Method of allocating carrier frequencies for simultaneous transmission of a plurality of modulated signals especially on an optical link

A method of allocating a plurality of carrier frequencies for simultaneous transmission of a plurality of modulated signals over a plurality of frequency channels in a transmission system, wherein said frequencies are chosen to satisfy the equation:

• f=(2p+1)n.+-.k
• where:
• p is an integer number specific to each carrier frequency;
• n represents a fixed frequency bandwidth, and either n is greater than a frequency bandwidth of the frequency channels occupied by said modulated signals if said frequency channels are all of the same width, or is greater than the frequency bandwidth of a widest one of said frequency channels if said frequency channels are not all of the same width;
• and
• k represents a given frequency bandwidth less than n and is greater than or equal to a null bandwidth;
• and
• wherein said modulated signals are television signals transmitted by vestigial sideband amplitude modulation, and wherein said frequency allocation conforms to the B, G, H and I standards and the allocated frequencies comprise frequencies in the UHF band from 471.25 MHz to 839.25 MHz in 16 MHz steps and frequencies in the VHF band of 55.25 MHz, 71.25 MHz and from 119.25 MHz to 455.25 MHz in 16 MHz steps.

A method of allocating a plurality of carrier frequencies for simultaneous transmission of a plurality of modulated signals over a plurality of frequency channels in a transmission system, wherein said frequencies are chosen to satisfy the equation:

• f=(2p+1)n.+-.k
• where:
• p is an integer number specific to each carrier frequency;
• n represents a fixed frequency bandwidth, and either n is greater than a frequency bandwidth of the frequency channels occupied by said modulated signals if said frequency channels are all of the same width, or is greater than the frequency bandwidth of a widest one of said frequency channels if said frequency channels are not all of the same width;
• and
• k represents a given frequency bandwidth less than n and is greater than or equal to a null bandwidth;
• wherein a frequency band including said carrier frequencies is divided into a lower band and an upper band;
• wherein said carrier frequencies in one of said lower and upper bands are chosen with k.noteq.0 and said carrier frequencies in the other of said upper and lower bands are chosen with k=0 so that any disturbances due to second order composite distortion are reduced without consideration of the ratio of the bandwidth n to the width of said channels, and of the capacity of the transmission system;
• and
• wherein said modulated signals are television signals transmitted by vestigial sideband amplitude modulation, said frequency allocation conforms to the L standard, and the frequencies allocated comprise frequencies in the UHF band from 471.25 MHz to 839.25 MHz in 16 MHz steps and frequencies in the VHF band of 56 MHz, 72 MHz and from 120 MHz to 456 MHz in 16 MHz steps.

A method of allocating a plurality of carrier frequencies for simultaneous transmission of a plurality of modulated signals over a plurality of frequency channels in a transmission system, wherein said frequencies are chosen to satisfy the equation:

• f=(2p+1)n.+-.k
• where:
• p is an integer number specific to each carrier frequency;
• n represents a fixed frequency bandwidth, and either n is greater than a frequency bandwidth of the frequency channels occupied by said modulated signals if said frequency channels are all of the same width, or is greater than the frequency bandwidth of a widest one of said frequency channels if said frequency channels are not all of the same width;
• and
• k represents a given frequency bandwidth less than n and is greater than or equal to a null bandwidth;
• and
• wherein said modulated signals are television signals transmitted by vestigial sideband amplitude modulation, said frequency allocation must conform to the M standard and the allocated frequencies comprise frequencies of 55.25 MHz, 67.25 MHz, 79.25 MHz and from 115.25 MHz to 643.25 MHz in 12 MHz steps.

A method of allocating carrier frequencies to frequency channels for simultaneous transmission of modulated signals in a transmission system, each of said frequency channels having a respective width, said method comprising the steps of:

• determining whether said frequency channels have an identical respective width;
• setting, when said frequency channels have said identical respective width, a value n of a fixed frequency bandwidth as being greater than said identical respective width;
• setting, when said frequency channels do not have said identical respective width, said value n of said fixed frequency bandwidth as being greater than said respective width of a widest one of said frequency channels;
• assigning to each of said carrier frequencies a respective integer number p;
• selecting a given frequency bandwidth k wherein 0.ltoreq.k<n;
• and allocating each frequency of said carrier frequencies so that f=(2p+1)n.+-.k.