Demodulating logarithmic amplifier
AssigneeYuantonix, Inc.
InventorKevin Gamble
Life of this patent
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Abstract
A demodulating logarithmic amplifier rectifies a radio frequency signal prior to amplification through progressive stages. A full wave linear or squaring rectifier receives a waveform signal at the input and provides a rectified signal that is proportional to an envelope or a square of the envelope of the waveform signal at the output. The rectified signal is then fed to a series of limiting amplifier stages where the signal is progressively amplified. After each individual amplifier stage, the partially amplified signal is passed through a voltage-to-current converter to create a current signal. All the current signals are subsequently summed to produce an amplified current output signal that is representative of the logarithm of the envelope of the input signal.
Claims13
A demodulating logarithmic amplifier, comprising:
- a full wave rectifier, having an input for receiving a waveform signal and an output for providing a rectified signal that is proportional to an envelope of the waveform signal;
- a plurality of serially coupled amplifier stages, each having an input and an output, wherein the input of a first amplifier stage is coupled to the full wave rectifier to receive the rectified signal;
- a plurality of voltage-to-current converters, each having an input and an output, the input coupled to an output of a respective one of the plurality of serially coupled amplifier stages;
- wherein the outputs of each of the plurality of voltage-to-current converters are coupled together;
- and
- wherein the values of at least two or more of the plurality of voltage-to-current amplifiers are not identical.
A demodulating logarithmic amplifier, comprising:
- means for rectifying, having an input for receiving a waveform signal and an output for providing a rectified signal that is proportional to an envelope of the waveform signal;
- a first means for amplifying the rectified signal, coupled to the output of the means for rectifying;
- first converting means, coupled to the first means for amplifying, for converting the amplified signal from voltage to current;
- second through Nth means for amplifying, where N is an integer greater than 2, serially coupled to the first means for amplifying and to each other;
- second through Nth converting means, where N is an integer greater than 2, coupled to the respective second through Nth means for amplifying, for converting the respective amplified signals from voltage to current;
- means for summing all of the converted current signals to provide an amplified current output, and;
- wherein the value of the first converting means is not identical to a value of one or more of the second through Nth converting means.
Dependencies are inferred from the claim text.