Data decoder
First Claim
1. A decoder for decoding data from a video signal of the type including a series of horizontal line segments, one of the lined segments including a data signal in a normally unused part thereof, said apparatus comprising means for digitizing said video signal to form a series of digitized line signals, means for receiving each of said digitized line signals, in sequence, said receiving means comprising shift register means having an input operably connected to receive said digitized line signals, means for clocking said shift register means, means for detecting the presence of a data signal within said receiving means, means for controlling said receiving means to store the data signal in response to the detection thereof, and means for transferring said stored data signal from said receiving means.
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Accused Products
Abstract
The decoder is capable of locating a data signal within any horizontal line of a video signal, thereby eliminating the necessity for keeping track of the line numbers. The pre-data portion is detected and the data portion is stored in the same register. DC level restoration of the video signal is performed periodically during digitizing. When the decoder is used to receive a data signal in the standard FCC waveform, the clock run in portion, normally used for synchronization in conventional decoders, is detected and the operating rate of the register is adjusted to the rate of the data portion for a number of clock signals equal to the number of data bits to capture the data portion. Once the data has been captured, further signals are prevented from entering the register for approximately one frame to permit the stored data to be retrieved.
112 Citations
37 Claims
- 1. A decoder for decoding data from a video signal of the type including a series of horizontal line segments, one of the lined segments including a data signal in a normally unused part thereof, said apparatus comprising means for digitizing said video signal to form a series of digitized line signals, means for receiving each of said digitized line signals, in sequence, said receiving means comprising shift register means having an input operably connected to receive said digitized line signals, means for clocking said shift register means, means for detecting the presence of a data signal within said receiving means, means for controlling said receiving means to store the data signal in response to the detection thereof, and means for transferring said stored data signal from said receiving means.
- 20. A decoder for decoding data from a video signal of the type consisting of a series of horizontal line segments, one of the line segments including a data signal in a section not normally used, the data signal comprising data synchronizing portion at a first data rate and a data portion at a second data rate, said apparatus comprising means for digitizing said video signal to form a series of digitized line signals, means for receiving each of said digitized line signals, in sequence, said receiving means normally operating at the first data rate, means for detecting the presence of the data synchronizing portion within said receiving means, means, effective upon detection of said data synchronizing portion, to control said receiving means to store said data portion, said controlling means comprising means for operating said receiving means at the second data rate, and means for terminating the operation of said receiving means after the data portion is received therein, and means for transferring said stored data from said receiving means.
- 33. Apparatus for slicing and stabilizing a video signal, said apparatus comprising slicing level source means, DC level source means, first comparator means having first and second inputs, said first input of said first comparator means being operably connected to receive said video signal, said second input of said first comparator means being operably connected to said slicing level source and means for operably connecting said DC level source to said first input of said first comparator means to periodically adjust the DC level of said video signal.
Specification