To view a television program being transmitted to a user""s television, the user provides a channel number to the television. In conventional analog broadcast television, this channel number is a reference to a particular frequency band at which the analog signal carrying the television program is broadcast. This frequency band is also referred to as a xe2x80x9cphysical channel.xe2x80x9d The channel number identifies from which frequency band a tuner in the television is to receive. Thus, a channel number indicates a physical channel and the associated program.
In digital broadcast television, a frequency band can carry a signal which is an encoded digital transport stream. When decoded, the transport stream can include one or more streams having various forms of content, such as video or audio for a program, text based information, closed captioning, or any information which can be transmitted digitally. Each of these items can be associated with a different channel number. Accordingly, a single physical channel can include multiple items or xe2x80x9cvirtual channels.xe2x80x9d In this case, a channel number refers to a virtual channel, a particular item encoded within a transport stream, instead of referring to a physical channel.
In addition, content in a transport stream can be related to content broadcast as an analog signal or in a different transport stream. For example, a transport stream can include a high definition television (xe2x80x9cHDTVxe2x80x9d) version of a program that is also broadcast as an analog signal at a different unrelated frequency band.
The invention provides methods and apparatus implementing a technique for selecting a channel in a digital television. In one implementation, selecting a channel includes: receiving a major and minor channel number sequence, including a major channel number, a delimiter, and a minor channel number, where the delimiter separates the major channel number and the minor channel number; identifying a physical channel which corresponds to the major and minor channel number sequence by accessing a channel look up table, where the channel look up table includes correspondences between major and minor channel number sequences and physical channels; and identifying a virtual channel table which corresponds to the physical channel, where the virtual channel table indicates a virtual channel which corresponds to the major and minor channel number sequence. Selecting a channel can further include: tuning to the physical channel to receive a signal carried on the physical channel; and decoding the virtual channel from the tuned signal.
In another aspect, an input device for selecting a channel in a digital television includes: a keypad including a plurality of number keys for inputting respective numbers; and a delimiter key for inputting a delimiter, where a channel is indicated by a major and minor channel number sequence which includes a major channel number input through one or more number keys of the keypad, a delimiter input through the delimiter key, and a minor channel number input through one or more number keys of the keypad.
In another aspect, a digital television includes: a display; a tuner including a connection for an externally supplied broadcast signal, where the tuner provides a signal carried on a physical channel selected from the broadcast signal; a channel control circuit which derives major and minor channel number sequences from received control signals, where a major and minor channel number sequence indicates a specific channel carried in the broadcast signal; a channel processing circuit connected to the channel control circuit, the display, and the tuner, where the channel processing circuit causes the tuner to select a physical channel corresponding to the major and minor channel number sequence supplied by the channel control circuit and provide a digital signal carried thereon, decodes a channel indicated by the major and minor channel number sequence in the digital signal, and supplies the decoded channel to the display.
USPTO Backgrounds
USPTO Backgrounds