Line standard converter for converting a television signal having a number of n-lines per image into a television signal having a number of m-lines per image

Claim 1

A line standard converter for converting a first television signal having a number of lines per image into a second television signal having a selected number of lines per image while maintaining the number of images per second, said converter comprising a television signal input means for receiving said first signal, a switchable storage circuit coupled to said input means comprising a plurality of switchable line stores, means for writing said input signal into said stores in a selected period, means for reading a signal from said stores in a selected period, the write period having a value differing from the read pereiod, said reading and writing means comprising means for effecting the conversion ratio of the line standard converter between n and m substantially equal to 1/2 , said plurality of line stores being at least equal to (2 + 1/2 q) for q equals zero or a positive even number and being equal to (2 1/2 + 1/2 q) for q equals a positive odd number, in which q for m greater than 1/2 n is equal to m - 1/2 n - 1/2 and for n less than 1/2 m is equal to 1/2 n - m - 1/2 , wherein for a value of n which is one less than a multiple of 4, q is odd when m is greater than 1/2 n and q is even when m is less than 1/2 m and for a value of n which is one more than a multiple of four q is odd when m is less than 1/2 n and q is even when m is greater than 1/2 n, m being one of said number of lines per image and n being the remaining one of said number of lines per image.