Inserting and separating frequency folding information

Claim 2

A frequency folding information inserting circuit as claimed in claim 1, wherein said position of insertion of said frequency folding information (DF) is set between one vertical synchronous signal (VS) and the next subsequent vertical synchronous signal (VS).

Claim 3

A frequency folding information inserting circuit as claimed in claim 2, wherein said position of insertion of said frequency folding information (DF) is set between an arbitrary horizontal synchronous signal (HS) and the next subsequent horizontal synchronous signal (HS) in an interval between one vertical synchronous signal (VS) and the next subsequent vertical synchronous signal (VS).

Claim 4

A frequency folding information inserting circuit as claimed in claim 3, wherein said frequency folding information (DF) is positioned during any arbitrary horizontal scanning period (HS).

Claim 5

A frequency folding information separating circuit (490) in a video reproducing apparatus including a luminance reproducer (420) for reproducing a folded luminance signal from a video signal recorded by folding a high frequency video signal into a low frequency video signal so as to record the folded video signal of a full bandwidth on a recording medium of a limited bandwidth, and a frequency unfolder (450) for generating a luminance signal of a full bandwidth by unfolding the folded high frequency luminance signal into the original frequency band, said circuit (490) comprising: a position detector (120) for detecting an insertion position of frequency folding information from synchronous signals included in said reproduced luminance signal; and a frequency folding information separator (130) for separating the frequency folding information inserted in said reproduced luminance signal by responding to the detected result of said position detector (120) and supplying the separated frequency folding information to said frequency unfolder (450).

Claim 6

A frequency folding information separating circuit as claimed in claim 5, wherein said position detector (120) comprises a synchronous signal separator for separating the synchronous signals from the reproduced luminance signal.

Claim 7

A frequency folding information generating method for representing a frequency folding state of a folded video signal in a video recording apparatus for folding a high frequency video signal into a low frequency video signal and for recording the folded video signal of a full bandwidth on a recording medium of a limited bandwidth, said method comprising the steps of: separating a horizontal synchronous signal and a vertical synchronous signal from the folded video signal including synchronous signals; generating a standard clock pulse train having a frequency which is a predetermined number of times higher than that of the horizontal synchronous signal; counting up a scanning period of the horizontal synchronous signal according to said standard clock pulse train; comparing the counted value with a value corresponding to a half-period of the horizontal synchronous signal when a blanking duration of the vertical synchronous signal starts during said counting-up step; generating an even/odd number field detection signal of a predetermined logic state according to the compared result at said comparing step; generating frequency folding information according to the logic state of said generated even/odd number field detection signal; and setting a position of a scanning line for inserting said frequency folding information.

Claim 8

A frequency folding information generating method as claimed in claim 7, wherein a value of said frequency folding information is increased by one for every inversion of the logic state of the even/odd number field detection signal in said generating step of said frequency folding information.

Claim 9

A frequency folding information generating method as claimed in claim 8, wherein said frequency folding information takes a value of "0" after reaching a specified value in said generating step of said frequency folding information.

Claim 10

A frequency folding information generating method as claimed in claim 9, wherein said frequency folding information takes a value of "0" after reaching a value of "3".

Claim 11

A frequency folding information generating method as claimed in claim 7, wherein said frequency folding information is a pulse in which an inserting position of the pulse is slightly altered for each field.

Claim 12

A frequency folding information generating method as claimed in claim 7, wherein said frequency folding information is an impulse in which an inserting position of the impulse is slightly altered for each field.

Claim 13

A frequency folding information generating method as claimed in claim 7, wherein said frequency folding information is a code word with a fixed inserting position.

Claim 14

A frequency folding information generating method as claimed in claim 7, wherein said frequency folding information is generated to be inserted in only any one field of four fields of the video signal in said generating step of the frequency folding information.

Claim 15

A frequency folding information generating method as claimed in claim 7, wherein said frequency folding information is generated to be inserted in only any two fields of four fields of the video signal.

Claim 16

A frequency folding information generating method as claimed in claim 7, wherein said frequency folding information is generated to be inserted in only any three fields of four fields of the video signal.