Method and apparatus for scrambled television

Claim 3

The method of claim 1 in which said signal of fixed selected format is formed by the steps of; a. counting pulses (226'') time related to plural field cycles of television scanning, b. passing predetermined counted pulses (as 165'''', 167'''', 169''''& 171) to a logic network, and c. forming pulses having random duration and random spacing (34'''') from the passed pulses according to predetermined logic of said logic network.

Claim 4

The method of claim 1, which additionally includes; a. receiving said carrier-wave, b. demodulating said carrier-wave, c. providing the same said signal (34) of fixed selected format by counting said first modulation component (126), and d. converting the sequences of said receiver-unuseable video and synchronizing information to be receiver-useable during said alternate intervals of said period of said signal of fixed selected format, whereby receiver-useability is obtained for all of said video and synchronizing information.

Claim 5

Apparatus for scrambling television, comprising; a. coding means (31, 32, 33) to form a signal of fixed selected format (34'''') having a selectable programmed random periodicity with respect to television scanning, and first and second modulation component pulses (226'', 227''), said signal having a selected periodicity sufficiently long to include plural field scanning cycles in each period, b. a double differential-amplifier switcher (35) connected means-for-continuously-producing (69) normal video and synchronizing information, c. gating means (33) of said coding means connected to said switcher, and having series-connected multiple counting means (150-155), first circuit-code-determining means (173), and logic elements (174, 175,), operatively connected to said counting means and effectively sequentially operable to produce random intervals (2, 3) of abnormal said video and synchronizing information according to multiples of said fixed selected format which are unuseable at a television receiver, alternately with respect to intervals of normal (8, 9) said video and synchronizing information, d. burst means (53) connected to said coding means for producing first and second modulation component bursts related to said television scanning, and randomly related in time to the beginning of means said period of said intervals of abnormal said video and synchronizing information, respectively, according to said first circuit-code-determining means (173), e. a burst-adder (65) connected to said switcher (35) and said burst means (53) to add said first and second modulation component bursts to said video and synchronizing information for operating counting means at a receiver, f. televesion transmitting means (91, 92) having a modulator (78), and g. a connection (67) between said coding means, said switcher, and said modulator, whereby successive intervals of useable and unuseable said video and synchronizing information, and said first and second modulation components are modulated upon one carrier-wave.

Claim 6

Apparatus for scrambling television, comprising; a. coding means (31, 32, 33) to form a signal of fixed selected format (34'''') having a selectable programmed random periodicity with respect to television scanning, and first and second modulation component pulses (226'', 227''), said signal having a selected periodicity sufficiently long to include plural field scanning cycles in each period, b. a double differential-amplifier switcher (35) connected means-for-continuously-producing (69) normal video and synchronizing information, c. gating means (33) of said coding means connected to said switcher, and having series-connected multiple counting means (150-155), first circuit-code-determining means (173), and logic elements (174, 175,), operatively connected to said counting means and effectively sequentially operable to produce random intervals (2, 3) of abnormal said video and synchronizing information according to multiples of said fixed selected format which are unuseable at a television receiver, alternately with respect to intervals of normal (8, 9) said video and synchronizing information, d. burst means (53) connected to said coding means for producing first and second modulation component bursts related to said television scanning, and randomly related in time to the beginning of means said period of said intervals of abnormal said video and synchronizing information, respectively, according to said first circuit-code-determining means (173), e. a burst-adder (65) connected to said switcher (35) and said burst means (53) to add said first and second modulation component bursts to said video and synchronizing information for operating counting means at a receiver, f. televesion transmitting means (91, 92) having a modulator (78), and g. a connection (67) between said coding means, said switcher, and said modulator, whereby successive intervals of useable and unuseable said video and synchronizing information, and said first and second modulation components are modulated upon one carrier-wave.

Claim 7

The apparatus of claim 4, in which the logic elements of said gating means (33) include; a. a large plurality of means responsive to the selected characteristic (160-171) of said first circuit-code determining-means (173) which determines the circuit code, and b. predetermined electrical connections (183-191) between said logic elements, whereby the time of occurrence and duration of each said interval of abnormal said video and synchronizing information is determined by both the selected characteristic of the first circuit-code determining-means and the electrical connections between said logic elements.

Claim 8

The apparatus of claim 4, in which; a. said normal video and synchronizing information has a given polarity, and said abnormal video and synchronizing information has the opposite polarity to said given polarity.

Claim 9

The apparatus of claim 4, which additionally includes; a. receiver means (103-110) to receive and demodulate (106) said carrier-wave, b. a decoder (109, 135, 140, 250, 256) connected to said receiver means, c. gating means (33'') included in said decoder, and having second circuit-code-determing means (173'') equivalent to said first circuit-code-determining means, d. a connection from said receiver means to said gating means to control said gating means in accordance with said modulation components, and e. a second double differential-amplifier switcher (35) connected to said gating means, whereby said intervals of unuseable said video and synchronizing information are rendered useable.

Claim 10

The apparatus of claim 7, in which said decoder includes; a. a nand gate (136, 137), b. first amplifying means (131) connected to said nand gate to provide a pulse (132'''') having the duration of said first modulation component, and c. second amplifying means (125) connected to said nand gate to provide pulses (128'''') having the durations of both said first and second modulation components, whereby an output pulse (140'''') from said nand gate occurs only each time a pulse having the duration of said second modulation component occurs.

Claim 11

The apparatus of claim 4, in which said coding (31, 32) and gating means (33) thereof comprise; a. a plurality of connected counters (150-155), b. plural illuminating means (172) plurally connected to said counters, c. said first circuit-code-determining means embodied as an opaque member (173) having preselected holes (163-169, etc.) aligned with selected said illuminating means, d. plural illumination-sensitive means (183-189,etc.) alIgned with said plural illuminating means, and e. plural logic means (174-178) uniquely connected to said plural illumination-sensitive means to sequentially produce an electrical output according to the illumination through said preselected holes.

Claim 12

The apparatus of claim 4, in which said switcher (35) comprises; a. a first differential amplifier (36, 37), b. a second differential amplifier (44, 46) connected to one output of said first differential amplifier, c. a third differential amplifier (45, 47) connected to the other output of said first differential amplifier, d. an output circuit (48), e. a connection from said gating means (33) to said second and third differential amplifiers, whereby a video and a synchronizing signal input to said switcher is reversed in polarity at said output circuit upon the presence of an output from said gating means.

Claim 13

The apparatus of claim 4, which additionally includes; a. amplitude shiftable clamping means (80-83) to establish a black level at said modulator (78) connected thereto, and b. bias means (79), connected to said clamping means, to shift the amplitude of said black level according to the polarity of the video and synchronizing information existing at said modulator.