Method and apparatus for digital audio broadcasting and reception

A transmitter system for a system for broadcast transmission and reception of digitized program material, said transmitter system comprising:

• first signal processing means coupled to accept digitized program material from a source of digitized program material for encoding said digitized program material according to a BCH code having at least 200 data bits and no more than 20 check bits to produce a digital representation of a block encoded signal;
• second signal processing means for generating an equivalent of a plurality of equivalent tones which are spaced equally at a baseband between 0 Hz and a selected maximum frequency, each of said equivalent tones being at a frequency which is an integer multiple of a base frequency tone and each one of said equivalent tones being constrained to be phase coherent with said unmodulated pilot tone, said second signal processing means being coupled to accept said digital representation of said block-encoded signal for quadrature phase shift key (QPSK) modulating each one of said equivalent tones with said digital representation of said block-encoded signal thereby to distribute said digital representation of said block-encoded signal over substantially all of said equivalent tones in order to produce a multitone QPSK modulated signal at a selected intermediate frequency carrier signal;
• and
• means for translating said intermediate frequency carrier signal to an output carrier and broadcasting said output carrier through atmospheric free-space.

A receiver system for a system for broadcast transmission and reception of digitized program material in the form of a multitone QPSK modulated signal, wherein said digitized program material is encoded according to a BCH block code having at least 200 data bits and no more than 20 data bits in a block encoded signal, said receiver system comprising:

• means for acquiring a replica of said multitone QPSK modulated block encoded signal through atmospheric free-space, said atmospheric free-space being subject to multipath such that said replica is inclusive of transmission errors;
• first signal processing means coupled to receive said replica of said replica of said multitone QPSK modulated block encoded signal for coherently demodulating said replica of said multitone QPSK modulated signal into a replica of said block encoded signal;
• and
• second signal processing means for decoding said replica of said digital representation of said block encoded signal into output program material with correction of selected short-interval-dependent data errors, narrow-band frequency-dependent data errors and long-interval broadband frequency dependent data errors, such as induced by multipath effects, said output program material being a substantial duplicate of said digitized program material.

A method for transmitting, in a broadcast transmission and reception system, digitized program material, said method comprising the steps of:

• encoding, in first signal processing means coupled to accept digitized program material from a source of digitized program material, said digitized program material according to a BCH code having at least 200 data bits and no more than 20 check bits to produce a digital representation of a block encoded signal;
• generating an equivalent of a plurality of equivalent tones which are spaced equally at a baseband between 0 Hz and a selected maximum frequency, each of said equivalent tones being at a frequency which is an integer multiple of a base frequency tone and each one of said equivalent tones being constrained to be phase coherent with said unmodulated pilot tone, and quadrature phase shift key (QPSK) modulating each one of said equivalent tones with said digital representation of said block-encoded signal thereby to distribute said digital representation of said block-encoded signal over substantially all of said equivalent tones in order to produce a multitone QPSK modulated signal at a selected intermediate frequency carrier signal;
• translating said intermediate frequency carrier signal to an output carrier;
• and
• broadcasting said output carrier through atmospheric free-space.

A method for receiving an analog signal and digitized program material in the form of a multitone QPSK modulated signal, wherein said digitized program material is encoded according to a BCH block code having at least 200 data bits and no more than 20 check bits in a block encoded signal, said method comprising the steps of:

• acquiring a replica of said multitone QPSK modulated block encoded signal through atmospheric free-space, said atmospheric free-space being subject to multipath such that said replica is inclusive of transmission errors;
• coherently demodulating said replica of said multitone QPSK modulated signal into a replica of said block encoded signal;
• and
• decoding said replica of said block encoded signal into output program material with correction of selected short-interval-dependent data errors, narrow-band frequency-dependent data errors and long-interval broadband frequency dependent data errors, such as induced by multipath effects, said output program material being a substantial duplicate of said digitized program material.