Patent ID: 6792254
Filing Date: 2004-09-14
Classification: H03D

Abstract:
A device for comparing amplitudes of a first and a second input signal, comprising:a product module arranged to generate data representative of powers conveyed by the two signals and compare the data in a single process, wherein the product module generates an output signal whose value is representative of a difference between mean values of squares of amplitudes of said the two input signals, and wherein the product module comprises: a first and a second transistor forming a first differential pair, a third and a fourth transistor forming a second differential pair, a fifth and a sixth transistor forming a third differential pair, each transistor being provided with a control terminal, a transfer terminal and a reference terminal,the transfer terminal of the first transistor being connected to the reference terminals of the third and fourth transistors, the transfer terminal of the second transistor being connected to the reference terminals of the fifth and sixth transistors, the control terminals of the first and third transistors being intended to receive the first input signal, the control terminals of the second and sixth transistors being intended to receive the second input signal, the control terminals of the fourth and fifth transistors being intended to receive a same reference signal, the transfer terminals of the third and fifth transistors being connected to a supply terminal via a first resistor, the transfer terminals of the fourth and sixth transistors being connected to said supply terminal via a second resistor, the product module comprising, moreover, a low-pass filter, intended to receive an input signal drawn from the transfer terminals of the third and sixth transistors, and to supply the output signal of the product module.