Wireless circuitry can include a processor that generates a reference baseband signal, an upconversion circuit that upconverts the baseband signals to radio-frequency signals, an amplifier that amplifies the radio-frequency signals, and an antenna. The amplifier can be adjusted based on an estimated value computed using error vector magnitude (EVM) estimation circuitry. The EVM estimation circuitry may include a first filter configured to receive the reference signal, a second filter configured to receive a measured signal coupled from the output of the amplifier, a first signal extraction circuit coupled to an output of the first filter, a second signal extraction circuit coupled to an output of the second filter, and a comparison circuit having a first input that receives signals from the first signal extraction circuit, a second input that receives signals from the second signal extraction circuit, and an output on which the estimated value is provided.