Receiver for jam-resistant TV system
AssigneeRCA Corporation
InventorStanley S. Brokl
Life of this patent
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Abstract
A jam-resistant receiver for a TV signal in which each vertical sync pulse is replaced by several increasingly-delayed symbols from a pseudo-random number generator. A correlator produces a correlation pulse on receipt of a predetermined one of the symbols. The pulse is used to generate reconstituted vertical sync pulses having the correct phase. If the correlation pulse falls below a threshold value due to interference, the receiver automatically shifts to the use of a different symbol for synchronization.
Claims10
A jam-resistant receiver for a TV signal in which each vertical synchronizing pulse is replaced by several sequential symbols from a pseudo-random number (PN) generator, the several symbols occurring with increasing phase delays relative to the vertical synchronizing pulse, comprising
- a correlator receptive to said sequential symbols and containing a predetermined one of said symbols at a reference, and producing a correlation pulse when the correlator receives a symbol which is the same as the reference,
- synchronization reconstituting means responsive to the correlation pulse and the known phase delay of the predetermined symbol in the sequence of symbols to produce a reconstituted vertical synchronizing pulse for synchronizing the received video, and
- detector means operative when said correlation pulse is below a predetermined threshold to change the reference symbol in the correlator.
Dependencies are inferred from the claim text.