Automatic switching circuit for a dual mode television receiver
First Claim
1. In a television signal receiving apparatus having red, green and blue video output stages, a first input for receiving a composite video signal and a second input for receiving an RGB signal including a sync component and red, green and blue video components, an electronic signal switching circuit comprising:
- means coupling the red, green and blue video components of the RGB signal from the second input to said red, green and blue video output stages respectively;
chroma-luma processing means for deriving red, green and blue video components from the composite video signal received at the first input;
means for coupling said derived red, green and blue video components to said red, green and blue video output stages respectively; and
composite video blanking means operable in response to the presence of the sync component of the RGB siganl at the second input for blanking said derived red, green and blue video components.
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Accused Products
Abstract
A television signal receiving apparatus having a first input for receiving a composite video signal and a second input for receiving a direct-drive RGB signal includes an electronic switching circuit for automatically switching between composite video and RGB modes of operation. The switching circuit is responsive to the presence of the sync component of an RGB signal at the second input for automatically establishing the RGB mode of operation wherein only the input RGB signal is used to form the image display and is responsive to the absence of the sync component of the RGB signal at the second input for establishing the composite video mode of operation wherein the composite video signal at the first input is used to form the image display. Provisions are included for developing an override signal for allowing the development of a mixed mode image display.
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Citations
10 Claims
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1. In a television signal receiving apparatus having red, green and blue video output stages, a first input for receiving a composite video signal and a second input for receiving an RGB signal including a sync component and red, green and blue video components, an electronic signal switching circuit comprising:
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means coupling the red, green and blue video components of the RGB signal from the second input to said red, green and blue video output stages respectively; chroma-luma processing means for deriving red, green and blue video components from the composite video signal received at the first input; means for coupling said derived red, green and blue video components to said red, green and blue video output stages respectively; and composite video blanking means operable in response to the presence of the sync component of the RGB siganl at the second input for blanking said derived red, green and blue video components. - View Dependent Claims (2, 3, 4, 5, 6)
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7. In a television signal receiving apparatus having a sync processing circuit, red, green and blue video output stages, a first input for receiving a composite video signal and a second input for receiving an RGB signal including a sync component and red, green and blue video components, an electronic signal switching circuit comprising:
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means coupling the red, green and blue video components of the RGB signal from the second input to said red, green and blue video output stages respectively; chroma-luma processing means for deriving red, green and blue video components from the composite video signal received at the first input; means for coupling said derived red, green and blue video components to said red, green and blue video output stages respectively; switching control means for developing a control signal in response to the presence of the sync component of the RGB signal at said second input; composite video blanking means responsive to said control signal for blanking said derived red, green and blue video components; and sync switching means responsive to said control signal for coupling the sync component of the RGB signal to said sync processing circuit and otherwise coupling the composite video signal from the first input to the sync processing circuit. - View Dependent Claims (8, 9, 10)
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Specification