides recording of video, the DVRs can also record several audio channels. The newest firmware enables the user to make backup of event-triggered recordings onto DVD discs that can be later played on any PC. Of course, the video is synchronized with audio files. The DVD discs make always available archives, while the DVR working in overwrite mode can continuously record new data.
DVRs with DVD recorder

How to situate access point and configure wireless card. Proper choice of the location of access point is essential for the range of wireless network. In buildings, the signal is usually still useful after going through 3 walls or 2 floors. It means that the access point should be situated in a place where one uses the network most frequently, e.g. in the drawing room, study, bedroom etc. Generally, if the network is to cover whole house, it should be placed in the geometric center of the building. But having in mind the garden - it should be rather close to the window. So it is difficult to give a universal recipe for all cases.
Configuration of a wireless card is rather a straightforward task. According to its user's manual, one should install the needed drivers. The next step is setting appropriate IP address, gateway address of the rourter, mode of work, SSID of access point, and cipher keys. In the case of configured DHCP server, it is enough to set automatic assignment of IP and DNS parameters. Choosing a wireless adapter it is important to determine whether it supports the same data encryption method that is used by the access point.

Optimum location of the AP TL-WR542G N2950 in the house

Video Surveillance Conference and Exhibition ALARM. The event will take place in Kielce, Poland, from November 7-8, 2007.
The main purpose of the ALARM fair is to present offers related to security and emergency warning systems, video surveillance systems, personal protection means, equipment for special prevention squads and other modern professional solutions. In the pavilions of Kielce Trade Fairs visitors can become acquainted with services offered by security firms, investigation agencies, and insurance companies.
The fair is accompanied by the conference "Town Security - Video Surveillance of Urban Areas", the element of the program developed and implemented by Polish National Police in the largest cities.

See our virtual stand on the ALARM exhibition.