US 3,945,033 A · Color eliminating circuit

Abstract

A color eliminating circuit comprises a killer detection circuit, a band amplifier circuit and a control circuit. The killer detection circuit detects a color burst signal in a chromatic signal applied to an input thereof, and delivers a killer output voltage to the band amplifier circuit. When the killer output voltage is higher than a predetermined operating voltage of the band amplifier circuit, the band amplifier circuit amplifies the chromatic signal supplied thereto; when the killer voltage is lower than the operating voltage, the band amplifier circuit does not amplify the chromatic signal. The control circuit provides a gate pulse for the detection of the color burst signal, which pulse is applied to a further input of the killer detection circuit. When the killer voltage is below the operating voltage of the band amplifier circuit, the control circuit interrupts the provision of the gate pulse, to prevent the killer voltage from being supplied from the killer detection circuit. Thus, where the field strength of received signals is extremely low, an increase in the killer voltage due to noise, which might inadvertently operate the band amplifier circuit, is avoided.

Claims13

Dependent claims

A color eliminating circuit for use in a color television system comprising:

an amplifier circuit for gating a color signal and subjecting the color signal to controlled amplification;
a killer detection circuit, connected to said amplifier circuit, for controlling the action of gating and amplification of said amplifier circuit;
and
means, connected to said killer detection circuit and responsive to the level of a received color signal, for causing said killer detection circuit to cut-off the operation of said amplifier circuit when either the level of a received color signal fails to exceed a prescribed level or in the absence of receiving a color signal and the killer detection output of said killer detection circuit exceeds a prescribed operating voltage of said amplifier circuit.

1 more element

A color eliminating circuit for use in a color television system comprising:

detection circuit means for detecting a color burst signal in a chromatic signal and issuing a killer output voltage representative thereof in response to a gate pulse being applied thereto;
amplifier means, connected to said detection circuit means and having a predetermined operating voltage, for subjecting the chromatic signal to controlled amplification in response to said killer output voltage, said amplifier means amplifying the chromatic signal only when said killer output voltage is higher than said operating voltage;
and
control means, connected to said detection circuit means and responsive to an input signal representative of the level of said color burst signal, for generating said gate pulse applied to said detection circuit means only when the level of said input signal exceeds a predetermined DC voltage level.

1 more element

Dependencies are inferred from the claim text.

Color eliminating circuit

Life of this patent

Color eliminating circuit

Life of this patent

Abstract

Claims13