Error detector for encoded digital signals
AssigneeGeneral Electric Company
InventorNicola J. Fedele
Life of this patent
Estimating the term…
Abstract
A line marker signal is added to a DPCM encoded video signal to mark the beginning of each video scan line. The receiver searches for this marker signal and counts pixels between received markers, each scan line having a known number of pixels. The pixel count is checked against the known number of pixels in an error free system. If the pixel count differs from the known count, an error is indicated. The line marker signal is used to reset the decoder so the receiver is resynchronized at each scan line.
Claims13
An error detector for detecting the occurrence of errors in an encoded digital data information signal in a communication system, said signal comprising a plurality of codewords which may have different lengths, each codeword manifesting the value of at least one data item, said system tending to occassionally lose one or more data items, said detector comprising:
- means for periodically providing said data information signal a reference marker signal such that said data information signal has a given number of data items between adjacent successive reference marker signals;
- count means responsive to said information signal and said marker signals applied as an input thereto for generating a count signal representing the actual count of the number of received data items between each said adjacent successive reference marker signals;
- and
- means responsive to said count signal applied thereto for producing an error condition indication when the count of said count signal and said given number differ.
An error detector for detecting the occurrence of errors in an encoded digital data video information signal in a communication system, said signal manifesting a plurality of scan lines each having a plurality o pixels, each pixel encoded with a codeword of a given length, said system for transmitting said codewords to a receiver, said detector comprising:
- means for encoding said signal with a plurality of unique codeword reference marker signals for transmission to said receiver, each marker signal representing the beginning of a scan line, each scan line having the same given number of pixels;
- means for comparing the transmitted received encoded information signal with a reference signal manifesting said unique codeword marker signal to generate a line marker signal upon the occurrence of each said unique codeword marker signal in said received information signal;
- means responsive to said generated line marker signal for generating a count signal representing the number of pixels counted between successive ones of said marker signals;
- and
- means for indicating an error condition when the count of said count signal differs from said given number.
An error detector for determining loss of transmission of one or more encoded pixels in a digital video signal in a communication system, said signal comprising n pixels per scan line, said detector comprising:
- means for inserting a marker codeword in said signal to mark the beginning of each scan line;
- means for transmitting said signal including said marker codeword to a receiver;
- receiver means for detecting each said received marker codeword and for generating a marker signal in response to said detecting;
- means for counting the number of received pixels subsequent to each received marker and for generating a count signal manifesting the pixel count;
- means for comparing said marker signal with said count signal to generate a first signal when the count is n and a second signal when the count is less than n;
- and
- means responsive to said marker, first and second signals for generating an error indicating condition when only one of said marker and first signals are present.
Dependencies are inferred from the claim text.