Pay television system

Claim 2

Method of encoding a composite television signal having a video signal with a determined black level signifying picture black, and synchronizing signals having a determined synchronizing level and polarity relative to said black level, for reception on receiving means requiring a predetermined minimum pulse width for synchronization, comprising, in combination, the steps of generating a sequence of reference pulses having a polarity opposite to said synchronizing polarity and a pulse width less than said predetermined minimum pulse width, each displaced by a determined time interval from a corresponding one of said synchronizing signals; combining said reference pulses with said composite television signal, thereby creating a second television signal; generating a video carrier signal; and modulated said video carrier signal with said second television signal in such a manner that said reference pulse is transmitted at substantially peak transmitter power, said somodulated video carrier signal constituting a transmitter signal.

Claim 3

A method as set forth in claim 1 wherein each of said reference pulses has a reference pulse amplitude, said transmitter signal having a reference level corresponding to said reference pulse amplitude; further comprising the step of clamping said transmitter signal to said reference level.

Claim 4

A method as set forth in claim 1, wherein said composite television signal has an associated program audio signal; further comprising the step of furnishing an encoder audio carrier signal, and modulating said program audio signal on said encoder audio carrier signal in such a manner that a suppressed carrier signal is furnished.

Claim 5

A method as set forth in claim 3, further comprising the step of furnishing a barker audio signal; and combining said barker audio signal with said suppressed carrier signal.

Claim 6

A method as set forth in claim 1, wherein said synchronizing signals comprise horizontal synchronizing pulses and vertical synchronizing pulses; and wherein said step of generating a sequence of reference pulses comprises the step of generating a reference pulse in response to each of said horizontal synchronizing pulses.

Claim 7

A method as set forth in claim 5, wherein said synchronizing signals comprise horizontal synchronizing pulses, and vertical synchronizing pulses; wherein said step of generating a sequence of reference pulses comprises the step of generating a reference pulse in response to each of said horizontal synchronizing pulses in such a manner that the trailing edge of a reference pulse substantially coincides in time with the leading edge of a corresponding one of said horizontal synchronization pulses.

Claim 8

A method as set forth in claim 5, further comprising the step of generating video inverter signals independent of said reFerence pulses; and inverting said video signal in response to each of said video inverter signals.

Claim 9

A method as set forth in claim 7 wherein said composite television signal comprises a vertical blanking interval; and wherein generating video inverter signals comprises generating noise signals randomly having a first or second polarity; sampling said noise signals during said vertical blanking; interval and generating a video inverter signal in response to a so-sampled noise signal of first polarity.

Claim 10

A method as set forth in claim 8, wherein inverting said video signal in response to each of said video inverter signals comprises inverting said video signal for the subsequent field of said composite television signal.

Claim 11

A method as set forth in claim 9, further comprising the step of generating an encoding burst in response to each of said video inverter signals; and combining said encoding burst with said composite television signal.

Claim 12

A method as set forth in claim 10, further comprising the step of generating horizontal blanking pulses.

Claim 13

A method as set forth in claim 11, wherein combining said encoding burst with said composite television signal comprises inserting said encoding burst between the trailing edge of a selected horizontal blanking pulse and the leading edge of the reference pulse subsequent to said selected horizontal blanking pulse during said vertical blanking interval, thereby furnishing a final transmitter signal.

Claim 14

A method as set forth in claim 12, further comprising the step of transmitting said final transmitter signal.

Claim 15

A method as set forth in claim 13, further comprising the step of receiving and demodulating said final transmitter signal.

Claim 16

A method as set forth in claim 14, further comprising the step of separating said reference pulse and said encoding burst from said demodulated signal.

Claim 17

A method as set forth in claim 15, further comprising the step of generating an AGC signal corresponding to the amplitude of said so-separated reference pulse.

Claim 18

A method as set forth in claim 16, further comprising the step of reinverting said video signal during the field immediately subsequent to a so-separated encoding burst thereby furnishing a composite television signal having a decoded video signal.

Claim 19

A method as set forth in claim 17, further comprising the step of furnishing a second carrier signal; and modulating said composite television signal having said decoded video signal onto said second carrier signal, thereby furnishing a standard television signal.

Claim 20

Method of encoding a composite television signal having a video signal portion and having vertical blanking intervals, comprising, in combination, the step of generating a video inverter signal during a randomly selected one of said vertical blanking intervals of said composite television signal; inverting only said video portion of said composite television signal throughout the field following generation of said video inverter signal; generating an encoding signal; and inserting said encoding signal into said composite television signal in response to said video inverter signal, thereby creating an encoded composite television signal wherein the presence of said encoding signal indicates inversion of said video portion throughout the subsequent field.

Claim 21

Method of encoding a composite television signal having a video signal portion and having vertical blanking intervals, comprising, in combination, the step of generating a video inverter signal during a randomly selected one of said vertical blanking intervals of said composite television signal; inverting only said video portion of said composite television signal throughout the field following generation of said video inverter signal; generating an encoding signal; and inserting said encoding signal into said composite television signal in response to said video inverter signal, thereby creating an encoded composite television signal wherein the presence of said encoding signal indicates inversion of said video portion throughout the subsequent field.

Claim 22

A pay television system, comprising, in combination, standard composite television signal furnishing means for furnishing a composite television signal having a plurality of fields, each of said fields comprising a plurality of lines, vertical synchronizing signals, horizontal synchronizing signals, and a video signal with a determined black level signifying picture black; inverting and non-inverting amplifier means each having an input connected to said standard composite television signal furnishing means, each of said amplifier means further having an output; connecting means directly connecting the output of said non-inverting amplifier means to thE output of said inverting amplifier means; synchronizing signal separator means having a first sync output furnishing horizontal synchronizing pulses and a second sync output furnishing vertical synchronizing pulses; gating generator means having a first output connected to said non-inverting amplifier means and a second output connected to said inverting amplifier means for selectively enabling each of said amplifier means during determined portions of said composite television signal, said gating generator means further comprising counter means having a counting input connected to said first sync output and a reset input connected to said second sync output, said counting means furnishing counting signals each corresponding to the number of one of said lines within one of said fields; reference pulse generator means connected to said synchronizing signal separator means for furnishing a reference pulse in response to each of said so-separated horizontal synchronizing pulses and at a determined time instance relative thereto; and first circuit means for inserting said reference pulses into said composite television signal.

Claim 23

A pay television system, comprising, in combination, standard composite television signal furnishing means for furnishing a composite television signal having a plurality of fields, each of said fields comprising a plurality of lines, vertical synchronizing signals, horizontal synchronizing signals, and a video signal with a determined black level signifying picture black; inverting and non-inverting amplifier means each having an input connected to said standard composite television signal furnishing means, each of said amplifier means further having an output; connecting means directly connecting the output of said non-inverting amplifier means to thE output of said inverting amplifier means; synchronizing signal separator means having a first sync output furnishing horizontal synchronizing pulses and a second sync output furnishing vertical synchronizing pulses; gating generator means having a first output connected to said non-inverting amplifier means and a second output connected to said inverting amplifier means for selectively enabling each of said amplifier means during determined portions of said composite television signal, said gating generator means further comprising counter means having a counting input connected to said first sync output and a reset input connected to said second sync output, said counting means furnishing counting signals each corresponding to the number of one of said lines within one of said fields; reference pulse generator means connected to said synchronizing signal separator means for furnishing a reference pulse in response to each of said so-separated horizontal synchronizing pulses and at a determined time instance relative thereto; and first circuit means for inserting said reference pulses into said composite television signal.

Claim 24

An arrangement as set forth in claim 20, wherein said counting means comprises binary counting means having a plurality of counting stages.

Claim 25

An arrangement as set forth in claim 20, further comprising noise signal generating means furnishing noise signals randomly having a first or second polarity; and wherein said gating generator means comprises means sampling said noise signals and generating a video inverter signal in response to a so-sampled noise signal of first polarity, whereby said video inverter signal is generated in a substantially random manner.

Claim 26

An arrangement as set forth in claim 22, wherein said sampling means comprises first flip-flop means having a set and reset input; and switch means connecting the output of said noise signal generating means to said set input of said first flip-flop means in response to a first selected one of said counting signals.

Claim 27

An arrangement as set forth in claim 23, further comprising means connecting said reset input of said first flip-flop means to said counting means for resetting said flip-flop in response to a second selected one of said counting signals.

Claim 28

An arrangement as set forth in claim 24, further comprising reset burst generator means for furnishing a reset burst; and reset gating means connecting said reset burst generator means to said output of said inverting and non-inverting amplifier means in response to said second selected one of said counting signals.

Claim 29

An arrangement as set forth in claim 25, wherein said composite television signal comprises vertical blanking intervals; and wherein said second selected one of said counting signals is the counting signal corresponding to the line immediately preceeding said vertical blanking interval, whereby said reset burst is inserted into said composite television signal immediately prior to each of said vertical blanking intervals.

Claim 30

An arrangement as set forth in claim 26, further comprising horizontal blanking signal generator means furnishing horizontal blanking signals; and wherein said gating generator means comprises first logic circuit means furnishing a timed second selected counting signal in response to said second selected one of said counting signals in the absence of said reference pulse and said horizontal blanking signal.

Claim 31

An arrangement as set forth in claim 27, wherein said reset input of said first flip-flop means and said reset gating means are connected to the output of said first logic circuit means.

Claim 32

An arrangement as set forth in claim 28, further comprising first and second coding signal generator means; first and second gate means respectively connecting said first or second coding signal generator means to said output of said inverting and non-inverting amplifier in response to a first and second coding enable signal; and means furnishing said first and second coding enable signal in response to a third selected one of said counting signals and, respectively, said set and reset state of said first flip-flop means.

Claim 33

An arrangement as set forth in claim 29, further comprising polarity flip-flop means having a set input and a reset input, said polarity flip-flop means further having a ''''1'''' output in response to a signal at said set input and a ''''0'''' output in response to a signal at said reset input; second logic circuit means furnishing a signal to said set input of said polarity flip-flop means in response to the simultaneous presence of set state in said first flip-flop means and a fourth selected one of said counting signals; and means directly connecting the reset input of said polarity flip-flop means to the reset input of said first flip-flop means.

Claim 34

An arrangement as set forth in claim 30, further comprising third logic circuit means connected between said reference pulse generator means, said horizontal blanking generator means, said polarity flip-flop means and said first output of said gating generator means for furnishing a signal energizing said non-inverting amplifier means in the presence of said ''''0'''' output of said polarity flip-flop means, or the presence of said horizontal blanking signal, simultaneously with the absence of said reference pulse and said second selected one of said counting signals.

Claim 35

An arrangement as set forth in claim 30, further comprising fourth logic circuit means interconnected between said polarity flip-flop means, said reference pulse generator means, said horizontal blanking generator means and said second output of said gating generator means, for furnishing a signal enabling said inverter amplifier means in the presence of said ''''1'''' output of said polarity flip-flop means and the simultaneous absence of said reference pulse and said horizontal blanking signal.

Claim 36

Pay television transmitting system for transmitting a television signal for reception on receiving means requiring a predetermined minimum pulse width of synchronization, comprising, in combination, standard composite television signal furnishing means for furnishing a composite television signal having a video signal with a determined black level signifying picture black; synchronizing signal separator means for separating horizontal synchronizing signals from said composite television signal; reference pulse generator means connected to said synchronizing signal separator means for furnishing a reference pulse having a pulse width less than said predetermined minimum pulse width in response to each of said so-operated horizontal synchronizing pulses and at a determined time instant relative thereto; and circuit means for inserting said reference pulses into said composite television signal.

Claim 37

Pay television transmitting system for transmitting a television signal for reception on receiving means requiring a predetermined minimum pulse width of synchronization, comprising, in combination, standard composite television signal furnishing means for furnishing a composite television signal having a video signal with a determined black level signifying picture black; synchronizing signal separator means for separating horizontal synchronizing signals from said composite television signal; reference pulse generator means connected to said synchronizing signal separator means for furnishing a reference pulse having a pulse width less than said predetermined minimum pulse width in response to each of said so-operated horizontal synchronizing pulses and at a determined time instant relative thereto; and circuit means for inserting said reference pulses into said composite television signal.

Claim 38

Pay television system, comprising, in combination, standard composite television signal furnishing means for furnishing a composite television signal having a video signal with a determined black-level signifying picture black; synchronizing signal separator means for separating horizontal synchronizing signals from said composite television signal; reference pulse generator means connected to said synchronizing signal separator means for furnishing a reference pulse in response to each of said so-separated horizontal synchronizing pulses and at a determined time instant relative thereto; circuit means for inserting said reference pulses into said composite television signal; inverting and non-inverting amplifier means each having an input connected to said standard composite television signal furnishing means, each of said amplifier means further having an output; connecting means directly connecting the output of said non-inverting amplifier means to the output of said inverting amplifier means; and gating generator means having a first output connected to said non-inverting amplifier means and a second output connected to said inverting amplifier means for selectively enabling eaCh of said amplifier means during determined portions of said composite television signal.

Claim 39

Pay television system, comprising, in combination, standard composite television signal furnishing means for furnishing a composite television signal having a video signal with a determined black-level signifying picture black; synchronizing signal separator means for separating horizontal synchronizing signals from said composite television signal; reference pulse generator means connected to said synchronizing signal separator means for furnishing a reference pulse in response to each of said so-separated horizontal synchronizing pulses and at a determined time instant relative thereto; circuit means for inserting said reference pulses into said composite television signal; inverting and non-inverting amplifier means each having an input connected to said standard composite television signal furnishing means, each of said amplifier means further having an output; connecting means directly connecting the output of said non-inverting amplifier means to the output of said inverting amplifier means; and gating generator means having a first output connected to said non-inverting amplifier means and a second output connected to said inverting amplifier means for selectively enabling eaCh of said amplifier means during determined portions of said composite television signal.

Claim 40

An arrangement as set forth in claim 34, wherein said inverting amplifier means comprises first differential amplifier means having a first and second transistor, each of said transistors having a base, collector, and emitter; wherein said composite television signal is applied to the base of said first transistor; wherein a fixed potential is applied to the base of said second transistor; and wherein the output of said first differential amplifier is the collector of said first transistor.

Claim 41

An arrangement as set forth in claim 34, wherein said gating generator means comprises means enabling said non-inverting amplifier means during all horizontal and vertical blanking intervals of said composite television; and wherein said gating signal generator means further comprises means enabling said inverting amplifier means only during selected ones of said video portions of said composite television signal.

Claim 42

An arrangement as set forth in claim 36, wherein said non-inverting amplifier means comprises a second differential amplifier, said second differential amplifier comprising a second and third transistor, each of said second and third transistors having a base, collector and emitter; wherein said composite television signal is applied to the base of said third transistor; means applying a fixed voltage to the base of said fourth transistor; and wherein said output of said non-inverting amplifier means is the collector of said fourth transistor.

Claim 43

An arrangement as set forth in claim 37, further comprising means furnishing a blocking potential; additional transistor means having an emitter-collector circuit connected between said means furnishing a blocking potential and a selected circuit point of said first differential amplifier means, said additional transistor means further having a base; and wherein said gating generator means comprise means blocking current flow in said base circuit of said additional transistor means to enable said first differential amplifier means.

Claim 44

An arrangement as set forth in claim 36, wherein said gating generator means comprise logic circuit means connected to said reference pulse generator means, for blocking both said inverting and non-inverting amplifier means in response to each of said reference pulses, whereby each of said reference pulses is inserted into said composite television signal.

Claim 45

Pay television system, comprising, in combination, means for furnishing an encoded television signal having a plurality of fields, inverted video signals only during selected ones of said fields, horizontal synchronizing signals, and a reference pulse associated with each of said horizontal synchronizing signals, said encoded television signal further having decoding bursts present during the vertical blanking times preceeding each of said fields having said inverted video signals; and decoding means for furnishing a standard television signal upon receipt of said encoded television signal, said decoding means comprising inverting means for inverting the video signals of the subsequent field upon receipt of one of said decoding bursts, means for separating each of said reference pulses from said encoded television signal, means for furnishing a reference pulse suppressor signal in response to each of the so-separated reference pulses, and means for applying said reference pulse suppressor signals to said composite television signal in such a manner that said reference pulses are suppressed at least in part.

Claim 46

Pay television system, comprising, in combination, means for furnishing an encoded television signal having a plurality of fields, inverted video signals only during selected ones of said fields, horizontal synchronizing signals, and a reference pulse associated with each of said horizontal synchronizing signals, said encoded television signal further having decoding bursts present during the vertical blanking times preceeding each of said fields having said inverted video signals; and decoding means for furnishing a standard television signal upon receipt of said encoded television signal, said decoding means comprising inverting means for inverting the video signals of the subsequent field upon receipt of one of said decoding bursts, means for separating each of said reference pulses from said encoded television signal, means for furnishing a reference pulse suppressor signal in response to each of the so-separated reference pulses, and means for applying said reference pulse suppressor signals to said composite television signal in such a manner that said reference pulses are suppressed at least in part.

Claim 47

Method of encoding the audio portion of a composite television signal having horizontal synchronizing pulses occurring at a horizontal synchronizing pulse frequency and having an associated program audio signal, comprising, in combination, the steps of furnishing an encoder audio carrier signal having a frequency which is an integral multiple of said horizontal synchronizing pulse frequency; modulating saiD program audio signal onto said encoder audio carrier signal in such a manner that a suppressed carrier signal is furnished; furnishing a barker audio signal; combining said barker audio signal with said suppressed carrier signal; and transmitting the so combined signals.

Claim 48

Method of encoding the audio portion of a composite television signal having horizontal synchronizing pulses occurring at a horizontal synchronizing pulse frequency and having an associated program audio signal, comprising, in combination, the steps of furnishing an encoder audio carrier signal having a frequency which is an integral multiple of said horizontal synchronizing pulse frequency; modulating saiD program audio signal onto said encoder audio carrier signal in such a manner that a suppressed carrier signal is furnished; furnishing a barker audio signal; combining said barker audio signal with said suppressed carrier signal; and transmitting the so combined signals.

Claim 49

Pay television transmitter system for transmitting an encoded television signal for reception on television receiver means requiring pulses having at least a predetermined value of a determined characteristic for synchronization, comprising, in combination, standard composite television signal furnishing means for furnishing a composite television signal having a video signal with a determined black level signifying picture black and having horizontal synchronizing pulses having a synchronizing polarity relative to said black level; synchronizing signal separator means for separating horizontal synchronizing pulses from said composite television signals; reference pulse generator means connected to said synchronizing signal separator means for furnishing a reference pulse in response to each of said so-separated horizontal synchronizing pulses and at a determined time instant relative thereto, said reference pulses having a value of said determined characteristic less than said predetermined value and a polarity opposite to said synchronizing polarity; circuit means connected to said reference pulse generator means for inserting said reference pulses into said composite television signal, thereby creating an encoded television signal; and means connected to said circuit means for transmitting said encoded television signal in such a manner that said reference pulses have said synchronizing polarity.

Claim 50

Pay television transmitter system for transmitting an encoded television signal for reception on television receiver means requiring pulses having at least a predetermined value of a determined characteristic for synchronization, comprising, in combination, standard composite television signal furnishing means for furnishing a composite television signal having a video signal with a determined black level signifying picture black and having horizontal synchronizing pulses having a synchronizing polarity relative to said black level; synchronizing signal separator means for separating horizontal synchronizing pulses from said composite television signals; reference pulse generator means connected to said synchronizing signal separator means for furnishing a reference pulse in response to each of said so-separated horizontal synchronizing pulses and at a determined time instant relative thereto, said reference pulses having a value of said determined characteristic less than said predetermined value and a polarity opposite to said synchronizing polarity; circuit means connected to said reference pulse generator means for inserting said reference pulses into said composite television signal, thereby creating an encoded television signal; and means connected to said circuit means for transmitting said encoded television signal in such a manner that said reference pulses have said synchronizing polarity.

Claim 51

An arrangement as set forth in claim 42, further comprising synchronizing signal separator means connected to said standard composite signal furnishing means for furnishing horizontal synchronizing pulses; timing circuit means furnishing a timing signal varying as a predetermined function of time following receipt of each of said horizontal synchronizing signals; and threshold means connected to said timing circuit means for furnishing said reference pulse in response to a predetermined amplitude of said timing signal.

Claim 52

An arrangement as set forth in claim 43, wherein said timing circuit means comprises capacitor means and transistor means connected in parallel with said capacitor means for discharging said capacitor means in response to each of said horizontal synchronizing signals.

Claim 53

An arrangement as set forth in claim 42, further comprising transmitter means for transmitting said composite television signal with said reference pulses in such a manner that said reference pulses are transmitted at RF power levels normally occupied by said horizontal synchronizing pulses.