Video signal converter

Claim 2

A video signal converter comprising: a ROM table having frequencies, each of the frequencies being associated with already-existing formats of video signals; an operation panel; selecting means for selecting a first frequency Fi from the ROM table based on a format of a first video signal input through the operation panel, the first frequency Fi having the maximum value which satisfies a formula: Fi≦(To×Fo)/Ti, where the Ti is a horizontal scanning period of the first video signal, the To is a horizontal scanning period of a second video signal, and the Fo is a second frequency; first clock generating means for generating a first clock of the first frequency Fi; second clock generating means for generating a second clock of the second frequency Fo; analog-to-digital converting means for converting the first analog video signal to first digital video data according to a sampling clock of the first frequency Fi; writing means for writing the first digital video data into a memory in synchronization with the first clock; reading means for reading the first digital video data from the memory in synchronization with the second clock to generate second digital video data; and digital-to-analog converting means for converting the second digital video data to a second analog video signal in synchronization with the second clock.

Claim 3

A video signal converter comprising: a ROM table having frequencies, each of the frequencies being associated with already-existing formats of video signals; an operation panel; selecting means for selecting a first frequency Fi from the ROM table based on a format of a first video signal input through the operation panel, the first frequency Fi having the maximum value which satisfies a formula: Fi≦(To×Fo)/Ti, where the Ti is a horizontal scanning period of the first video signal, the To is a horizontal scanning period of a second video signal, and the Fo is a second frequency; first clock generating means for generating a first clock of the first frequency Fi; second clock generating means for generating a second clock of the second frequency Fo; analog-to-digital converting means for converting the first analog video signal to first digital video data according to a sampling clock of the first frequency Fi; writing means for writing the first digital video data into a memory in synchronization with the first clock; reading means for reading the first digital video data from the memory in synchronization with the second clock to generate second digital video data; an NTSC encoder for encoding the second digital video data to generate video data of the NTSC format; and digital-to-analog converting means for converting the NTSC video data to an NTSC analog video signal in synchronization with the second clock.

Claim 4

A video signal converter comprising: a ROM table having frequencies, each of the frequencies being associated with already-existing formats of video signals; an operation panel; selecting means for selecting a first frequency Fi from the ROM table based on a format of a first video signal input through the operation panel, the first frequency Fi having the maximum value which satisfies a formula: Fi≦(To×Fo)/Ti, where the Ti is a horizontal scanning period of the first video signal, the To is a horizontal scanning period of a second video signal, and the Fo is a second frequency; first clock generating means for generating a first clock of the first frequency Fi; second clock generating means for generating a second clock of the second frequency Fo; analog-to-digital converting means for converting the first analog video signal to first digital video data according to a sampling clock of the first frequency Fi; writing means for writing the first digital video data into a memory in synchronization with the first clock; reading means for reading the first digital video data from the memory in synchronization with the second clock to generate second digital video data; an NTSC encoder for encoding the second digital video data to generate video data of the NTSC format; and digital-to-analog converting means for converting the NTSC video data to an NTSC analog video signal in synchronization with the second clock.

Claim 5

A video signal converter according to claim 2, wherein said first analog video signal is comprised of RGB signals.

Claim 6

A video signal converter according to claim 2, wherein said first analog video signal is a signal of HDTV format.

Claim 7

A video signal converter according to claim 2, wherein said second frequency Fo satisfies an equation: Fo=4×Fsc, where Fsc is a color subcarrier frequency of the NTSC format.

Claim 8

A video signal converter according to claim 3, wherein said second frequency Fo satisfies an equation: Fo=4×Fsc, where Fsc is a color subcarrier frequency of the NTSC format.

Claim 9

A video signal converter according to claim 4, wherein said second frequency Fo satisfies an equation: Fo=4×Fsc, where Fsc is a color subcarrier frequency of the NTSC format.

Claim 10

A video signal converter comprising: analog-to-digital converting means for converting a first analog video signal to first digital video data; a ROM table having width-to-height ratios of pixels, each of the ratios being associated with already-existing formats of video signals; an operation panel; line conversion ratio setting means for setting a line conversion ratio R which satisfies an equation: R=m/k, where the 1/m is a width-to-height ratio read from the ROM table based on a format of the first video signal input through the operation panel, the 1/k is a width-to-height ratio of a second video data; converting means for converting the first digital video data having a first number of scanning lines to the second digital video data having a second number of scanning lines, the second number being R-times the first number; and digital-to-analog converting means for converting the second digital video data to a second analog video signal.

Claim 11

A video signal converter comprising: analog-to-digital converting means for converting a first analog video signal to first digital video data; a ROM table having width-to-height ratios of pixels, each of the ratios being associated with already-existing formats of video signals; an operation panel; line conversion ratio setting means for setting a line conversion ratio R which satisfies an equation: R=m/k, where the 1/m is a width-to-height ratio read from the ROM table based on a format of the first video signal input through the operation panel, the 1/k is a width-to-height ratio of a second video data; converting means for converting the first digital video data having a first number of scanning lines to the second digital video data having a second number of scanning lines, the second number being R-times the first number; and digital-to-analog converting means for converting the second digital video data to a second analog video signal.

Claim 12

A video signal converter comprising: analog-to-digital converting means for converting a first analog video signal to first digital video data; a ROM table having width-to-height ratios of pixels, each of the ratios being associated with already-existing formats of video signals; an operation panel; line conversion ratio setting means for setting a line conversion ratio R which satisfies an equation: R=m/k, where the 1/m is a width-to-height ratio read from the ROM table based on a format of the first video signal input through the operation panel, the 1/k is a width-to-height ratio of a second video data; converting means for converting the first digital video data having a first number of scanning lines to the second digital video data having a second number of scanning lines, the second number being R-times the first number; an NTSC encoder for encoding the second digital video data to generate video data of the NTSC format; and digital-to-analog converting means for converting the video data of the NTSC format to an analog video signal of the NTSC format.

Claim 13

A video signal converter comprising: analog-to-digital converting means for converting a first analog video signal to first digital video data; a ROM table having width-to-height ratios of pixels, each of the ratios being associated with already-existing formats of video signals; an operation panel; line conversion ratio setting means for setting a line conversion ratio R which satisfies an equation: R=m/k, where the 1/m is a width-to-height ratio read from the ROM table based on a format of the first video signal input through the operation panel, the 1/k is a width-to-height ratio of a second video data; converting means for converting the first digital video data having a first number of scanning lines to the second digital video data having a second number of scanning lines, the second number being R-times the first number; an NTSC encoder for encoding the second digital video data to generate video data of the NTSC format; and digital-to-analog converting means for converting the video data of the NTSC format to an analog video signal of the NTSC format.

Claim 14

A video signal converter according to claim 9, wherein said first analog video signal is comprised of RGB signals, each of the RGB signals having a width-to-height ratio 1/1 of each pixel, respectively.

Claim 15

A video signal converter according to claim 9, wherein said first analog video signal is a signal of HDTV format.

Claim 16

A video signal converter comprising: a ROM table having frequencies and width-to-height ratios of pixels, each of the frequencies and each of the ratios being associated with already-existing formats of video signals; an operation panel; selecting means for selecting a first frequency Fi from the ROM table based on a format of a first video signal input through the operation panel, the first frequency Fi having the maximum value which satisfies a formula: Fi≦(To×Fo)/Ti, where the Ti is a horizontal scanning period of the first video signal, the To is a horizontal scanning period of a second video signal, and the Fo is a second frequency; first clock generating means for generating a first clock of the first frequency Fi; second clock generating means for generating a second clock of the second frequency Fo; analog-to-digital converting means for converting the first analog video signal to first digital video data according to a sampling clock of the first frequency Fi; line conversion ratio setting means for setting a line conversion ratio R which satisfies an equation: R=m/k, where the 1/m is width-to-height ratio read from the ROM table based on a format of the first video signal input through the operation panel, the 1/k is a width-to-height ratio of a second video data; converting means for converting the first digital video data having a first number of scanning lines to the second digital video data having a second number of scanning lines, the second number being R-times the first number; a frame memory writing means for writing the first digital video data into the frame memory in synchronization with the first clock; reading means for reading the first digital video data from the frame memory in synchronization with the second clock to generate the second digital video data; and digital-to-analog conversion means for converting the second digital video data to the second analog video signal in synchronization with the second clock.

Claim 17

A video signal converter comprising: a ROM table having frequencies and width-to-height ratios of pixels, each of the frequencies and each of the ratios being associated with already-existing formats of video signals; an operation panel; selecting means for selecting a first frequency Fi from the ROM table based on a format of a first video signal input through the operation panel, the first frequency Fi having the maximum value which satisfies a formula: Fi≦(To×Fo)/Ti, where the Ti is a horizontal scanning period of the first video signal, the To is a horizontal scanning period of a second video signal, and the Fo is a second frequency; first clock generating means for generating a first clock of the first frequency Fi; second clock generating means for generating a second clock of the second frequency Fo; analog-to-digital converting means for converting the first analog video signal to first digital video data according to a sampling clock of the first frequency Fi; line conversion ratio setting means for setting a line conversion ratio R which satisfies an equation: R=m/k, where the 1/m is width-to-height ratio read from the ROM table based on a format of the first video signal input through the operation panel, the 1/k is a width-to-height ratio of a second video data; converting means for converting the first digital video data having a first number of scanning lines to the second digital video data having a second number of scanning lines, the second number being R-times the first number; a frame memory writing means for writing the first digital video data into the frame memory in synchronization with the first clock; reading means for reading the first digital video data from the frame memory in synchronization with the second clock to generate the second digital video data; and digital-to-analog conversion means for converting the second digital video data to the second analog video signal in synchronization with the second clock.

Claim 18

A video signal converter comprising: a ROM table having frequencies and width-to-height ratios of pixels, each of the frequencies and each of the ratios being associated with already-existing formats of video signals; an operation panel; selecting means for selecting a first frequency Fi from the ROM table based on a format of a first video signal input through the operation panel, the first frequency Fi having the maximum value which satisfies a formula: Fi≦(To×Fo)/Ti, where the Ti is a horizontal scanning period of the first video signal, the To is a horizontal scanning period of a second Video signal, and the Fo is a second frequency; first clock generating means for generating a first clock of the first frequency Fi; second clock generating means for generating a second clock of the second frequency Fo; analog-to-digital converting means for converting the first analog video signal to first digital video data according to a sampling clock of the first frequency Fi; line conversion ratio setting means for setting a line conversion ratio R which satisfies an equation: R=m/k, where the 1/m is width-to-height ratio read from the ROM table based on a format of the first video signal input through the operation panel, the 1/k is a width-to-height ratio of a second video data; converting means for converting the first digital video data having a first number of scanning lines to the second digital video data having a second number of scanning lines, the second number being R-times the first number; a frame memory writing means for writing the first digital video data into the frame memory in synchronization with the first clock; reading means for reading the first digital video data from the frame memory in synchronization with the second clock to generate the second digital video data; and an NTSC encoder for encoding the second digital video data to generate video data of the NTSC format; and digital-to-analog converting means for converting the video data of the NTSC format to an analog video signal of the NTSC format.

Claim 19

A video signal converter comprising: a ROM table having frequencies and width-to-height ratios of pixels, each of the frequencies and each of the ratios being associated with already-existing formats of video signals; an operation panel; selecting means for selecting a first frequency Fi from the ROM table based on a format of a first video signal input through the operation panel, the first frequency Fi having the maximum value which satisfies a formula: Fi≦(To×Fo)/Ti, where the Ti is a horizontal scanning period of the first video signal, the To is a horizontal scanning period of a second Video signal, and the Fo is a second frequency; first clock generating means for generating a first clock of the first frequency Fi; second clock generating means for generating a second clock of the second frequency Fo; analog-to-digital converting means for converting the first analog video signal to first digital video data according to a sampling clock of the first frequency Fi; line conversion ratio setting means for setting a line conversion ratio R which satisfies an equation: R=m/k, where the 1/m is width-to-height ratio read from the ROM table based on a format of the first video signal input through the operation panel, the 1/k is a width-to-height ratio of a second video data; converting means for converting the first digital video data having a first number of scanning lines to the second digital video data having a second number of scanning lines, the second number being R-times the first number; a frame memory writing means for writing the first digital video data into the frame memory in synchronization with the first clock; reading means for reading the first digital video data from the frame memory in synchronization with the second clock to generate the second digital video data; and an NTSC encoder for encoding the second digital video data to generate video data of the NTSC format; and digital-to-analog converting means for converting the video data of the NTSC format to an analog video signal of the NTSC format.

Claim 20

A video signal converter according to claim 13, wherein said first analog video signal is comprised of RGB signals, each of the RGB signals having a width-to-height ratio 1/1 of each pixel, respectively.

Claim 21

A video signal converter according to claim 13, wherein said first analog video signal is a signal of HDTV format.

Claim 22

A video signal converter according to claim 13, wherein said second frequency Fo satisfies an equation: Fo=4×Fsc, where Fsc is a color subcarrier frequency of the NTSC format.

Claim 23

A video signal converter according to claim 14, wherein said second frequency Fo satisfies an equation: Fo=4×Fsc, where Fsc is a color subcarrier frequency of the NTSC format.

Claim 24

A video signal converter according to claim 15, wherein said second frequency Fo satisfies an equation: Fo=4×Fsc, where Fsc is a color subcarrier frequency of the NTSC format.