Drift compensation

1. A method associated with an electric circuit manufactured in accordance with a predefined electric circuit design and defining a frequency response between an input signal and an output signal in a frequency range, the method comprising:

ii) defining, based on measurements on a test lot of other electric circuits also manufactured in accordance with the electric circuit design, a design-specific model for the electric circuit design, the design-specific model describing a frequency response of the electric circuit design in dependence of at least one parameter affecting operation of the electric circuit design; and

for the electric circuit:

iii-1) obtaining a unit-specific frequency response as a frequency response for the electric circuit measured at a certain value of the at least one parameter;

iii-2) fitting the design-specific model at said certain value of the at least one parameter to said unit-specific frequency response, whereby a unit-specific model for the electric circuit is obtained describing a frequency response for the electric circuit in dependence of the at least one parameter; and

iii-3) storing, in association with the electric circuit, data representing the unit-specific model such that the electric circuit is operable in conjunction with a compensation stage, which is configured to retrieve said data representing the unit-specific model, determine a present value of the at least one parameter and, based on said present value and said unit-specific model, compensate a deviation between a frequency response of said electric circuit and a reference frequency response, wherein the reference frequency response is independent of the at least one parameter.

2. The method of claim 1 , further comprising a preceding step of:

i) measuring N frequency responses for a test lot of other electric circuits manufactured in accordance with the electric circuit design, wherein each frequency response is measured at a certain value of the at least one parameter and the certain values of the at least one parameter are distributed over a parameter range.

3. The method of claim 1 , wherein temperature is one of the at least one parameters.

4. The method of claim 1 , wherein:

the electric circuit is configured to be powered by a supply voltage; and

a voltage of the supply voltage is one of the at least one parameters.

5. The method of claim 1 , wherein:

the electric circuit is configured for use with a preamplifier; and

a gain of said pre-amplifier is one of the at least one parameters.

6. The method of claim 1 , wherein step iii-2 includes determining a unit-specific calibration term approximating a deviation between, on the one hand, the design-specific model at said certain value of the at least one parameter and, on the other hand, the unit-specific frequency response.

7. The method of claim 6 , wherein the unit-specific model is a sum of three independent contributions:

a unit-independent frequency response;

a unit-independent compensation term, which varies with the at least one parameter; and

the unit-specific calibration term.

8. The method of claim 1 , further comprising operating the electric circuit in conjunction with a further electric circuit also manufactured in accordance with the electric circuit design, wherein the reference frequency response is a frequency response of said further electric circuit.

9. The method of claim 8 , wherein:

the electric circuit is an analog-to-digital converter; and

the operating the electric circuit and the further electric circuit includes operating as parallel components of a time-interleaved analog-to-digital conversion system.

10. The method of claim 9 , wherein temperature and supply voltage for powering the electric circuit are the at least one parameter.

11. The method of claim 8 , wherein:

the electric circuit is an analog-to-digital converter;

the operating the electric circuit and the further electric circuit includes operating when arranged in parallel branches of an in-phase/quadrature, modulator or I/Q demodulator; and

the compensation stage is an I/Q mismatch compensator.

12. The method of claim 11 , wherein:

a preamplifier is arranged in each branch upstream of a respective one of said electric circuit and said further electric circuit; and

temperature and a gain state of the preamplifiers are the at least one parameter.

13. The method of claim 1 , wherein:

the electric circuit is an analog-to-digital converter, the input signal being an analog signal and the output signal being a digital electric signal;

the reference frequency response is unit-independent;

the analog-to-digital converter is configured to be powered by a supply voltage; and

the at least one parameters are a voltage of the supply voltage and temperature.

14. The method of claim 2 , wherein the data stored in step iii-3 represents the unit-specific model in terms of a difference or a ratio with respect to said reference frequency response.

15. The method of claim 1 , wherein the electric circuit is a semiconductor circuit, preferably an integrated circuit.

16. A signal processing device comprising:

an electric circuit manufactured in accordance with a predefined electric circuit design;

a memory storing data representing a unit-specific model for the electric circuit, the unit-specific model describing a frequency response between an input signal and an output signal of the electric circuit, in a frequency range, in dependence of at least one parameter affecting operation of the electric circuit; and

a compensation stage configured

to retrieve said data from the memory,

to determine a present value of the at least one parameter, and,

based on said present value and said unit-specific model, to compensate a deviation between a frequency response of said electric circuit and a reference frequency response, wherein the reference frequency response is independent of the at least one parameter,

wherein the memory stores at least data of a first type and data of a second type representing the unit-specific model,

said first type having been prepared on the basis of a plurality of frequency responses measured for a test lot of other electric circuits also manufactured in accordance with the electric circuit design, and

said second type having been prepared on the basis of a measurement of a unit-specific frequency response for the electric circuit at a certain value of the at least one parameter.

17. The signal processing device of claim 16 , wherein the compensation stage comprises a sensor for measuring the at least one parameter.

18. A method of operating an electric circuit manufactured in accordance with a predefined electric circuit design, the method comprising:

obtaining data representing a unit-specific model for the electric circuit, the unit-specific model describing a frequency response between an input signal and an output signal of the electric circuit, in a frequency range, in dependence of at least one parameter affecting operation of the electric circuit;

determining a present value of the at least one parameter; and

based on said present value and said unit-specific model, compensating a deviation between a frequency response of said electric circuit and a reference frequency response, wherein the reference frequency response is independent of the at least one parameter,

wherein said data includes data of a first type and data of a second type,

said first type having been prepared on the basis of a plurality of frequency responses measured for a test lot of other electric circuits also manufactured in accordance with the electric circuit design, and

said second type having been prepared on the basis of a measurement of a unit-specific frequency response for the electric circuit at a certain value of the at least one parameter.

19. The method of claim 18 , wherein the data represents the unit-specific model as a formula, and said step of compensating a deviation between a frequency response of said electric circuit and a reference frequency response includes evaluating the formula for said present value of the at least one parameter.