The Open Mobile Video Coalition (OMVC) has released a new set of tools designed to help Mobile DTV consumer electronics product manufacturers enhance reception by reducing the need for expensive field testing and to help TV station engineers design robust mobile systems.
The OMVC forecasts that Mobile DTV service will reach two-thirds of the viewing public over the next year, as many more stations add Mobile DTV capability to their transmission systems.
The signal qualities of Mobile DTV are different than HDTV transmissions, because antennae in Mobile DTV receivers are usually lower to the ground and always on the move. The OMVC has been developing several new services that will help the deployment of the system.
The OMVC website features a Mobile DTV Propagation study that reviews the reception characteristics of mobile video service options and explains the “RF Capture” program service for device manufacturers. The group is also releasing a Recommended Practices document for the deployment of electronic service guides and a presentation about the most likely broadcast scenarios for Mobile DTV services—including 11 case studies for multiple channels at varying qualities of transmission.
The OMVC’s new Predictive Model for reception of UHF (Channels 14 to 51) Mobile DTV signals is intended to predict signal coverage in automobiles with an antenna mounted on the vehicle, in a handheld unit operating outdoors and a handheld unit operating indoors. Broadcaster radio-frequency (RF) experts can use this new model to predict RF coverage of existing or future transmission facilities.
Future iterations of the Predictive Reception Model will consider the impact of elliptical or circular polarized transmission antennae, the effects of tall buildings near receivers and details on predictive reception for VHF reception.
Over the past several months, OMVC has coordinated the recording of live over-the-air Mobile DTV radio-frequency (RF) signals in the Washington, D.C. market. The recording of RF television signals is an efficient and cost-effective method of assisting broadcasters and receiver designers in better understanding their reception environment. The RF signal capture program was initiated in March to create a signal library that will both assist broadcasters in better understanding their reception environments and help mobile device product developers improve their products.
The RF Capture Catalog is a collection of profiles that allow broadcasters and product developers to play back these profiles in the laboratory for more thorough analysis and evaluation of the Mobile DTV RF environment. Different captures of RF television signals will help broadcasters determine the relative performance between the two services and their expected coverage.
