There are two frequency charts that are linked from this page.  One chart covers the standard over-the-air broadcast channel numbers and their frequencies.   The second chart provides data for the standard cable channels (CATV / EIA).   The standard broadcast channels are the twelve VHF channels 2 through 6 and 7 through 13.  The UHF channels are numbered 14 to 83, but some of these channels have been reassigned to other types of non-television communications services.  All of these broadcast channels have three valid frequencies for each and every channel.   The frequency shown for each channel is the "center frequency" of the NTSC visual carrier for that channel.  In order to minimize interference between two television stations that could share the same channel number, a 10-kilohertz frequency offset is assigned to television stations that are nearby (200 miles is typical).  The three valid picture carrier frequencies for a US television station operating on channel 2 would be 55.240 MHz, 55.250 MHz and 55.260 MHz.  There are no other channel 2 video transmitter frequencies for use in the United States.  The same plus and minus 10 kilohertz spacings apply to all VHF and UHF television channels for broadcast transmission in the US.

The color and sound information contained in an NTSC television signal will have the following frequency offsets from the video carrier frequencies.  The color sub-carrier has a frequency of 3.579545 MHz.  This sub-carrier is phase modulated with the color information of the picture and occupies approximately 1 MHz of bandwidth.   The sound carrier is a frequency modulated signal with an average frequency of 4.5 MHz, plus or minus 1 kilohertz.  The occupied bandwidth of this signal is approximately 75 kilohertz or less.  When digital television signals become widespread, there will be a single carrier with all video and audio information as part of the digital bit stream.  The resulting quadrature modulated carrier will be centered in the 6 MHz channel.  The standard NTSC video carriers are normally 1.25 MHz above the lower band edge of the channel, while the sound carrier is 0.25 MHz below the upper band edge of the channel.  These two offsets are the result of the 4.5 MHz difference in the two carrier frequencies.

As for the cable channels, there are different rules.  Since the signals are to be kept inside the coaxial cable environment, many additional channel frequencies exist.   In the event of signal leakage into the air, the channels which could interfere with aviation radio navigation and communications have frequency offsets applied to them of 12.5 kilohertz or 25 kilohertz.  Any other cable channel which does not pose a risk to aviation frequencies will not have a frequency offset.