Abstract: The invention discloses a nonlinear feedback circuit, which includes at least one diode. The invention also discloses a low noise amplifier using the nonlinear feedback circuit. In the invention, temperature compensation is performed for the gain change of the low noise amplifier based on the negative temperature characteristics of the diode, thereby achieving gain stability. In addition, the nonlinear characteristics of the diode can also provide high-order harmonics for the low-noise amplifier, and the mutual cancellation and addition of high-order harmonics can increase the OIP3 of the low noise amplifier.

Abstract: The invention discloses a broadband logarithmic detector with high dynamic range, comprising a low noise amplifier, a compensate detection unit, a current summation and driving unit, an N-stage clipper amplifier and an N-stage detection unit. The invention improves the detection sensibility of the overall detector by adding a low noise amplifier before the first-stage clipper amplifier and extends the dynamic detection range of the overall detector through combination of the low noise amplifier and the compensate detection unit.