Controllable rf broadband and amplifier with a constant input impedance
AssigneeThomson Licensing
InventorsHeinrich Schemmann, Mehmet Ipek, Sabine Roth
Life of this patent
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Abstract
A variable-gain RF amplifier arrangement whose input impedance is essentially independent of the selected gain is proposed, which has a large number of selectable elementary amplifiers, with an input signal being scaled and the input impedance being set to be the same by means of switchable current limiting elements upstream of the elementary amplifiers, which are associated with the elementary amplifiers. The circuit also has a low noise level, which is largely independent of the selected gain, and good linearity. A broadcast radio receiver as well as a receiver for receiving data signals using an amplifier according to the invention are also proposed.
Claims15
An amplifier arrangement with a variable gain factor having at least two elementary amplifiers connected in parallel, wherein the input of each elementary amplifier has associated to it individual current-limiting means which are coupled to switching means for selectively invoking one of the elementary amplifiers, and which current-limiting means scale the input signal fed to the respective associated elementary amplifier and wherein an input impedance which remains essentially the same independent of the respective selected elementary amplifier can be set by means of the current-limiting means.
10-14. (canceled)
Dependencies are inferred from the claim text.