Backward compatible multiple data stream transmission method and system for compressed domain signals

A device for generating a compressed domain composite signal including data bits from a first digital data stream signal and a second digital data stream signal, and being suitable for transmission to and for reception by a first receiver being adapted to receive said first digital data stream signal and a second receiver being adapted to receive said composite digital signal, said device comprising:

• a first forward error correction device including an input adapted to receive said first digital data stream signal and an output, wherein said first digital data stream signal includes a first plurality of digital data bits;
• a second forward error correction device including an input adapted to receive said second digital data stream signal and an output, wherein said second digital data stream signal includes a second plurality of digital data bits;
• and,
• means for selectively replacing select ones of said first plurality of data bits with data bits from said second plurality to generate said composite signal;
• wherein, said means for selectively replacing said select data bits is coupled to said first and second forward error correction devices and said select ones of said first plurality of data bits are selected such that at least a given percentage of said first plurality of data bits are included in said composite signal.

A receiver suitable for receiving compressed domain digital signals, said receiver comprising:

• a first error correction device for correcting errors in a first signal;
• a second error correction device for correcting errors in a second signal;
• and,
• means for receiving a composite signal including data bits from said first signal and data bits from said second signal and applying said bits from said first and second signals to said first error correction device and said data bits from said second signal to said second error correction device;
• wherein said first signal is adapted to be received by a first type of receiver.

A method for receiving a composite, compressed domain, digital signal comprising:

• receiving a composite signal including data bits corresponding to a first signal and data bits corresponding to a second data signal, wherein said composite signal is adapted to be received by a receiver adapted to receive said first signal;
• and,
• applying said data bits corresponding to said first data signal and data bits corresponding to said second data signal to a first circuit and said data bits corresponding to said second signal to a second circuit;
• wherein said first signal is an ATSC DTV signal;
• and
• wherein said composite signal includes a plurality of first type data bits, a plurality of second type data bits and a plurality of third type data bits;
• and said data bits corresponding to said second signal are select ones of said first type of data bits.

A method for operating a compressed domain digital signal transmission and reception system comprising:

• providing a first signal including a first plurality of data bits and second signal including a second plurality of data bits;
• determining a threshold value for said first signal, said threshold value being indicative of a percentage of said first plurality of data bits;
• identifying select ones of said first plurality of bits dependent upon said threshold value;
• substituting data bits from said second plurality for said select bits of said first plurality to generate a composite signal;
• and,
• applying said data bits corresponding to said first signal and said data bits corresponding to said second signal to a first decoding circuit and said data bits corresponding to said second signal to a second decoding circuit;
• wherein said composite digital data stream signal is adapted to be effectively received and decoded by receivers to receive said first digital data stream signal and receivers adapted to receive said composite digital data stream signal.