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AssigneeHitachi, Ltd.
InventorsMichitaka Osawa, Etuo Funada, Hiroyuki Miyajima, Hitoshi Maekawa, Kunio Ando
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An amplitude-adjusting circuit used for a contrast-adjusting circuit of resistor division type in which a video signal is applied across a pair of series-connected resistors and an output is produced from the junction point of the two resistors. At least one of the resistors is used as a variable resistor. The amplitude-adjusting circuit comprises a current source for supplying a constant current steadily between the terminals of the variable resistor, a high-gain amplifier for controlling the resistance value of the variable resistor, and a filter for separating the video signal component from the change of the value of the variable resistor represented by a voltage change, and introducing the resistance change to the high-gain differential amplifier.
An amplitude-adjusting apparatus comprising a signal input terminal supplied with a signal, a control terminal supplied with a control voltage, a signal output terminal for producing an amplitude-set signal in accordance with the control voltage, signal divider means including first and second impedance elements for dividing the signal applied to said input terminal, signal transmission means for introducing the input signal divided by the signal divider means to said signal output terminal, DC current supply means for supplying a DC current to at least one of the first and second impedance elements, and control means including a first input terminal connected to said control terminal and a second input terminal supplied with the DC voltage generated across one of the impedance elements for controlling the impedance value of one of said impedance elements in such a manner as to depress the voltage difference between the first and second input terminals.
An amplitude-adjusting apparatus comprising:
An amplitude-adjusting apparatus for a plurality of signal transmitters each comprising a signal input terminal supplied with a signal, a signal output terminal for producing an amplitude-adjusted signal, signal divider means including first and second impedance elements for dividing said signal applied to said input terminal, signal transmission means for introducing said input terminal signal divided by said signal divider means to said signal output terminal, DC current supply means for supplying a DC current to at least one of the first and second impedance elements, and control means including a first input terminal supplied with a control voltage and a second input terminal supplied with the DC voltage generated across one of the impedance elements for controlling the impedance value of one of said impedance elements in such a manner as to depress the voltage difference between the first and second input terminals, said apparatus comprising variable DC voltage means for supplying same variable DC voltage to said first input terminals of control means of all signal transmitters.
An amplitude-adjusting apparatus comprising:
Dependencies are inferred from the claim text.