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DMB-T broadcast coverage in the mountainous areas of application


B-T system. DMB-T and DVB-T in Huangdao Yangtze River Road, Mt Road area has a blind spot, but DMB-T range of the small blind, the terrain factor is the main reason. DMB-Tall test a total of five break point along the way, including Yinchuan West Road and Jinsong field 23.1dB three-way intersection from the northwest along the road downhill to Jingkou its base field 23dBV; Kaiping intersection (Qingdao third depots) farm strong 23.2dBV more. Three reasons for the terrain, the signal by the Fushan, Northridge low-lying mountains block or field strength is weak. DVB-T a total of 56 breakpoints along the way, a total of 5 times longer pause,abercrombie marseille, excluding terrain factors, the main DVB-T system itself is the reason, anti-impulse noise, phase noise sensitivity is poor. DMB-T breakpoint occurred as 23 ~ 22dBV strong presence of the following, DVB-T breakpoint occurred as 27-28dBV strong presence of the following. Covering the area near the edge of the region, DVB-T due to noise ratio, field strength is relatively low and can not (go to 64) 64 5 industrial progress of the industry dynamics and application of 1) 2) ADTBT practical application of mobile reception program: private taxi to receive the fixed section: large-scale outdoor home TV media collection box electronic bulletin boards, high-speed mobile reception: Move to receive the maximum speed magnetic levitation train up 430km/h2004 nj has completed 960 years of agribusiness ADTBT taxi converted in 2005, plans to complete 15o00 taxi converted. ■ ■ l Editor: Cai Guoliang Received :2005 --03--31 (Continued from page 60) normally receive, while DMB health can be achieved under the same conditions normal to receive greater coverage area. DMBT farthest point 49km, DVBT farthest point 37km. In December 2004, in order to solve the urban areas Licun weak field problem areas in Qingdao, a single-frequency network trial. Master to keep power unchanged, up at the transmitter is located in Qingdao, Shandong Unicorn Hotel, floating roof, power output 200W. Test again, in the single-frequency presence, in the Qingdao urban area does not cover the basic dead spots in the region had occasional Licun the error problem completely solved. 3) the topography of Yunnan, Kunming, topographical features typical of the basin, concave part of the city located west of the basin, the urban radius of about 10km, the tower is located in the mountains west of downtown by the quake, the urban areas and diverse terrain. These have an impact on TV reception, especially for mobile reception greater impact. Yunnan TV Station in order to achieve simultaneous transmission of multiple programs, the use of 16QAM mode transmission in the 8MHz band of 10 sets of traditional analog television. As the current TV stations around the country to retain a large number of analog TV transmitters,ralph lauren pas cher, television broadcasting in the digital television broadcasting across age if people can take advantage of these transmitters will save the country a fortune. In Yunnan, Taiwan used to test transmitters for the broadcasting equipment company Anshan tube transmitter, using its final stage tube amplifier,abercrombie paris, transmitter pre-amplifier with FET. DMB-T RF signal from the front pole before the 1W amplifier input,christian louboutin france, the drive, drive pre-amplifier, the most! Man! Plastic baskets Man / final drive of the upper stage tube amplifier. Since the transmitter is designed for analog television transmission, so the whole non-linear performance is poor, not in 8MHZ band flatness to 10dB. In view of this, after the adjustment of the actuator in the + / 4.2MHz at the shoulder to 36dB. In order to receive both fixed and mobile reception, more programs to be sent to every household, the 10 sets of digital programming multiplexed (total bit rate of about 15Mbps) into the transmitter and open fired. In moving down the road and people receiving good results. To compare the performance of DMB and DVB systems, the use of Harris' DVBT transmitters, using the same amplifier, output power with DMBT under the same test coverage results. Test vehicle along the same lines comparison test, DVBT system error is very serious, in the mountains in the course of several F error occurred, the effect is significantly inferior to DMBT system. Through tests showed that the use of existing analog transmitter for simple technology upgrades after the broadcast digital television programs is entirely feasible. 4 Conclusion allow every family to watch TV is the wish of every radio and television workers, but in the mountainous region, the standard analog television determine the characteristics of this goal difficult to achieve. DMBT system as a new type of terrestrial digital TV broadcasting technology, its high sensitivity, anti-interference ability, support and other advantages of a single frequency network, making the mountainous region in the radio and television to millions of households possible. ■ ■ an Editor: Cai Guoliang Received :2005 -03-31
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