Noise detecting circuit for television receivers and the like

Claim 2

A noise detecting circuit for television receivers comprising; a first transistor; a second transistor; a constant current circuit connected to the emitters of said first and second transistors for maintaining constant the sum of the emitter currents of said first and second transistors; means for supplying composite video signals to the base of said first transistor; DC voltage generating means for supplying a DC voltage whose value is proportional to the peak value of synchronizing signals contained in said composite video signals to the base of said second transistor; means for taking out noise from one of the collectors of said first and second transistors when noise whose amplitude is greater than said DC voltage is supplied to the base of said second transistor.

Claim 3

A noise detecting circuit for television receivers comprising; composite video signal generating means for generating composite video signals; a synchronizing signal separator having a first terminal connected to said composite video signal generating means for supplying with video signals, a second terminal for taking out synchronizing signals therefrom and a third terminal; DC voltage generating means connected to said third terminal of said separator for generating a DC voltage whose value is proportional to the peak value of said synchronizing signals; a pair of transistors whose emitters are connected together, and the base of the first transistor in said pair being connected to said composite video signal generating means for supplying with said composite video signals and the base of the second transistor in said pair being connected to said DC voltage generating means for supplying with said DC voltage; means for taking out noise from one of the collectors of said first and said second transistors in said pair when noise whose amplitude is greater than said DC voltage is supplIed to the base of the first transistor.

Claim 4

A noise detecting circuit for television receivers comprising; composite video signal generating means for generating composite video signals; a synchronizing signal separator having a first terminal connected to said composite video signal generating means for supplying with video signals, a second terminal for taking out synchronizing signals therefrom and a third terminal; DC voltage generating means connected to said third terminal of said separator for generating a DC voltage whose value is proportional to the peak value of said synchronizing signals; a pair of transistors whose emitters are connected together, and the base of the first transistor in said pair being connected to said composite video signal generating means for supplying with said composite video signals and the base of the second transistor in said pair being connected to said DC voltage generating means for supplying with said DC voltage; means for taking out noise from one of the collectors of said first and said second transistors in said pair when noise whose amplitude is greater than said DC voltage is supplIed to the base of the first transistor.

Claim 5

A noise detecting circuit for television receivers comprising; a video amplifier for amplifying composite video signals; a synchronizing signal separator having a first terminal which is connected to said video amplifier for supplying with composite video signals, a second terminal for taking out synchronizing signals therefrom and a third terminal; DC voltage generating means connected to said third terminal of said separator for generating a DC voltage whose value is proportional to the peak value of said synchronizing signals; a pair of transistors whose emitters are connected to a constant current circuit so as to maintain constant the sum of the emitter current in said pair, and the base of the first transistor in said pair being connected to said video amplifier for supplying with, said composite video signals, and the base of the second transistor in said pair being connected to said DC voltage generating means for supplying with said DC voltage; means for taking out a pulse from one of the collectors of said first and said second transistors when noise whose amplitude is greater than said DC voltage is supplied to the base of said first transistor.

Claim 6

A noise detecting circuit for television receivers comprising; a video amplifier for amplifying composite video signals; a synchronizing signal separator having a first terminal which is connected to said video amplifier for supplying with composite video signals, a second terminal for taking out synchronizing signals therefrom and a third terminal; DC voltage generating means connected to said third terminal of said separator for generating a DC voltage whose value is proportional to the peak value of said synchronizing signals; a pair of transistors whose emitters are connected to a constant current circuit so as to maintain constant the sum of the emitter current in said pair, and the base of the first transistor in said pair being connected to said video amplifier for supplying with, said composite video signals, and the base of the second transistor in said pair being connected to said DC voltage generating means for supplying with said DC voltage; means for taking out a pulse from one of the collectors of said first and said second transistors when noise whose amplitude is greater than said DC voltage is supplied to the base of said first transistor.

Claim 7

A noise detecting circuit for television receivers comprising; a video amplifier for amplifying composite video signals; a synchronizing signal separator having a first terminal which is connected to said video amplifier for supplying with composite video signals, a second terminal for taking out synchronizing signals therefrom and a third terminal; DC voltage generating means connected to said third terminal of said separator for generating a DC voltage whose value is proportional to the peak value of said synchronizing signals; a pair of transistors whose emitters are connected to a constant current circuit so as to maintain constant the sum of the emitter current in said pair, and the base of the first transistor in said pair being connected to said video amplifier for supplying with said composite video signals, and the base of the second transistor in said pair being connected to said DC voltage generating means for supplying with said DC voltage; means for taking out a pulse for from the collector of said first transistor when noise whose amplitude is greater than said DC voltage is supplied to the base of the said first transistor in said pair; a noise inverter which is connected between said second terminal of said separator and a power source being responsive to said pulse supplied from the collector of said first transistor in the pair so as to cancel noise generated to said second terminal of said separator.

Claim 8

A noise detecting circuit for television receivers comprising; a video amplifier for amplifying composite video signals; a synchronizing signal separator having a first terminal which is connected to said video amplifier for supplying with composite video signals, a second terminal for taking out synchronizing signals therefrom and a third terminal; DC voltage generating means connected to said third terminal of said separator for generating a DC voltage whose value is proportional to the peak value of said synchronizing signals; a pair of transistors whose emitters are connected to a constant current circuit so as to maintain constant the sum of the emitter current in said pair, and the base of the first transistor in said pair being connected to said video amplifier for supplying with said composite video signals, and the base of the second transistor in said pair being connected to said DC voltage generating means for supplying with said DC voltage; means for taking out a pulse for from the collector of said first transistor when noise whose amplitude is greater than said DC voltage is supplied to the base of the said first transistor in said pair; a noise inverter which is connected between said second terminal of said separator and a power source being responsive to said pulse supplied from the collector of said first transistor in the pair so as to cancel noise generated to said second terminal of said separator.

Claim 9

A noise detecting circuit for television receivers comprising; a video amplifier for amplifying composite video signals; a synchronizing signal separator having a first terminal which is connected to said video amplifier for supplying with composite video signals, a second terminal for taking out synchronizing signals therefrom and a third terminal; DC voltage generating means connected to said third terminal of said separator for generating a DC voltage whose value is proportional to the peak value of said synchronizing signals; a pair of transistors whoes emitters are connected to a constant current circuit so as to maintain constant the sum of the emitter current in said pair, and the base of the first transistor in said pair being connected to said video amplifier for supplying with said composite video signals and the base of the second transistor in said pair being connected to said DC voltage generating means for supplying with said DC voltage; means for taking out a pulse for from the collector of said second transistor when noise whose amplitude is greater than said DC voltage is supplied to the base of said first transistor; a first noise inverter which is connected between an input terminal of an automatic gain controlling cirCuit which is connected to said video amplifier and ground being responsive to said pulse so as to cancel noise contained in said composite video signals supplied to said automatic gain controlling circuit.

Claim 10

A noise detecting circuit for television receivers comprising; a video amplifier for amplifying composite video signals; a synchronizing signal separator having a first terminal which is connected to said video amplifier for supplying with composite video signals, a second terminal for taking out synchronizing signals therefrom and a third terminal; DC voltage generating means connected to said third terminal of said separator for generating a DC voltage whose value is proportional to the peak value of said synchronizing signals; a pair of transistors whoes emitters are connected to a constant current circuit so as to maintain constant the sum of the emitter current in said pair, and the base of the first transistor in said pair being connected to said video amplifier for supplying with said composite video signals and the base of the second transistor in said pair being connected to said DC voltage generating means for supplying with said DC voltage; means for taking out a pulse for from the collector of said second transistor when noise whose amplitude is greater than said DC voltage is supplied to the base of said first transistor; a first noise inverter which is connected between an input terminal of an automatic gain controlling cirCuit which is connected to said video amplifier and ground being responsive to said pulse so as to cancel noise contained in said composite video signals supplied to said automatic gain controlling circuit.

Claim 11

A noise detecting circuit for television receivers comprising; a video amplifier for amplifying composite video signals; a synchronizing signal separator having a first terminal which is connected to said video amplifier for supplying with video signals, a second terminal for taking out said synchronizing signals therefrom and a third terminal; DC voltage generating means connected to said third terminal of said separator for generating a DC voltage whose value is proportional to the peak value of said synchronizing signals; a pair of transistors whose emitters are connected to a constant current circuit so as to maintain constant the sum of the emitter current in said pair, and the base of the first transistor in said pair being connected to said video amplifier for supplying with said composite video signals, and the base of the second transistor in said pair being connected to said DC voltage generating means for supplying with said DC voltage; means for taking out a first and second pulse from the collector of said first transistor and the collector of said second transistor respectively when noise whose amplitude is greater than said DC voltage is supplied to the base of said first transistor in said pair; a first noise inverter which is connected between said second terminal of said separator and a power supply being responsive to said first pulse supplied from the collector of said first transistor so as to cancel noise generated in said first terminal of said separator; a second noise inverter which is connected between an input terminal of an automatic gain controlling circuit which is connected to said video amplifier and ground being responsive to said second pulse so as to cancel noise contained in said composite video signals which are supplied to said automatic gain controlling circuit.

Claim 12

A noise detecting circuit for television receivers comprising; a video amplifier for amplifying composite video signals; a synchronizing signal separator having a first terminal which is connected to said video amplifier for supplying with video signals, a second terminal for taking out said synchronizing signals therefrom and a third terminal; DC voltage generating means connected to said third terminal of said separator for generating a DC voltage whose value is proportional to the peak value of said synchronizing signals; a pair of transistors whose emitters are connected to a constant current circuit so as to maintain constant the sum of the emitter current in said pair, and the base of the first transistor in said pair being connected to said video amplifier for supplying with said composite video signals, and the base of the second transistor in said pair being connected to said DC voltage generating means for supplying with said DC voltage; means for taking out a first and second pulse from the collector of said first transistor and the collector of said second transistor respectively when noise whose amplitude is greater than said DC voltage is supplied to the base of said first transistor in said pair; a first noise inverter which is connected between said second terminal of said separator and a power supply being responsive to said first pulse supplied from the collector of said first transistor so as to cancel noise generated in said first terminal of said separator; a second noise inverter which is connected between an input terminal of an automatic gain controlling circuit which is connected to said video amplifier and ground being responsive to said second pulse so as to cancel noise contained in said composite video signals which are supplied to said automatic gain controlling circuit.

Claim 13

A noise detecting circuit for television receivers as claimed in claim 6 wherein said first constant current circuit including a fourth transistor whose base is supplied with a constant voltage; said second constant current circuit including a fifth transistor whose base is supplied with a constant voltage.

Claim 14

A noise detecting circuit for television receivers comprising; a first transistor for amplifying composite video signals supplied from a video detector to the base of said transistor; a second transistor for separating synchronizing signals from said composite video signals which are supplied to the base of said second transistor; DC voltage generating means which are connected between the emitter of said second transistor and ground including a capacitor and a first constant current circuit connected in parallel for generating a DC voltage whose value is proportional to the peak value of said synchronizing signals; a pair of transistors whose emitters are connected to ground through a second constant current circuit so as to maintain constant the sum of the emitter current in said pair, and the base of said first transistor in said pair being connected to the emitter of said first transistor through a voltage divider for supplying with said composite video signals and the base of said second transistor in said pair being connected to the emitter of said second transistor for supplying with said DC voltage; means for taking out a pulse from the collector of said first transistor in said pair when noise whose amplitude is greater than said DC voltage is supplied to the base of said first transistor in said pair; a noise inverter connected between the collector of said second transistor and a power supply including a third transistor whose base is connected to the collector of said first transistor in said pair so as to cancel noise generated to the collector of said second transistOr when said pulse is supplied to the base of said third transistor.

Claim 15

A noise detecting circuit for television receivers comprising; a first transistor for amplifying composite video signals supplied from a video detector to the base of said transistor; a second transistor for separating synchronizing signals from said composite video signals which are supplied to the base of said second transistor; DC voltage generating means which are connected between the emitter of said second transistor and ground including a capacitor and a first constant current circuit connected in parallel for generating a DC voltage whose value is proportional to the peak value of said synchronizing signals; a pair of transistors whose emitters are connected to ground through a second constant current circuit so as to maintain constant the sum of the emitter current in said pair, and the base of said first transistor in said pair being connected to the emitter of said first transistor through a voltage divider for supplying with said composite video signals and the base of said second transistor in said pair being connected to the emitter of said second transistor for supplying with said DC voltage; means for taking out a pulse from the collector of said first transistor in said pair when noise whose amplitude is greater than said DC voltage is supplied to the base of said first transistor in said pair; a noise inverter connected between the collector of said second transistor and a power supply including a third transistor whose base is connected to the collector of said first transistor in said pair so as to cancel noise generated to the collector of said second transistOr when said pulse is supplied to the base of said third transistor.

Claim 16

A noise detecting circuit for television receivers comprising; a first transistor for amplifying composite video signals supplied from a video detector to the base of said transistor; a second transistor for separating synchronizing signals from said video signals which are supplied to the base of said second transistor; DC voltage generating means which is connected between the emitter of said second transistor and ground including a capacitor and a first constant current circuit connected in parallel for generating a DC voltage whose value is proportional to the peak value of said synchronizing signals; a pair of transistors whose emitters are connected to ground through a second constant current circuit so as to maintain constant the sum of the emitter current in said pair, and the base of said first transistor in said pair being connected to the emitter of said first transistor through a voltage divider for supplying with said composite video signals and the base of said second transistor in said pair being connected to the emitter of said second transistor for supplying with said DC voltage; means for taking out a first and second pulse from the collector of said first transistor in said pair and the collector of said second transistor in said pair respectively when noise whose amplitude is greater than said DC voltage is supplied to the base of said first transistor in said pair; a noise inverter connected between the collector of said second transistor and a power supply including a third transistor whose base is connected to the collector of said first transistor in said pair so as to cancel noise generated in the collector of said second transistor; a second noise inverter connected between an input terminal of an automatic gain controlling circuit which is connected to the emitter of said first transistor and ground including a fourth transistor whose base is connected to the collector of said second transistor in said pair for cancelling noise contained in said video signal supplied from said first transistor to said automatic gain controlling circuit;

Claim 17

A noise detecting circuit for television receivers comprising; a first transistor for amplifying composite video signals supplied from a video detector to the base of said transistor; a second transistor for separating synchronizing signals from said video signals which are supplied to the base of said second transistor; DC voltage generating means which is connected between the emitter of said second transistor and ground including a capacitor and a first constant current circuit connected in parallel for generating a DC voltage whose value is proportional to the peak value of said synchronizing signals; a pair of transistors whose emitters are connected to ground through a second constant current circuit so as to maintain constant the sum of the emitter current in said pair, and the base of said first transistor in said pair being connected to the emitter of said first transistor through a voltage divider for supplying with said composite video signals and the base of said second transistor in said pair being connected to the emitter of said second transistor for supplying with said DC voltage; means for taking out a first and second pulse from the collector of said first transistor in said pair and the collector of said second transistor in said pair respectively when noise whose amplitude is greater than said DC voltage is supplied to the base of said first transistor in said pair; a noise inverter connected between the collector of said second transistor and a power supply including a third transistor whose base is connected to the collector of said first transistor in said pair so as to cancel noise generated in the collector of said second transistor; a second noise inverter connected between an input terminal of an automatic gain controlling circuit which is connected to the emitter of said first transistor and ground including a fourth transistor whose base is connected to the collector of said second transistor in said pair for cancelling noise contained in said video signal supplied from said first transistor to said automatic gain controlling circuit;

Claim 18

A noise detecting circuit for television receivers as claimed in claim 9 wherein said first constant current circuit including a fifth transistor whose base is supplied with a constant voltage; said second constant current circuit including a sixth transistor whose base is supplied with a constant voltage.