An integrated circuit for emulating a resistor (72, 74), comprising: a main circuit element being the main transistor having a control terminal being a gate and a source and a drain as respective input and output terminal, the resistance between the source and drain providing the emulated resistor; a high-impedance direct current, DC, gate bias circuit for biasing the main transistor into operation in its linear region; a coupling circuit for coupling a voltage dependent on the voltage between the input terminal and output terminal to the voltage applied to the control terminal, thereby to improve linearity of the current-voltage relationship between the source and drain with respect to changes in the voltage between the source and drain; wherein either a) the coupling circuit comprises a feedforward capacitor, C, connected between the gate and drain of the main transistor, and coupling a voltage dependent on the voltage between the input terminal and output terminal to the voltage applied to the control terminal comprises adding a scaled fraction of the ac source-drain voltage to the gate voltage; or b) the circuit comprises a series resistor, Rbias, in series with the drain of the main transistor, wherein the coupling circuit comprises a feed-forward capacitor and is for adding a scaled fraction of the ac source-drain voltage to the gate voltage, connected between a node of the series resistor remote from the drain and the gate of the main transistor or between the drain and the gate of the main transistor or a combination of both, and wherein the coupling circuit is for adding a voltage comprising a scaled fraction of one or more of: the alternating current, AC, source voltage of the main transistor; the AC drain voltage of the main transistor; the AC source-drain of the main transistor; the AC voltage across the series resistor. a main circuit element being the main transistor having a control terminal being a gate and a source and a drain as respective input and output terminal, the resistance between the source and drain providing the emulated resistor; a high-impedance direct current, DC, gate bias circuit for biasing the main transistor into operation in its linear region; a coupling circuit for coupling a voltage dependent on the voltage between the input terminal and output terminal to the voltage applied to the control terminal, thereby to improve linearity of the current-voltage relationship between the source and drain with respect to changes in the voltage between the source and drain; wherein either a) the coupling circuit comprises a feedforward capacitor, C, connected between the gate and drain of the main transistor, and coupling a voltage dependent on the voltage between the input terminal and output terminal to the voltage applied to the control terminal comprises adding a scaled fraction of the ac source-drain voltage to the gate voltage; or b) the circuit comprises a series resistor, Rbias, in series with the drain of the main transistor, wherein the coupling circuit comprises a feed-forward capacitor and is for adding a scaled fraction of the ac source-drain voltage to the gate voltage, connected between a node of the series resistor remote from the drain and the gate of the main transistor or between the drain and the gate of the main transistor or a combination of both, and wherein the coupling circuit is for adding a voltage comprising a scaled fraction of one or more of: the alternating current, AC, source voltage of the main transistor; the AC drain voltage of the main transistor; the AC source-drain of the main transistor; the AC voltage across the series resistor.