Logarithmic detector amplifier system for use as high sensitivity selective receiver without frequency conversion

摘要

A logarithmic detector amplifying (LDA) system is provided for use as a high sensitivity receive booster or replacement for a low noise amplifier in a receive chain of a communication device. The LDA system includes an amplifying circuit configured to receive an input signal having a first frequency and generate an oscillation based on the input signal, a sampling circuit coupled to the amplifying circuit and configured to terminate the oscillation based on a predetermined threshold to periodically clamp and restart the oscillation to generate a series of pulses modulated by the oscillation and by the input signal, and one or more resonant circuits coupled with the amplifying circuit and configured to establish a frequency of operation and to generate an output signal having a second frequency, the second frequency being substantially the same as the first frequency.

主权项

1. A system for use in a receive chain of a communication device, the system comprising:
a logarithmic amplifying circuit configured to receive an input signal at an input of the system having a first frequency and to generate an oscillation based on the input signal; a sampling circuit coupled to the logarithmic amplifying circuit and configured to:
compare an input signal magnitude of the input signal with a predetermined input signal magnitude threshold; andterminate the oscillation when the input signal magnitude is equal to or greater than the predetermined input signal magnitude threshold so as to periodically clamp and restart the oscillation to generate a series of voltage spikes; a first resonant circuit coupled to the logarithmic amplifying circuit and configured to establish a frequency of operation of the system; and a second resonant circuit coupled to at least one of the first resonant circuit or the logarithmic amplifying circuit and configured to generate an output signal at an output of the system having a second frequency, the second frequency being substantially the same as the first frequency, wherein the output signal is generated without frequency conversion of the input signal.