Circuit for the compensation of the horizontal component of the earth's magnetic field for a color picture tube of a high-resolution monitor
AssigneeU.S. Philips Corporation
InventorsGiovanni Lonoce, Carlo Negretti
Life of this patent
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Abstract
The circuit includes a probe (6) for detecting a horizontal magnetic field and a first and a second circuit means (15, 17) driven by said probe (6) so as to create respective axial and lateral components of compensation of the horizontal magnetic field, that are in the same direction and of equal intensity, but of opposite sign to that of the magnetic field under test.
Claims9
Circuit for the compensation of the horizontal component of the earth's magnetic field for a color picture tube of a picture display apparatus, wherein said circuit includes a probe for detecting a horizontal magnetic field, and first and second circuit means driven by said probe so as to create respective axial and lateral components of compensation of the horizontal magnetic field, that are in the same direction and of equal intensity, but of opposite sign to that of the magnetic field under test, and wherein the second circuit means comprises a pair of demagnetization coils connected electrically in parallel and associated with an internal magnetic screen applied to the picture tube to produce said lateral component of compensation of the magnetic field under test, characterized in that said circuit comprises signal detection means coupled to the output of the probe for forming a control impulse for a demagnetization circuit formed by an oscillator including said demagnetization coils and supplied from a rechargeable source of continuous voltage.
Circuit for the compensation of the horizontal component of the earth's magnetic field for a color picture tube of a picture display apparatus, wherein said circuit includes a probe for detecting a horizontal magnetic field, and first and second circuit means driven by said probe so as to create respective axial and lateral components of compensation of the horizontal magnetic field, that are in the same direction and of equal intensity, but of opposite sign to that of the magnetic field under test, characterized in that the probe comprises a bridge-circuit with at least one resistance which is magnetic field dependent, said bridge having a pair of H-Vo characteristics.
Circuit for the compensation of the horizontal component of the earth's magnetic field for a color picture tube of a picture display apparatus, wherein said circuit includes a probe for detecting a horizontal magnetic field, and first and second circuit means driven by said probe so as to create respective axial and lateral components of compensation of the horizontal magnetic field, that are in the same direction and of equal intensity, but of opposite sign to that of the magnetic field under test, and wherein the second circuit means comprises a pair of demagnetization coils connected electrically in parallel and associated with an internal magnetic screen applied to the picture tube to produce said lateral component of compensation of the magnetic field under test, characterized in that said circuit further includes a processing unit for processing an output signal from said probe, said processing unit comprising a preamplifier having inputs for receiving the signal from the probe and an output coupled to an input of a signal switching unit, said signal switching unit having a second input which receives a reference voltage and outputs coupled with inputs of a differential amplifier, an output of said differential amplifier forming an output of said processing unit.
Dependencies are inferred from the claim text.