ession schemes allow multiple streams of programming, along with the ability to control information per transponder frequency, made DBS feasible, and research and development continues in this area. Squeezing down the signal still further would be an advantage, but providers also want to eliminate the occasional blocky digital compression artifacts that some viewers find distracting. With High Definition Television (HDTV) on the horizon, three or four times more bandwidth (or three or four times better compression) will be required to provide the same number of channels. Currently, each DBS provider uses its own format for transmitting the signal. An emerging world standard, DVB, uses MPEG-2 and also attempts to standardize other elements of the system. Still, even DVB-compliant systems from different providers are not interchangeable. In addition to HDTV, demand for local channels drives the push for more bandwidth. Besides improving compression, other areas of technological development include higher-power transponders, which allow more information to pass through existing bandwidth because less error-correcting coding is required. Signal polarization, controlling the orientation of the electromagnetic wave transmissions, is used to isolate adjacent transponder slots and allow more of them within a fixed-frequency spectrum. Statistical multiplexing maximizes the use of existing bandwidth by assigning it upon demand, depending on the information density of a particular program being carried by a channel at a given time.Another approach to the bandwidth problem might be to expand it using spot-beam broadcasts to individual markets, although satellites capable of such transmissions in the DBS frequency spectrum did not yet exist as of mid-1998. Capital Broadcasting of Raleigh, North Carolina plans to provide local programming packages from a satellite with 61 beams by about 2001.Technological development is also addressing the pro...
