Detection of PN sequences accompanying VSB signal to control operating mode of QAM/VSB DTV signal receiver

A television signal radio receiver for selectively receiving vestigialsideband (VSB) digital television (DTV) signals and television signals of at least one other type, said television signal radio receiver comprising:

• circuitry for demodulating VSB DTV signals to generate a first baseband signal;
• respective circuitry for demodulating each said other type of television signal to generate a respective further baseband signal;
• first and second match filters of similar type connected to receive as their respective input signals in-phase and quadrature-phase components of said first baseband signal, said first match filter for supplying a first match filter response to PN sequence information in the data field synchronization segment of a VSB DTV baseband signal as can appear in the in-phase component of said first baseband signal, and said second match filter for supplying a second match filter response to said PN sequence information in the data field synchronization segment of a VSB DTV baseband signal as can appear in the quadrature-phase component of said first baseband signal;
• circuitry for determining the combined energy of said first match filter response and said second match filter response;
• a threshold detector for determining when the combined energy of said first match filter response and said second match filter response is sufficient in energy to provide a pulse indication of an occurrence in said first baseband signal of the PN sequence information in the data field synchronization segment of a received VSB DTV transmission;
• timed latch circuitry for latching the indication for a period of time longer than at least one DTV data field;
• and
• circuitry for operating the television signal radio receiver either in a VSB DTV reception mode or in a reception mode for another type of television signal, depending on an output signal of said timed latch circuitry.

A television signal radio receiver for selectively receiving vestigial-sideband (VSB) digital television (DTV) signals and television signals of at least one other type, said television signal radio receiver comprising:

• circuitry for demodulating VSB DTV signals to generate a first baseband signal;
• respective circuitry for demodulating each said other type of television signal to generate a respective further baseband signal;
• first and second match filters of similar type connected to receive as their respective input signals in-phase and quadrature-phase components of said first baseband signal, said first match filter for supplying a first match filter response to triple PN63 sequence information in the odd data field synchronization segment of a VSB DTV baseband signal as can appear in the in-phase component of said first baseband signal, and said second match filter for supplying a second match filter response to said triple PN63 sequence information in the odd data field synchronization segment of a VSB DTV baseband signal as can appear in the quadrature-phase component of said first baseband signal;
• circuitry for determining the combined energy of said first match filter response and said second match filter response;
• a first threshold detector for determining when the combined energy of said first match filter response and said second match filter response is sufficient in energy to provide a pulse indication of an occurrence in said first baseband signal of the triple PN63 sequence information in the odd-data-field synchronization segment of a VSB DTV transmission;
• third and fourth match filters of similar type connected to receive as their respective input signals said in-phase and quadrature-phase components of said first baseband signal, said third match filter for supplying a third match filter response to triple PN63 sequence information in the even data field synchronization segment of a VSB DTV baseband signal as can appear in the in-phase component of said first baseband signal, and said fourth match filter for supplying a fourth match filter response to said triple PN63 sequence information in the even data field synchronization segment of a VSB DTV baseband signal as can appear in the quadrature-phase component of said first baseband signal;
• circuitry for determining the combined energy of said third match filter response and said fourth match filter response;
• a second threshold detector for determining when the combined energy of said third match filter response and said fourth match filter response is sufficient in energy to provide a pulse indication of an occurrence in said first baseband signal of the triple PN63 sequence information in the even-data-field synchronization segment of a VSB DTV transmission;
• an OR gate for supplying an OR gate response to each said pulse indication of an occurrence in said first baseband signal of the triple PN63 sequence information in the odd-data-field synchronization segment of a VSB DTV transmission and to each said pulse indication of an occurrence in said first baseband signal of the triple PN63 sequence information in the even-datafield synchronization segment of a VSB DTV transmission;
• timed latch circuitry for latching the OR gate response for a period of time longer than at least one DTV data field;
• and
• circuitry for operating the television signal radio receiver either in a VSB DTV reception mode or in a reception mode for another type of television signal, depending on an output signal of said timed latch circuitry.