Disc shaped recording medium having a zero track address and multibit opposite polarity track addresses and an address discrimination circuit for reading such recording medium

An address discriminating circuit for a recording medium in the form of a disc in which locations on said disc other than a predetermined location set as a zero-address are represented by (+) side addresses and (-) side addresses with respect to said zero address, and in which the information concerning these addresses are at least recorded as address data constituted by N bits, one of said (+) side address data and said (-) side address data being recorded in the form of said N bit data of which upper n bits, where N>n and n is at least 2, are all set to one of the binary states, with the remaining bits of said N bits representing the addresses, the other of said (+) side address data and said (-) side address data are recorded as data by said N bits exclusive of those data in which the upper nbits are in said one of said binary states, said address discriminating circuit comprising binary state discriminating means for discriminating the binary states of said upper n bits of said N bit address data read from said recording medium, and

• discriminating means for deciding the address data to be one of said (+) side address data and said (-) side address data if the binary state of all of said upper n bits as found by said binary state discriminating means is said one of the binary states, and discriminating the addresses based on remaining data of the N bits, said discriminating means deciding the address data to be the other of said (+) side address data and said (-) side address data if the binary state of the upper n bits as found by said binary state discriminating means is such binary state excluding data the states in which the n bits are all in said one of the binary states, and discriminating the addresses based on said N-bit data exclusive of such N-bit data in which the upper n bits of said N bits are all in the above-mentioned one of the binary states.

An address discriminating circuit for a recording medium in the form of a disc in which locations on said disc other than a predetermined location set as a zero-address are represented by (+) side addresses and (-) side addresses with respect to said zero address, and in which the information concerning these addresses are at least recorded as address data constituted by N bits, one of said (+) side address data and said (-) side address data being recorded in the form of said N bit data of which upper n bits, where N>n and n is at least 2, are all set to one of the binary states, with the remaining bits of said N bits representing the addresses, the other of said (+) side address data and said (-) side address data are recorded as data by said N bits exclusive of those data in which the upper n bits are in said one of said binary states, said address discriminating circuit comprising:

• an AND gate having a plurality of inputs, the inputs coupled for sensing from a first register the binary state of said upper n bits, and AND gate further having an output coupled to a second register to store the binary state of said output as a most significant bit;
• and
• the plurality of exclusive OR gates, each exclusive OR gate having at least two inputs, a first input of each exclusive OR gate connected in common and coupled to the output of the AND gate, as second input of each exclusive OR gate coupled to one input of the AND gate, each exclusive OR gate having an output coupled to store the binary state of such output as successive next most significant bits within the second register.