Start code for signalling bits
AssigneeU.S. Philips Corporation
InventorsJohannes Y. Tichelaar, Franciscus H. M. Bergen, Philippe A. M. Van Overmeire, Jilles Ultee
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Abstract
In an extended television signal having signalling bits for conveying control information to control an extended decoder, the signalling bits include a start code and data bits. The start code's main lobe of spectral energy resides in the lower spectral area of a baseband television signal below 2 MHz and preferably below 1.7 MHz. The start code is preferably (almost) DC-free, and the start code has good aperiodic correlation properties and a predetermined minimum bit Hamming distance to the data bits when shifted in the direction of the data bits following the start code.
Claims26
A method for encoding an extended television signal comprising the steps:
- generating signalling bits for conveying control information to control an extended decoder;
- inserting the signalling bits into an extended television signal;
- and
- providing said extended television signal with said signalling bits for transmission;
- wherein the signalling bits comprise a start code and data bits, the start code having a main lobe of spectral energy residing in a lower spectral area of a baseband television signal, said lower spectral area having a maximum frequency below 2 MHz, the start code having an amplitude dip at zero frequency, and the start code having minimum predetermined aperiodic correlation properties and a predetermined minimum bit Hamming distance to the data bits when shifted in the direction of the data bits following the start code.
An extended television signal decoder, comprising:
- means coupled to receive an extended television signal comprising image data, signalling bits for conveying control information to control processing operations with regard to said image data, and synchronizing information, for deriving said synchronizing information from said extended television signal;
- means coupled to receive said synchronizing information for selecting a signalling bits window;
- means coupled to receive said extended television signal for decoding said signalling bits during said signalling bits window;
- wherein the signalling bits comprise a start code and data bits, and wherein the start code's main lobe of spectral energy resides in the lower spectral area of a baseband television signal, said lower spectral area having a maximum frequency below 2 MHz, the start code having a local spectral minimum at DC, and the start code having predetermined minimum aperiodic correlation properties and a predetermined minimum bit Hamming distance to the data bits when shifted towards or over the data bits following the start code.
A method of decoding an extended television signal, comprising the steps of:
- receiving an extended television signal comprising image data, signalling bits for conveying control information to control processing operations with regard to said image data, and synchronizing information, for deriving said synchronizing information from said extended television signal;
- selecting a signalling bits window in dependence on said synchronizing information;
- decoding said signalling bits during said signalling bits window in response to said extended television signal;
- wherein the signalling bits comprise a start code and data bits, the start code's main lobe of spectral energy residing in the lower spectral area of a baseband television signal, said lower spectral area having a maximum frequency below 2 MHz, the start code having a local spectral minimum at DC, and the start code having predetermined minimum aperiodic correlation properties and a predetermined minimum bit Hamming distance to the data bits when shifted towards or over the data bits following the start code.
Dependencies are inferred from the claim text.