Method and apparatus for reducing distortion in multicarrier communication systems

Claim 3

The method as in claim 1 wherein the amplitudes of all of said carriers are maintained at substantially the same value before being combined for transmission.

Claim 10

In a multi-carrier communication system, the improvement comprising; a. means to estalish a harmonically related coherent frequency relationship between the carriers of said system; b. means to signal modulate each of said carriers and to combine said carriers to transmit a signal which is their vector sum, said signal having a periodic wave form with a frequency equal to the fundamental frequency of said harmonically related carrier; and c. means to adjust the phase of each of said carriers with respect to the zero phase reference of said fundamental frequency by a predetermined amount in the range of 0* to 360*, the combined effect of all of said phase adjustments being to substantially minimize the peak-to-peak amplitude excursion of said combined vector sum transmitted signal from its maximum possible value.

Claim 11

In a multi-carrier communication system, the improvement comprising; a. means to estalish a harmonically related coherent frequency relationship between the carriers of said system; b. means to signal modulate each of said carriers and to combine said carriers to transmit a signal which is their vector sum, said signal having a periodic wave form with a frequency equal to the fundamental frequency of said harmonically related carrier; and c. means to adjust the phase of each of said carriers with respect to the zero phase reference of said fundamental frequency by a predetermined amount in the range of 0* to 360*, the combined effect of all of said phase adjustments being to substantially minimize the peak-to-peak amplitude excursion of said combined vector sum transmitted signal from its maximum possible value.

Claim 12

In a multi-carrier CATV cable system, the improvement comprising: a. means to establish a harmonically related coherent frequency relationship between the carriers of said system; b. means to signal modulate each of said plurality of carriers to transmit a television program signal and means to combine said modulated carriers to transmit a signal which is their vector sum, said signal having a periodic wave form with a frequency equal to the fundamental frequency of said harmonically related carriers; c. means to adjust the phase of each of said carriers with respect to the zero phase reference of said fundamental frequency by predetermined amounts which together substantially minimize the peak-to-peak amplitude excursion of said combined vector sum transmitted signal from its maximum possible value; and d. wherein the value of said fundamental frequency and the frequency of the periodic waveform of said transmitted signal is equal to 6 MHz and wherein said carriers are respectively the the 9th, 10th, 11th, 13th, 14th, 25th and 29th through 35th harmonics of said fundamental frequency, and wherein the phase measured in radians of each of said carriers with respect to the zero phase reference of said fundamental is as follows: 9th 0; 10th 0; 11th -1.630; 13th -1.709; 14th -1.402; 25th -1.492; 29th 0; 30th 0; 31st -1.562; 32nd -1.408; 33rd +1.554; 34th -1.418; and 35th +1.884.

Claim 13

In a multi-carrier CATV cable system, the improvement comprising: a. means to establish a harmonically related coherent frequency relationship between the carriers of said system; b. means to signal modulate each of said plurality of carriers to transmit a television program signal and means to combine said modulated carriers to transmit a signal which is their vector sum, said signal having a periodic wave form with a frequency equal to the fundamental frequency of said harmonically related carriers; c. means to adjust the phase of each of said carriers with respect to the zero phase reference of said fundamental frequency by predetermined amounts which together substantially minimize the peak-to-peak amplitude excursion of said combined vector sum transmitted signal from its maximum possible value; and d. wherein the value of said fundamental frequency and the frequency of the periodic waveform of said transmitted signal is equal to 6 MHz and wherein said carriers are respectively the the 9th, 10th, 11th, 13th, 14th, 25th and 29th through 35th harmonics of said fundamental frequency, and wherein the phase measured in radians of each of said carriers with respect to the zero phase reference of said fundamental is as follows: 9th 0; 10th 0; 11th -1.630; 13th -1.709; 14th -1.402; 25th -1.492; 29th 0; 30th 0; 31st -1.562; 32nd -1.408; 33rd +1.554; 34th -1.418; and 35th +1.884.

Claim 14

In a multi-carrier CATV cable system, the improvement comprising: a. means to establish a harmonically related coherent frequency relationship between the carriers of said system, b. means to signal modulate each of said plurality of carriers to transmit a television program signal and means to combine said modulated carriers to transmit a signal which is their vector sum, said signal having a periodic wave form with a frequency equal to the fundamental frequency of said harmonically related carriers; c. means to adjust the phase of each of said carries with respect to the zero phase reference of said fundamental frequency by predetermined amounts which together substantially minimize the peak-to-peak amplitude excursion of said combined vector sum transmitted signal from its maximum possible value; and d. wherein the frequency of said fundamental and of said periodic waveform of said transmitted signal has a value equal to 6 MHz and wherein said carriers are the 9th, 10th, 11th, 13th, 14th, and 20th through 39th harmonics of said fundamental, and wherein the phases measured in radians of each of said carriers respectively with respect to the zero phase reference point of said fundamental is as follows: 9th 0; 10th 0; 11th 0; 13th 0; 14th 0; 20th -1.382; 21st -1.451; 22nd -1.520; 23rd -1.444; 24th -1.507; 25th 0; 26th -1.588; 27th -1.526; 28th -1.582; 29th 0; 30th +1.444; 31st 0: 32nd 0; 33rd +1.597; 34th 0; 35th 0; 36th +1.584; 37th +3.014; 38th +2.791; and 39th +1.224.

Claim 15

In a multi-carrier CATV cable system, the improvement comprising: a. means to establish a harmonically related coherent frequency relationship between the carriers of said system, b. means to signal modulate each of said plurality of carriers to transmit a television program signal and means to combine said modulated carriers to transmit a signal which is their vector sum, said signal having a periodic wave form with a frequency equal to the fundamental frequency of said harmonically related carriers; c. means to adjust the phase of each of said carries with respect to the zero phase reference of said fundamental frequency by predetermined amounts which together substantially minimize the peak-to-peak amplitude excursion of said combined vector sum transmitted signal from its maximum possible value; and d. wherein the frequency of said fundamental and of said periodic waveform of said transmitted signal has a value equal to 6 MHz and wherein said carriers are the 9th, 10th, 11th, 13th, 14th, and 20th through 39th harmonics of said fundamental, and wherein the phases measured in radians of each of said carriers respectively with respect to the zero phase reference point of said fundamental is as follows: 9th 0; 10th 0; 11th 0; 13th 0; 14th 0; 20th -1.382; 21st -1.451; 22nd -1.520; 23rd -1.444; 24th -1.507; 25th 0; 26th -1.588; 27th -1.526; 28th -1.582; 29th 0; 30th +1.444; 31st 0: 32nd 0; 33rd +1.597; 34th 0; 35th 0; 36th +1.584; 37th +3.014; 38th +2.791; and 39th +1.224.

Claim 16

In a multi-carrier CATV cable system, the improvement comprising: a. means to establish a harmonically related coherent frequency relationship between the carriers of said system: b. means to signal modulate each of said plurality of carriers to transmit a television program signal and means to combine said modulated carriers to transmit a signal which is their vector sum, said signal having a periodic wave form with a frequency equal to the fundamental frequency of said harmonically related carriers; c. means to adjust the phase of each of said carriers with respect to the zero phase reference of said fundamental frequency by predetermined amounts which together substantially minimize the peak-to-peak amplitude excursion of said combined vector sum transmitted signal from its maximum possible value; and d. wherein the value of said fundamental frequency and the frequency of the periodic waveform of said transmitted signal is equal to 6 MHz and wherein said carriers are the fundamental and the 2nd through the 20th harmonic thereof and wherein the phases measured in degrees and decimal parts of degrees for each of said carriers with respect to the zero phase reference of said fundamental is as follows: the 1st through 9th and the 18th harmonics are each zero phase; 10th -72.02; 11th -71.28; 12th +86.41; 13th +84.23; 14th +90.71; 15th -97.20; 16th -92.13; 17th +97.88; 19th +72.04; and 20th -86.45.

Claim 17

In a multi-carrier CATV cable system, the improvement comprising: a. means to establish a harmonically related coherent frequency relationship between the carriers of said system: b. means to signal modulate each of said plurality of carriers to transmit a television program signal and means to combine said modulated carriers to transmit a signal which is their vector sum, said signal having a periodic wave form with a frequency equal to the fundamental frequency of said harmonically related carriers; c. means to adjust the phase of each of said carriers with respect to the zero phase reference of said fundamental frequency by predetermined amounts which together substantially minimize the peak-to-peak amplitude excursion of said combined vector sum transmitted signal from its maximum possible value; and d. wherein the value of said fundamental frequency and the frequency of the periodic waveform of said transmitted signal is equal to 6 MHz and wherein said carriers are the fundamental and the 2nd through the 20th harmonic thereof and wherein the phases measured in degrees and decimal parts of degrees for each of said carriers with respect to the zero phase reference of said fundamental is as follows: the 1st through 9th and the 18th harmonics are each zero phase; 10th -72.02; 11th -71.28; 12th +86.41; 13th +84.23; 14th +90.71; 15th -97.20; 16th -92.13; 17th +97.88; 19th +72.04; and 20th -86.45.

Claim 18

Headend equipment for a system for cable distribution of a plurality of multiplexed television programs on a plurality of channels as a single cable signal, said cable signal being the vector sum of the respective individual carriers of each of said programs, said equipment comprising: a. a source of system frequency synchronizing signal maintained at a fixed fundamental frequency equal to said program bandwith; b. program signal source means to provide a separate program modulated video carrier for each of said channels; c. means to establish a harmonically related coherent frequency relationship between said carriers and said source of synchronizing signal such that the video carrier for each of said channels has a frequency which may be any integral multiple of the frequency of said first synchronizing signal fundamental frequency, said fundamental frequency synchronizing signal thus simultaneously controlling the frequency relationships of said video carriers for said plurality of channels and setting the minimum frequency separation between the video carriers of adjacent pairs of channels at an integral multiple of the frequency of said first synchronizing signal, each of said coherent harmonic video carriers being physically derived from said fundamental frequency synchronizing signal itself to maintain the harmonic frequency relationship even with drift in the fundamental so that the sum and difference beat frequency of any order which result from any beat combination of said video carriers and which fall within one of said channels will always zero beat with the video carriers thereof; d. means to combine said carriers for transmission as a single cable signal; and e. means to control the phase relationship of each of said harmonically related coherent carriers with respect to the zero phase reference of their fundamental to reduce the peak value of their vector sum in said cable signal from its maximum possible value which occurs if all of said carriers reach their peak simultaneously to thereby reduce distortion during transmission of said cable signal through said cable.

Claim 19

Headend equipment for a system for cable distribution of a plurality of multiplexed television programs on a plurality of channels as a single cable signal, said cable signal being the vector sum of the respective individual carriers of each of said programs, said equipment comprising: a. a source of system frequency synchronizing signal maintained at a fixed fundamental frequency equal to said program bandwith; b. program signal source means to provide a separate program modulated video carrier for each of said channels; c. means to establish a harmonically related coherent frequency relationship between said carriers and said source of synchronizing signal such that the video carrier for each of said channels has a frequency which may be any integral multiple of the frequency of said first synchronizing signal fundamental frequency, said fundamental frequency synchronizing signal thus simultaneously controlling the frequency relationships of said video carriers for said plurality of channels and setting the minimum frequency separation between the video carriers of adjacent pairs of channels at an integral multiple of the frequency of said first synchronizing signal, each of said coherent harmonic video carriers being physically derived from said fundamental frequency synchronizing signal itself to maintain the harmonic frequency relationship even with drift in the fundamental so that the sum and difference beat frequency of any order which result from any beat combination of said video carriers and which fall within one of said channels will always zero beat with the video carriers thereof; d. means to combine said carriers for transmission as a single cable signal; and e. means to control the phase relationship of each of said harmonically related coherent carriers with respect to the zero phase reference of their fundamental to reduce the peak value of their vector sum in said cable signal from its maximum possible value which occurs if all of said carriers reach their peak simultaneously to thereby reduce distortion during transmission of said cable signal through said cable.

Claim 20

Apparatus as in claim 10 wherein said system frequency synchronizer comprises a source of signal having a fixed fundamental freQuency and a harmonic generator receiving said signal and having an output comprising a plurality of harmonics of said synchronizing signal.

Claim 21

Apparatus as in claim 11 wherein: a. said program signal source comprises a modulator and means to apply a locally generated program as an input to said modulator; and b. said frequency relationship establishing means comprises means to select one of the harmonics from the output of said system frequency synchronizer as a carrier to be modulated in said modulator.

Claim 22

Apparatus as in claim 11 wherein: a. said program signal source comprises a modulator and means to apply as an input to said modulator the output of a demodulator which is connected to demodulate a received broadcast television signal; and b. said frequency relationship establishing means comprises means to select one of the harmonics from the output of said system frequency synchronizer to apply as a carrier input to be modulated in said modulator.

Claim 23

Apparatus as in claim 11 wherein: a. said program signal source comprises a modulator and means to apply a demodulated received broadcast television signal as a modulating input thereto; and b. said frequency relationship establishing means comprises a phaselock circuit slaving the output of said modulator to a coherent frequency relationship with a selected one of the harmonics of the output of said system frequency synchronizer.

Claim 24

Apparatus as in claim 11 wherein: a. said program signal source comprises a heterodyne intermediate frequency signal processing circuit including a down converter for converting a received television broadcast signal to a predetermined intermediate frequency; and b. said frequency relationship establishing means comprises an upconverter for converting said intermediate frequency to a desired carrier frequency and a phaselock circuit slaving the output of said upconverter to a selected one of the harmonics of the output of said system frequency synchronizer of forcing the local oscillator signal or said upconverter to drift in offsetting synchromous relationship with the drift output of said downconverter.

Claim 25

Headend equipment for a system for distribution of a plurality of multiplexed television programs on a plurality of channels each of bandwidth fs as a single cable signal, said equipment comprising: a. a system frequency synchronizer comprising a source or signal having a fixed fundamental frequency, fs, and harmonic generator means receiving said signal and having an output comprising a plurality of harmonics or said synchronizing signal and a bus conductor to supply the output of said harmonic generator to each of said channels; b. a program signal source for each channel, said source having as its output a program modulated intermediate frequency carrier of frequency fi; c. a signal frequency translating circuit for each channel; d. first input means to supply to the signal frequency translating circuit of each channel the output frequency fi of the program signal source in that channel, and second input means comprising a first tuned amplifier connected to said bus conductor and tuned to a frequency of fi + (n + m) fs to supply to said frequency translating circuit a signal derived from a selected one of said harmonics and having a frequency fi + (n + m) fs were (n + m) is an unrestrictedly selected integer which is different for each of said channels to produce as the output of said frequency translating circuit the program modulated video carrier for that channel at a frequency (n + m) fs, each of said video carriers thus being a coherent harmonic of the synchronizing signal of frequency fs; e. means to combine said outputs of said frequency translating circuits to form said single cable signal; and f. means to control the phase relationshiP of each of said harmonically related coherent carriers with respect to the zero phase reference of the fundamental which is said synchronizing signal to reduce the peak value of their vector sum in said single cable signal from its maximum possible value which occurs if all of said carriers reach their peak simultaneously to thereby reduce distortion during transmission through said cable, said control means comprising a second tuned amplifier connected to said conductor bus in each of said channels, said second amplifier being tuned to a frequency of (n + m) fs, and adjustable phase shifter means connected between said combiner means and the output of said signal translating circuit of each of said channels, and means to measure the phase relationship between the output of said phase shifter and the output of said second tuned amplifier respectively in each of said channels.

Claim 26

Headend equipment for a system for distribution of a plurality of multiplexed television programs on a plurality of channels each of bandwidth fs as a single cable signal, said equipment comprising: a. a system frequency synchronizer comprising a source or signal having a fixed fundamental frequency, fs, and harmonic generator means receiving said signal and having an output comprising a plurality of harmonics or said synchronizing signal and a bus conductor to supply the output of said harmonic generator to each of said channels; b. a program signal source for each channel, said source having as its output a program modulated intermediate frequency carrier of frequency fi; c. a signal frequency translating circuit for each channel; d. first input means to supply to the signal frequency translating circuit of each channel the output frequency fi of the program signal source in that channel, and second input means comprising a first tuned amplifier connected to said bus conductor and tuned to a frequency of fi + (n + m) fs to supply to said frequency translating circuit a signal derived from a selected one of said harmonics and having a frequency fi + (n + m) fs were (n + m) is an unrestrictedly selected integer which is different for each of said channels to produce as the output of said frequency translating circuit the program modulated video carrier for that channel at a frequency (n + m) fs, each of said video carriers thus being a coherent harmonic of the synchronizing signal of frequency fs; e. means to combine said outputs of said frequency translating circuits to form said single cable signal; and f. means to control the phase relationshiP of each of said harmonically related coherent carriers with respect to the zero phase reference of the fundamental which is said synchronizing signal to reduce the peak value of their vector sum in said single cable signal from its maximum possible value which occurs if all of said carriers reach their peak simultaneously to thereby reduce distortion during transmission through said cable, said control means comprising a second tuned amplifier connected to said conductor bus in each of said channels, said second amplifier being tuned to a frequency of (n + m) fs, and adjustable phase shifter means connected between said combiner means and the output of said signal translating circuit of each of said channels, and means to measure the phase relationship between the output of said phase shifter and the output of said second tuned amplifier respectively in each of said channels.

Claim 27

Headend equipment for a system for distribution of a plurality of multiplexed television programs on a plurality of channels each of bandwidth fs as a single cable signal, said equipment comprising: a. a system frequency synchronizer comprising a source of signal having a fixed fundamental frequency, fs, and harmonic generator means receiving said signal and having an output comprising a plurality of harmonics of said synchronizing signal and a bus conductor to supply the output of said harmonic generator to each of said channels; b. a program signal source for each channel, said source having as its output a program modulated intermediate frequency carrier of frequency fi; c. a signal frequency translating circuit for each channel; d. first input means to supply to the signal frequency translating circuit of each channel the output at frequency fi of the program signal source in that channel; and second input means comprising an amplifier connected to said bus conductor and tuned to derive a signal of frequency (n + m) fs from said bus equal to the carrier frequency for that channel, a voltage controlled local oscillator of signal frequency fi + (n + m) fs, and mixer means connected to mix the output of said oscillator and said amplifier in a loop to phaselock said voltage control local oscillator in each of said channels to said output of said program signal source, and means to supply the output of said oscillator as said second input to said frequency translating circuit to produce as the output of said frequency translating circuit the program modulated video carrier for that channel at a frequency (n + m) fs which is coherent with said amplifier output, each of said video carriers thus being a coherent harmonic of the synchronizing signal of frequency fs; e. means to combine the outputs of said frequency translating circuit to form said single cable signal; and f. means to control the phase relationship of each of said harmonically related coherent carriers with respect to the zero phase reference of the fundamental which is said synchronizing signal to reduce the peak value of the vector sum in single cable signal from its maximum possible value which occurs if all the said carriers reach their peak simultaneously to thereby reduce distortion during transmission through said cable, said control means comprising an adjustable phase shifter means connected between said combiner means and the output of said signal frequency translating circuit in each of said channels, and means to measure the phase relationship between the output of said phase shifter and the output of said tuned amplifier.

Claim 28

Headend equipment for a system for distribution of a plurality of multiplexed television programs on a plurality of channels each of bandwidth fs as a single cable signal, said equipment comprising: a. a system frequency synchronizer comprising a source of signal having a fixed fundamental frequency, fs, and harmonic generator means receiving said signal and having an output comprising a plurality of harmonics of said synchronizing signal and a bus conductor to supply the output of said harmonic generator to each of said channels; b. a program signal source for each channel, said source having as its output a program modulated intermediate frequency carrier of frequency fi; c. a signal frequency translating circuit for each channel; d. first input means to supply to the signal frequency translating circuit of each channel the output at frequency fi of the program signal source in that channel; and second input means comprising an amplifier connected to said bus conductor and tuned to derive a signal of frequency (n + m) fs from said bus equal to the carrier frequency for that channel, a voltage controlled local oscillator of signal frequency fi + (n + m) fs, and mixer means connected to mix the output of said oscillator and said amplifier in a loop to phaselock said voltage control local oscillator in each of said channels to said output of said program signal source, and means to supply the output of said oscillator as said second input to said frequency translating circuit to produce as the output of said frequency translating circuit the program modulated video carrier for that channel at a frequency (n + m) fs which is coherent with said amplifier output, each of said video carriers thus being a coherent harmonic of the synchronizing signal of frequency fs; e. means to combine the outputs of said frequency translating circuit to form said single cable signal; and f. means to control the phase relationship of each of said harmonically related coherent carriers with respect to the zero phase reference of the fundamental which is said synchronizing signal to reduce the peak value of the vector sum in single cable signal from its maximum possible value which occurs if all the said carriers reach their peak simultaneously to thereby reduce distortion during transmission through said cable, said control means comprising an adjustable phase shifter means connected between said combiner means and the output of said signal frequency translating circuit in each of said channels, and means to measure the phase relationship between the output of said phase shifter and the output of said tuned amplifier.

Claim 29

Headend equipment for a system for transmission of a plurality of television programs on a plurality of channels in a single cable, each channel having the same predetermined frequency bandwidth, said equipment comprising: a. a source of synchronizing signal having a predetermined fundamental fixed frequency equal to said Frequency bandwidth of a channel; b. means to derive from said synchronizing signal a plurality of video carrier signals having frequencies which are coherent harmonics of any order without restriction of the frequency of said synchronizing signal fundamental frequency, at least one of said carrier signals being an even order harmonic of said synchronizing signal; and c. means utilizing a different one of said plurality of carrier signals to transmit a television program signal over each one of said plurality of channels, said fundamental frequency synchronizing signal thus simultaneously controlling the frequency relationships of said video carriers for said plurality of channels and setting the minimum frequency separation between the video carriers of adjacent pairs of channels at an integral multiple of the frequency of said first synchronizing signal so that sum and difference beat frequencies of any order which result from any beat combination of said video carriers and which fall within one of said channels will zero beat with the video carrier thereof.

Claim 30

Headend equipment for a system for transmission of a plurality of television programs on a plurality of channels in a single cable, each channel having the same predetermined frequency bandwidth, said equipment comprising: a. a source of synchronizing signal having a predetermined fundamental fixed frequency equal to said Frequency bandwidth of a channel; b. means to derive from said synchronizing signal a plurality of video carrier signals having frequencies which are coherent harmonics of any order without restriction of the frequency of said synchronizing signal fundamental frequency, at least one of said carrier signals being an even order harmonic of said synchronizing signal; and c. means utilizing a different one of said plurality of carrier signals to transmit a television program signal over each one of said plurality of channels, said fundamental frequency synchronizing signal thus simultaneously controlling the frequency relationships of said video carriers for said plurality of channels and setting the minimum frequency separation between the video carriers of adjacent pairs of channels at an integral multiple of the frequency of said first synchronizing signal so that sum and difference beat frequencies of any order which result from any beat combination of said video carriers and which fall within one of said channels will zero beat with the video carrier thereof.

Claim 31

Equipment as in claim 18 wherein said source of synchronizing signal has a fixed frequency of 6 MHz.

Claim 32

Headend equipment for a system for transmission of television programs on a plurality of channels in a single cable, each channel having the same predetermined frequency bandwidth, said equipment comprising: a. a system frequency synchronizer comprising a source of signal having a fixed fundamental frequency, fs, equal to said frequency bandwidth of a channel, and harmonic generator means receiving said signal and having an output comprising a plurality of harmonics of said synchronizing signal; b. a program signal source for each channel, said source having as its output a program modulated intermediate frequency carrier of frequency fi, the frequency fi being an integral multiple of the frequency fs; c. a signal frequency translating circuit for each channel; d. first input means to supply to the signal frequency translating circuit of each channel the output at frequency fi of the program signal source in the channel, and second input means to supply to said frequency translating circuit a selected one of said harmonics at a frequency fi + nfs, where n is a preselected integer, to produce as the output of said frequency translating circuit the program modulated video carrier for that channel at a frequency nfs, each of said video carries thus being a coherent harmonic of the synchronizing signal of frequency fs, and at least one of said carries being an even order harmonic thereof; and e. said intermediate frequency, fi, being smaller in numerical value that the largest of said video carrier frequencies, nfsand each of said carriers being harmonics of any order, n, even or odd without restriction, of the frequency fs, said fundamental frequency synchronizing signal, fs, thus simultaneously controlling the frequency relationships of said video carriers for said plurality of channels and setting the minimum frequency separation between the video carriers of adjacent pairs of channels at an integral multiple of the frequency of said synchronizing signal, fs, so that the sum and difference beat frequencies of any order which result from any beat combination of said video carriers, and which fall within one of said channels will zero beat with the video carrier thereof.

Claim 33

Headend equipment for a system for transmission of television programs on a plurality of channels in a single cable, each channel having the same predetermined frequency bandwidth, said equipment comprising: a. a system frequency synchronizer comprising a source of signal having a fixed fundamental frequency, fs, equal to said frequency bandwidth of a channel, and harmonic generator means receiving said signal and having an output comprising a plurality of harmonics of said synchronizing signal; b. a program signal source for each channel, said source having as its output a program modulated intermediate frequency carrier of frequency fi, the frequency fi being an integral multiple of the frequency fs; c. a signal frequency translating circuit for each channel; d. first input means to supply to the signal frequency translating circuit of each channel the output at frequency fi of the program signal source in the channel, and second input means to supply to said frequency translating circuit a selected one of said harmonics at a frequency fi + nfs, where n is a preselected integer, to produce as the output of said frequency translating circuit the program modulated video carrier for that channel at a frequency nfs, each of said video carries thus being a coherent harmonic of the synchronizing signal of frequency fs, and at least one of said carries being an even order harmonic thereof; and e. said intermediate frequency, fi, being smaller in numerical value that the largest of said video carrier frequencies, nfsand each of said carriers being harmonics of any order, n, even or odd without restriction, of the frequency fs, said fundamental frequency synchronizing signal, fs, thus simultaneously controlling the frequency relationships of said video carriers for said plurality of channels and setting the minimum frequency separation between the video carriers of adjacent pairs of channels at an integral multiple of the frequency of said synchronizing signal, fs, so that the sum and difference beat frequencies of any order which result from any beat combination of said video carriers, and which fall within one of said channels will zero beat with the video carrier thereof.

Claim 34

Equipment as in claim 20 wherein said synchronizing signal has a frequency fs 6 MHz and said intermediate frequency signal has a frequency fi 48 MHz.

Claim 35

Equipment as in claim 20 wherein each of said signal translating circuits comprises a heterodyne mixer and each of said second input means to supply the signal of frequency fi + nfs to said mixer comprises a tuned amplIfier connected to the output of said system frequency synchronizer and tuned to the frequency fi + nfs.

Claim 36

Equipment as in claim 21 and further including circuit means to phaselock said intermediate frequency carrier to one of said plurality of harmonics of said synchronizing signal having the same frequency, fi, as said carrier.

Claim 37

Equipment as in claim 21 wherein said program signal source comprises the output stage of the down converter of a heterodyne processor for a television program which has been broadcast and received.

Claim 38

Equipment as in claim 24 wherein the local oscillator of said down converter is phaselocked to a signal of frequency fi which is derived from the output of said system frequency synchronizer by an amplifier tuned to said frequency fi.

Claim 39

Equipment as in claim 21 wherein said program signal source comprises a modulator circuit for modulating a carrier with a locally produced television program.

Claim 40

Equipment as in claim 26 wherein the carrier input to said modulator is a signal of frequency fi which is derived from the output of said system frequency synchronizer by an amplifier tuned to said frequency fi.

Claim 43

A method as in claim 28 wherein said fixed fundamental frequency synchronizing signal is provided at a frequency of 6 MHz.