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US 2010/0188172 A1Published application
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AssigneeThales
InventorMarc Pouplier
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AssigneeThales
InventorMarc Pouplier
Estimating the term…
The invention relates to a bandpass filter comprising at least one first oscillating circuit formed of inductive means (L1, L2) in parallel with capacitive means (Cij) and of a second oscillating circuit comprising inductive means (L3, L4) arranged in parallel with capacitive elements (Cij), the first oscillating circuit being coupled to the second oscillating circuit, characterized in that the capacitive means (Cij1) of the first oscillating circuit comprise a variable assembly of capacitive elements (C11, C12, C13, C14) in series with a fixed capacitor (C1) and in that the capacitive elements of the second oscillating circuit comprise an assembly of variable capacitive elements (C21, C22, C23, C24) arranged in series with a fixed capacitor (C2) and in that the first oscillating circuit and the second oscillating circuit are coupled by means of capacitive elements of substantially fixed value (C3, C4) and in that the capacitive coupling elements are linked to the midpoint (P1, P2) of two variable capacitive elements.
1- A bandpass filter comprising at least one first oscillating circuit formed of inductive means (L1, L2) in parallel with capacitive means (Cij) and of a second oscillating circuit comprising inductive means (L3, L4) arranged in parallel with capacitive elements (Cij), the first oscillating circuit being coupled to the second oscillating circuit, characterized in that the capacitive means (Cij1) of the first oscillating circuit comprise a variable assembly of capacitive elements (C11, C12, C13, C14) in series with a fixed capacitor (C1) and in that the capacitive elements of the second oscillating circuit comprise an assembly of variable capacitive elements (C21, C22, C23, C24) arranged in series with a fixed capacitor (C2) and in that the first oscillating circuit and the second oscillating circuit are coupled by means of capacitive elements of substantially fixed value (C3, C4) and in that the capacitive coupling elements are linked to the midpoint (P1, P2) of two variable capacitive elements.
2- The filter as claimed in claim 1, characterized in that a variable capacitive element (C11′) mounted in series with the fixed capacitor comprises several variable capacitors mounted in parallel (C111′, C112′).
3- The filter as claimed in claim 1, characterized in that it comprises two oscillating circuits.
4- A filtering device characterized in that it comprises a filter with several poles (n) as claimed in one of claims 1 to 3 and in that it comprises independent controls for each pole.
5- A filtering device comprising at least one filter as claimed in one of claims 1 to 3 and characterized in that it comprises at least one operational amplifier (21), a negative feedback circuit (22), the negative feedback circuit (22) comprising a resistor (Rc) having a value substantially identical to the value of the bias resistance R of the variable capacitive elements of the filter and a resistor (Rp) having a value substantially identical to the value of the resistance R and a first capacitive assembly Cc1 having a value identical to that of C11 and a second capacitive assembly Cc2 whose value is identical to that of the value of C12.