Code-error correcting device

Claim 1

A code-error correcting device for use in an apparatus for transmitting digital information as well as address information, said code-error correcting device comprising: an address generating circuit for generating an address information signal indicating address information or data block information relating to address information; a pseudo-random-function generating circuit for receiving the address information signal as indicating an initial value for computing pseudo-random functions and responsive to the address information signal for generating pseudo-random functions; and an adder circuit for computing the EXCLUSIVE OR of the digital information and an output of the pseudo-random function generating circuit and further supplying the value of the EXCLUSIVE OR to a digital modulator as an input thereof.

Claim 7

An apparatus for recording digital information on a recording medium and reproducing the recorded information therefrom, said apparatus having an encoder for generating signals indicating error-detecting-and-correcting code and a decoder for receiving digital demodulation information, to which address information is added, and for effecting error-correction of reproduced digital speech signal, said encoder including a first code-error correcting device and on the other hand said decoder including a second code-error correcting device, said first code-error correcting device comprising: an address generating circuit for generating an address information signal indicating address information or data block information relating to address information; a first pseudo-random-function generating circuit for receiving the address information signal as indicating a first initial value for computing pseudo-random functions and responsive to the address information signal for generating and outputting pseudo-random function; and a first adder circuit for computing the EXCLUSIVE OR of the digital information and an output of said first pseudo-random function generating circuit and further supplying the value of the EXCLUSIVE OR to a digital modulator as an input thereof, said second code-error correcting device comprising: a demodulation address generating circuit for generating a demodulation address information signal indicating demodulation address information or demodulation data block information relating to demodulation address information; a second pseudo-random-function generating circuit for receiving the demodulation address information signal as indicating a second initial value, which is different from the first initial value, for computing pseudo-random function and responsive to the demodulation information signal for generating and outputting pseudo-random function different from the pseudo-random function outputted by said first pseudo-random-function generating circuit; and a second adder circuit for calculating the EXCLUSIVE OR of the digital demodulation information and an output of the pseudo-random function generating circuit and further supplying the value of the EXCLUSIVE OR to a circuit for deriving the original digital information therefrom, thereby preventing erroneous data from outputting therefrom even if no error occurs in the receiving system thereof.

Claim 8

An apparatus for recording digital information on a recording medium and reproducing the recorded information therefrom, said apparatus having an encoder for generating signals indicating error-detecting-and-correcting code and a decoder for receiving digital demodulation information, to which address information is added, and for effecting error-correction of reproduced digital speech signal, said encoder including a first code-error correcting device and on the other hand said decoder including a second code-error correcting device, said first code-error correcting device comprising: an address generating circuit for generating an address information signal indicating address information or data block information relating to address information; a first pseudo-random-function generating circuit for receiving the address information signal as indicating a first initial value for computing pseudo-random functions and responsive to the address information signal for generating and outputting pseudo-random function; and a first adder circuit for computing the EXCLUSIVE OR of the digital information and an output of said first pseudo-random function generating circuit and further supplying the value of the EXCLUSIVE OR to a digital modulator as an input thereof, said second code-error correcting device comprising: a demodulation address generating circuit for generating a demodulation address information signal indicating demodulation address information or demodulation data block information relating to demodulation address information; a second pseudo-random-function generating circuit for receiving the demodulation address information signal as indicating a second initial value, which is different from the first initial value, for computing pseudo-random function and responsive to the demodulation information signal for generating and outputting pseudo-random function different from the pseudo-random function outputted by said first pseudo-random-function generating circuit; and a second adder circuit for calculating the EXCLUSIVE OR of the digital demodulation information and an output of the pseudo-random function generating circuit and further supplying the value of the EXCLUSIVE OR to a circuit for deriving the original digital information therefrom, thereby preventing erroneous data from outputting therefrom even if no error occurs in the receiving system thereof.