US 7,030,936 B2Granted

Pedestal level control circuit and method for controlling pedestal level

AssigneeMatsushita Electric Industrial Co., Ltd.

InventorMasahiko Sasada

Life of this patent

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Abstract

In order to reduce a circuit scale such as a brightness adjustment circuit or the number of pins in an IC chip, in the brightness adjustment circuit, a brightness adjusted video signal (internal video signal) output from an analog signal synthesis circuit or a D/A converter is input to one input terminal of a switch and a sample/hold circuit. The sample/hold circuit holds a voltage of a level in accordance with the pedestal level of the internal video signal at a timing in accordance with a sampling pulse in synchronization with the internal video signal. A clamp circuit clamps the pedestal level of an external video signal in accordance with a clamp pulse, using the voltage held by the sample/hold circuit as the reference voltage, and input it to the other input terminal. The output terminal of the switch is connected to an amplifier.

Claims9

Dependent claims

A pedestal level control circuit comprising:

video data signal output means for outputting a digital video data signal;
pedestal level adjustment data signal output means for outputting a pedestal level adjustment data signal used to generate an analog video signal having a predetermined pedestal level;
and
video signal generating means for generating the analog video signal having the predetermined pedestal level based on the video data signal and the pedestal level adjustment data signal,
wherein a plurality of sets, each set including the video data signal output means, the pedestal level adjustment data signal output means and the video signal generating means, are provided,
wherein three sets, each set including the video data signal output means, the pedestal level adjustment data signal output means and the video signal generating means, are provided, the three sets corresponding to video images of red, green and blue, respectively, and
wherein the pedestal level adjustment data signal is a brightness and cutoff adjustment data signal for performing brightness adjustment commonly to the video images of the three colors and performing cutoff adjustment for video images independently for each color.

4 more elements

Dependencies are inferred from the claim text.

Facts

Application: 10/184,952Filed 1 Jul 2002
Priority: JP 2001-2005392 Jul 2001
Published: US 2003/0001976 A12 Jan 2003
Granted: 18 Apr 2006
Term ends: Not estimatedThe source records don’t support an estimate.

Classification7 codes

H04N 5/57
Receiver circuitry for the reception of television signals according to analogue transmission standards: control of contrast or brightness
H04N 5/16
Picture signal circuitry for video frequency region: circuitry for reinsertion of DC and slowly varying components of signal; Circuitry for…
H04N 9/73
Circuits for processing colour signals: colour balance circuits, e.g. white balance circuits or colour temperature control
H04N 21/426
Structure of client; Structure of client peripherals: internal components of the client ; Characteristics thereof