Television standards conversion

Claim 1

A converter for generating at an output terminal from an input television signal an output television signal having a different field frequency, said converter comprising a delay device connected to delay said input signal by an integral number of input field periods or by an integral number of input field periods plus or minus an integral number of half input line-periods to provide, simultaneously with a line of a field of said input signal, at least one delayed signal at the output of said delay device which is a line from a previous input field; coupling means connected to said delay device and to receive said input signal to simultaneously provide said input signal, said delay signal or signals and/or linear combinations thereof; switching means connected to said coupling means to select for each output line a line from amongst the set comprising said input line and said delayed signal or signals and/or linear combinations thereof, the selection being made by allotting to each line of the set a range of positions in the picture for a range of times of occurrence and switching as the output line at any instant and at any position in the picture that line of the set within whose ranges the said instant and said position fall; and means connected to said switching means for applying the selected line to said output terminal.

Claim 5

A method of generating from an input television signal an output television signal having a different field frequency, the method comprising the steps of: delaying said input signal by an integral number of input field periods or by an integral number of input field periods plus or minus an integral number of half input line-periods to provide, simultaneously with a line of a fieLd of said input signal, at least one delayed signal which is a line from a previous input field; Simultaneously providing said input signal, said delayed signal, or signals and/or linear combinations thereof; and selecting for each output line a line from the set comprising said input line and said delayed signal or signals and/or linear combinations thereof, the selection being made by allotting to each line of the set a predetermined range of positions in the picture for a range of times of concurrence and switching as the output line at any instant and at any position in the picture that line of the set within whose ranges the said instant and said position fall.

Claim 6

A method of generating from an input television signal an output television signal having a different field frequency, the method comprising the steps of: delaying said input signal by an integral number of input field periods or by an integral number of input field periods plus or minus an integral number of half input line-periods to provide, simultaneously with a line of a fieLd of said input signal, at least one delayed signal which is a line from a previous input field; Simultaneously providing said input signal, said delayed signal, or signals and/or linear combinations thereof; and selecting for each output line a line from the set comprising said input line and said delayed signal or signals and/or linear combinations thereof, the selection being made by allotting to each line of the set a predetermined range of positions in the picture for a range of times of concurrence and switching as the output line at any instant and at any position in the picture that line of the set within whose ranges the said instant and said position fall.