A method for measuring a value of a predetermined characteristic of an input signal having a predetermined sign, the input signal being applied to an input terminal of an amplification device, the amplification device further including a preamplifier, an intermediate terminal, an amplification stage and an output terminal,
- the preamplifier being connected between the input terminal and the intermediate terminal,
- the amplification stage being connected between the intermediate terminal and the output terminal,
- the preamplifier being configured to apply a preliminary gain to the input signal to generate an intermediate signal to be delivered to the intermediate terminal,
- the preliminary gain being a non-null real number
- the amplification stage comprising:
- a switch including an output connected to the output terminal, a first input and a second input, the switch being configured to switch between a first position, in which the output is connected to the first input, and a second position, in which the output is connected to the second input;
- a first branch connected between the intermediate terminal and the first input of the switch, the first branch being configured to apply a first gain to the intermediate signal in order to generate a first amplified signal to be delivered to the first input of the switch;
- a second branch connected between the intermediate terminal and the second input of the switch, the second branch being configured to apply a second gain to the intermediate signal in order to generate a second amplified signal to be delivered to the second input of the switch;
- a controller configured to control switching of the switch:
- in the first position to apply the first amplified signal to the output terminal, if the value of a predetermined quantity of the first amplified signal belongs to a predetermined range, the first amplified signal forming an output signal;
- in the second position to apply the second amplified signal to the output terminal, if the value of the predetermined quantity of the first amplified signal is outside the predetermined range, the second amplified signal forming the output signal;
- the first gain and the second gain being non-null real numbers having opposite signs,
- the method including the steps of:
- measuring the value of the predetermined quantity of the output signal;
- calculating the value of the predetermined characteristic of the input signal, the value of the predetermined characteristic of the input signal being equal:
- if the input signal is positive, to:
- the value of the predetermined quantity of the output signal divided by the preliminary gain and by the first gain, if the value of the predetermined quantity of the output signal is of the same sign as the product of the preliminary gain and the first gain;
- the value of the predetermined quantity of the output signal divided by the preliminary gain and by the second gain, if the value of the predetermined quantity of the output signal is not of the same sign as the product of the preliminary gain and the first gain;
- if the input signal is negative, to:
- the value of the predetermined quantity of the output signal divided by the preliminary gain and by the first gain, if the value of the predetermined quantity of the output signal is not of the same sign as the product of the preliminary gain and the first gain;
- the value of the predetermined quantity of the output signal divided by the preliminary gain and by the second gain, if the value of the predetermined quantity of the output signal is of the same sign as the product of the preliminary gain and the first gain.