Patent ID: 7433438

Claim:
A vestigial side band (VSB) synchronization (sync) signal detection circuit, comprising: a data selector selecting one of a first data signal and a second data signal for output; a pseudo-random number 511 (PN 511 ) sequence detector receiving the selected first or second data signal, generating a plurality of correlation values for symbols of the received first or second data signal, outputting only those correlation values that exceed a first threshold as correlation values corresponding to a detected PN 511 sequence of a VSB signal, and outputting a first control signal related to sync signal generation; a comparison buffer unit receiving the correlation values exceeding the first threshold from the PN 511 sequence detector, storing a maximum correlation value among the received correlation values, generating a second control signal containing information regarding the position of a symbol in which the maximum correlation value is generated, comparing a next maximum correlation value to a second threshold, and generating a third control signal based on the result of comparison; a sync signal position determination unit receiving the second control signal, determining positions of a next field sync signal and one or more segment sync signals, and generating a fourth control signal containing information regarding the positions of the next field sync signal and one or more segment sync signals based on the received second control signal; a sync signal valid determination unit receiving the third and fourth control signals and generating at least one valid detection signal indicating that a generated field sync signal is valid based on a level of the third control signal and a level of the fourth control signal; a finite state machine (FSM) that generates an internal lock signal in response to a valid detection signal, wherein the internal lock signal is fed back to the sync signal valid determination unit; a pseudo-random number 63 (PN 63 ) correlator receiving the selected first or second data signal from the data selector, detecting correlation values corresponding to a PN 63 sequence of the received first or second data signal, and generating a fifth control signal for determining the sign of a field sync signal; and a sync signal generator outputting one or more distinct types of sync signals in response to the first control signal, fourth control signal, fifth control signal, and internal lock signal.