Device for producing a signal having a substantially temperature-independent frequency

A device for generating a first signal having a first frequency, including:

• first generator means for generating a second signal having a second frequency which varies at least substantially parabolically as a function of the temperature with a first quadratic coefficient, which has a first maximum value at a first inversion temperature, and which has a first determined value at a reference temperature;
• second generator means for generating a third signal having a third frequency which also varies at least substantially parabolically as a function of the temperature with a second quadratic coefficient, different from said first quadratic coefficient, which has a second maximum value at a second inversion temperature, at least substantially equal to said first inversion temperature;
• and which has a second determined value at said reference temperature;
• and
• mixer means for generating a fourth signal having a fourth frequency equal to the difference between said third and said second frequency;
• said first and said second generator means being arranged so that the ratio between said first and said second quadratic coefficient is at least substantially equal to the ratio between said second and said first determined value, and so that said fourth frequency is equal to the product of said first frequency by an integer number equal to or greater than 1,
• wherein the ratio between said second and said first determined value is substantially equal to an integer number.