Handheld products to achieve DVB-H digital TV (with photos) - digital TV, mobile TV, digital TV set-top boxes - Broadcasting industry

Present, many buses, taxis, both to install a digital50%, 10 times the bandwidth, so if you can save
TV, this television technology used is DVB-T90%. In addition to lowering power consumption,
(Digital Video Broadcasting - Terrestrial). DVB-Tthe time slicing technology is also beneficial to
power comparison, it is not suitable fordifferent networks to achieve a smooth data
battery-powered mobile devices to use. To thisexchange. In the data transmission idle time, the
end, the DVB-T based on the introduction of newadjacent cellular mobile terminal can monitor,
technologies, form suitable for mobile terminals toscanning other frequency signals, test signal
receive terrestrial digital TV transmission standardstrength, this way when the user enters a new
DVB-H (digital video broadcasting - handheld).network, the mobile terminal to monitor the
Compared with DVB-T, DVB-H terminals withresults based on the idle time in the signal to
lower power consumption, mobile reception, andswitch to a different transport stream on
anti-jamming performance is superior.different networks to achieve a smooth data
DVB-H standard is based on DVB and DVB-Texchange.
standard on two criteria. A DVB-H systemDVB-H standard in the data link layer for the IP
receiver front-end is a DVB-H wrapper anddatagram added Reed? Solomon (RS) error
DVB-H modulator, DVB-H package is responsiblecorrection coding, as MPE forward error
for the IP data encapsulation into MPEG-2correction coding, verification of information in the
Systems Transport Stream (TS), DVB-Hspecified FEC ( FEC) section of the transmission,
modulator for the channel coding and modulation;that is multi-protocol Encapsulation - Forward Error
system terminal by the DVB-H DVB-HCorrection (MPE-FEC). MPE-FEC goal is to improve
demodulator and terminal form, DVB-Hthe mobile channel in S / N, pulse Doppler and
demodulator for channel demodulation, decoding,resistance to interference.
DVB-H terminal is responsible for operationsProved even in very poor reception environment,
related to processing, display.the proper use of MPE-FEC can still be accurate
Key technologies In DVB-H, the data link layerreconstruction of the IP data. MPE-FEC data
using the time slicing technology is the one brightoverhead allocation is very flexible, in other
spot, it is used to reduce average powertransmission parameters unchanged, if the
consumption of handheld devices to facilitate achecksum overhead to 25%, the MPE-FEC
smooth and seamless business exchange.enables handheld devices to and use of antenna
Multi-protocol encapsulation (MPE) FEC technologydiversity reception when the same S / N. DVB-H
to improve signal to noise ratio of mobile use (S /IP-based data broadcast, DVB-H physical layer
N) threshold and Doppler performance, but alsobased on the DVB-T supplement. In the DVB-T
can enhance the anti-pulse interference.system, 2K mode 8K mode better than the
Time Segmentation, by definition, Time Divisionmobile reception performance, but the 2K mode
Multiplexing technology. It solved the problemsymbol period and guard interval is very short, so
handheld mobile digital TV receiver in the high2K mode only for small single frequency
power consumption. As a result of burst modenetworks. DVB-H 4K mode increases with a
transmission of data, each burst transmission timelonger period and symbol guard interval, to the
slice of a business, delivery time in the business ofconstruction of medium-sized single-frequency
the business single-chip holds all the datanetwork, better network optimization, spectrum
bandwidth, and that the next time slice generatedefficiency. This optimization is not as efficient 8K
by the same business time. For the receiver, themode, but the 4K mode 8K mode symbol period
only time specified in the packet can receive data.than the short, more frequent channel estimation,
In this way, hand-held terminal can be selected toprovides a better mobile performance than the
receive the specified time business, free time to8K. Therefore, 4K mode and performs between
do energy conservation in business processing,2K and 8K modes, for coverage, spectral
thereby reducing the overall average powerefficiency and mobile reception performance of
consumption. Of course, this period is thethe trade-off to provide an additional option. 2K
front-end transmitter has been working in theand 4K mode in-depth symbol interleaver, can
same business will be sent between the two timefurther improve the environment and the impact
slots of other business data, DVB-H signal is theof noise in the mobile environment, the system
time slice by the number of such composition.reliability. Through the coordination of mobile
From the receiver's point of view, the operationalreception performance and the scale of a single
data received is not a constant rate as thefrequency network to further improve network
traditional continuous mode, the data arrivaldesign flexibility.
interval discrete way, to achieve burst transfer. IfReceiver design
the decoding terminal requests a lower data rate,Now many companies dedicated to portable
but must be a constant rate, the receiver canterminals DVB-H receiver module design. Here, I
first of all the received burst data to the buffer,described the reception module is Freescale's
and then generate the data flow rate unchanged.MC44CD02 direct conversion tuner and DiBcom's
Burst bandwidth is usually fixed at about 10 timesDiB7000-H channel decoder. Use of this tuner,
the bandwidth. Twice the bandwidth at a fixedusers can in a variety of harsh conditions are
bandwidth of sudden case of power could saveDVB-H services.