Aspects of the present disclosure provide techniques and apparatus for current-mode analog signal filtering. An example filter circuit generally includes a current-mode amplifier. The current-mode amplifier includes a first amplifier including an input and an output; a first inverter including an input coupled to the output of the first amplifier and including an output coupled to a first feedback path, the first feedback path being coupled to a first input of the filter circuit; and a second inverter including an input coupled to the output of the first amplifier.

Methods and apparatus for filtering a signal using a current-mode filter circuit implementing source degeneration. An example filter circuit generally includes an input node; an output node; a power supply node; a first transistor comprising a drain coupled to the input node; a second transistor comprising a drain coupled to the output node and comprising a gate coupled to a gate of the first transistor; a capacitive element coupled between the drain of the first transistor and the power supply node; a first resistive element coupled between the drain and the gate of the first transistor; a first source degeneration element coupled between a source of the first transistor and the power supply node; and a second source degeneration element coupled between a source of the second transistor and the power supply node.

A filtering device includes a low-pass filter (LPF), a noise estimation circuit and a first combining circuit. The LPF receives and filters a pre-filtering signal to generate an output signal of the filtering device. The noise estimation circuit estimates an estimated noise signal according to the output signal and the pre-filtering signal. The first combining circuit subtracts the estimated noise signal from an input signal of the filtering device to generate the pre-filtering signal.

One or more systems, devices and/or methods of use provided herein relate to a baseband filter that can be used in a current-mode end-to-end signal path. The current-mode end-to-end signal path can include a digital to analog converter (DAC) operating in current-mode and an upconverting mixer, operating in current-mode and operatively coupled to the DAC. In one or more embodiments, a device used in the signal path can comprise a baseband filter that receives an input current and outputs an output current. The baseband filter can comprise a feedback loop component having an active circuit branch and a passive circuit branch coupled in a loop. A mirroring device can be coupled to the feedback loop component and can provide an output of the device. Selectively activating the mirroring device can vary gain, such as of the mirroring device.