1. Field of the Invention
The present invention relates to digital television signals and, more particularly, to the receipt and measurement of off-air digital television signals.
2. Description of the Related Art
High Definition television (HDTV) sets and other digital digital set-top boxes must be able to receive digital signals, for example, terrestrial television signals. Terrestrial digital television signals will be received by the television set typically in addition to digital television signals from other sources. These other sources, such as cable and satellite (i.e., DBS), generally provide television signals at a standard signal strength that is sufficient to allow the television receiver to process and use the incoming digital television signal.
With both analog and digital off-air television signals, it is necessary to connect an antenna to the television set. If several digital channels are available, the user may be required to manually adjust the antenna in order to receive the best possible reception from all available channels. It is known to provide a channel search routine that will obtain a discrete sample or “snapshot” of all the currently available channels on the various antenna inputs. The channel search routine then stores the channels detected during the search in memory (e.g. EEPROM), deleting any channels previously stored that are not now currently available. At power-up of the unit, the channels in EEPROM become the channel list. If the user were to adjust or relocate the antenna, the signal strength of some digital signals (channels) may be too low to tune (or receive). Therefore at power-up or if the user runs a channel search, various channels may be deleted. Further, weak channels are removed to allow for the case where a user moves to another broadcast location (off-air, cable, or DBS).
It may be the case that several digital television signals are available to the user but only if the antenna is manually adjusted to achieve the best possible reception for the various channels. To efficiently achieve the best antenna placement, the user would need to know the signal strengths of the various digital television channels. Also, with the use of a rotor and control electronics, the best position for the antenna relative to each digital television channel could be obtained, stored, and utilized, if the signal strength of each digital television channel were known.