Abstract: An analog finite impulse response (AFIR) filter including at least one variable transconductance block having an input for receiving an input voltage and being adapted to sequentially apply each of a plurality of transconductance levels to the input voltage during at least one of a plurality of successive time periods to generate an output current at an output of the variable transconductance block, the at least one variable transconductance block including a plurality of fixed transconductance blocks each receiving the input voltage and capable of being independently activated to supply the output current; and a capacitor coupled to the output of the variable transconductance block to receive the output current and provide an output voltage of the filter.

Abstract: The invention concerns a biasing circuit for controlling the current flowing through a differential pair (102, 104) comprising: a first branch comprising a first resistor (306), a first transistor device (308) and a second transistor device (310) coupled in series; a second branch comprising a second resistor (312), a third transistor device (314) and a fourth transistor device (316) coupled in series, a control node of the third transistor device being coupled to a first node (324) between the first resistor and the first transistor device, and a control node of the first transistor device being coupled to a second node (322) between the second resistor and the third transistor device; and an operational amplifier (318) having an output node coupled to control nodes of the second and fourth transistor devices, said output node providing a output signal (Vc) for controlling the current flowing through said differential pair.

Abstract: The invention concerns a biasing circuit for controlling the current flowing through a differential pair (102, 104) comprising: a first branch comprising a first resistor (306), a first transistor device (308) and a second transistor device (310) coupled in series; a second branch comprising a second resistor (312), a third transistor device (314) and a fourth transistor device (316) coupled in series, a control node of the third transistor device being coupled to a first node (324) between the first resistor and the first transistor device, and a control node of the first transistor device being coupled to a second node (322) between the second resistor and the third transistor device; and an operational amplifier (318) having an output node coupled to control nodes of the second and fourth transistor devices, said output node providing a output signal (Vc) for controlling the current flowing through said differential pair.

Abstract: A biquad gain stage, as well as a Variable Gain Amplifier is disclosed. The biquad gain stage comprises a plurality of transistors as well as conductances, and capacitances, as well as current sources. The resulting variable gain amplifier comprising a plurality of biquad gain stage cascaded in series allows to filter large unwanted blockers and to amplify a small wide-band signal. Both the gain and the filtering are distributed along a signal chain comprising a series of low-noise, high-Q biquad gain stages, each with limited current consumption and low component ratios.

Abstract: An analog finite impulse response (AFIR) filter including at least one variable transconductance block having an input for receiving an input voltage and being adapted to sequentially apply each of a plurality of transconductance levels to the input voltage during at least one of a plurality of successive time periods to generate an output current at an output of the variable transconductance block, the at least one variable transconductance block including a plurality of fixed transconductance blocks each receiving the input voltage and capable of being independently activated to supply the output current; and a capacitor coupled to the output of the variable transconductance block to receive the output current and provide an output voltage of the filter.

Abstract: An analog finite impulse response filter including at least one variable transconductance block having an input for receiving an input voltage and being adapted to sequentially apply each of a plurality of transconductance levels to the input voltage during at least one of a plurality of successive time periods to generate an output current at an output of the variable transconductance block, the at least one variable transconductance block including a plurality of fixed transconductance blocks each receiving the input voltage and capable of being independently activated to supply the output current; and a capacitor coupled to the output of the variable transconductance block to receive the output current and provide an output voltage of the filter.

Abstract: A differential biquad filter includes positive and negative single ended circuits connected between first and second power supply terminals. Each single ended circuit includes a single input terminal; a transistor having a control terminal, and first and second main terminals; a single output terminal corresponding to the control terminal of the transistor; first and second conductances connected between the single input terminal and the control terminal of the transistor; a first capacitance connected between the control terminal of the transistor and the second main terminal of the other single ended circuit; and a second capacitance connected between the node between the first and second conductances on one hand and the second main terminal of the transistor on the other hand. The differential biquad filter also includes a fifth capacitance connected between the second main terminals of each transistor of each single ended circuit.

Abstract: A biquad gain stage, as well as a Variable Gain Amplifier is disclosed. The biquad gain stage comprises a plurality of transistors as well as conductances, and capacitances, as well as current sources. The resulting variable gain amplifier comprising a plurality of biquad gain stage cascaded in series allows to filter large unwanted blockers and to amplify a small wide-band signal. Both the gain and the filtering are distributed along a signal chain comprising a series of low-noise, high-Q biquad gain stages, each with limited current consumption and low component ratios.

Abstract: A biquad notch filter includes a first stage having first and second admittances of a first type connected between an input terminal and the control terminal of a transistor, a first current source connected between a first supply terminal and a first terminal of the transistor, a second current source connected between a second terminal of the transistor and a second supply terminal; a third admittance of a second type connected between the control terminal and the second supply terminal, a fourth admittance of a second type connected between the first admittance and the second terminal; and a second stage having a transconductance, including a fifth admittance of the first type, connected between the control terminal and an output terminal, a sixth admittance of the first type connected between the output terminal and the second supply terminal, and a connection of the first terminal to the output terminal.

Abstract: A differential biquad filter includes positive and negative single ended circuits connected between first and second power supply terminals. Each single ended circuit includes a single input terminal; a transistor having a control terminal, and first and second main terminals; a single output terminal corresponding to the control terminal of the transistor; first and second conductances connected between the single input terminal and the control terminal of the transistor; a first capacitance connected between the control terminal of the transistor and the second main terminal of the other single ended circuit; and a second capacitance connected between the node between the first and second conductances on one hand and the second main terminal of the transistor on the other hand. The differential biquad filter also includes a fifth capacitance connected between the second main terminals of each transistor of each single ended circuit.

Abstract: A biquad notch filter includes a first stage having first and second admittances of a first type connected between an input terminal and the control terminal of a transistor, a first current source connected between a first supply terminal and a first terminal of the transistor, a second current source connected between a second terminal of the transistor and a second supply terminal; a third admittance of a second type connected between the control terminal and the second supply terminal, a fourth admittance of a second type connected between the first admittance and the second terminal; and a second stage having a transconductance, including a fifth admittance of the first type, connected between the control terminal and an output terminal, a sixth admittance of the first type connected between the output terminal and the second supply terminal, and a connection of the first terminal to the output terminal.