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US 4,972,512 AGranted
Circuit for linearly amplifying and demodulating an AM-modulated signal, and integrated semiconductor element for such circuit
AssigneeU.S. Philips Corporation
InventorArnoldus Garskamp
Life of this patent
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Abstract
Circuit arrangement for linearly amplifying and demodulating an AM-modulated signal, and integrated semiconductor element for said circuit arrangement. A linear amplifier and demodulator for AM-modulated signals comprises a logarithmic amplifier having a number of amplifier stages successively operating in a limiting mode, an antilog circuit, and DC separation between the logarithmic amplifier and the antilog circuit.
Claims11
A circuit for linearly amplifying and demodulating an AM-modulated signal, comprising:
- a logarithmic amplifier comprising a plurality of limiting amplifier stages which successively operate in a limiting mode in response to an increase of the input signal, a demodulation circuit for each limiting amplifier stage, and an adder circuit which is common for all stages, the logarithmic amplifier having an input for receiving the AM-modulated signal and an output for supplying a demodulated, logarithmically distorted output signal;
- an antilog circuit having an input connected to the output of the logarithmic amplifier for substantially compensating the logarithmic distortion of the output signal of the logarithmic amplifier and for supplying the demodulated AM signal;
- and
- DC isolation means for preventing a DC component of the output signal of the logarithmic amplifier from being applied to the input of the antilog circuit.
1 more element
Dependencies are inferred from the claim text.