Signal processing device with a level adapter circuit
First Claim
1. An attenuator for a signal processing device including an operational amplifier having a signal input terminal, an inverting virtual reference potential input terminal, a signal output terminal and a system reference potential terminal, the amplification factor of said operational amplifier being determined by the ratio of first and second impedances, said first impedance disposed between said signal input terminal and said inverting virtual reference potential input terminal of said operational amplifier, said inverting virtual reference potential input terminal operating as a virtual reference voltage terminal and said second impedance disposed between said inverting input terminal of said operational amplifier and said signal output terminal thereof,said first impedance comprising at least two resistors, each said resistor having first and second terminals, said first terminals being connected together and to said inverting virtual reference potential input terminal andswitch means to couple selected ones of said second terminals of said resistors to said system reference potential terminal.
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Accused Products
Abstract
A signal processing device having a level adapter circuit, in particular a broad band oscilloscope, having an operational amplifier with an amplification factor determined by the ratio of a first resistor between the signal input and the inverting input of the operational amplifier--the virtual ground--and a second resistor between the inverting input of the operational amplifier and the signal output, in which the resistors may optionally be complex, in which at least one parallel resistor is provided for the first resistor, the first terminal of which is firmly connected to the signal input or a connecting point of a plurality of partial resistors forming the first resistor, and the second terminal of which can be switched over between the inverting input of the operational amplifier, which input forms the virtual ground, and the real reference potential for the amplifier input.
45 Citations
17 Claims
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1. An attenuator for a signal processing device including an operational amplifier having a signal input terminal, an inverting virtual reference potential input terminal, a signal output terminal and a system reference potential terminal, the amplification factor of said operational amplifier being determined by the ratio of first and second impedances, said first impedance disposed between said signal input terminal and said inverting virtual reference potential input terminal of said operational amplifier, said inverting virtual reference potential input terminal operating as a virtual reference voltage terminal and said second impedance disposed between said inverting input terminal of said operational amplifier and said signal output terminal thereof,
said first impedance comprising at least two resistors, each said resistor having first and second terminals, said first terminals being connected together and to said inverting virtual reference potential input terminal and switch means to couple selected ones of said second terminals of said resistors to said system reference potential terminal.
Specification