A signal processing device includes an acoustic echo cancellation (AEC) circuit, a blocking matrix circuit, a controller, a subtractor, and a filter. The AEC circuit performs an AEC operation based on a far-end signal and a first input signal to generate a processed signal. The blocking matrix circuit suppresses a target signal component of the first input signal and a second input signal, to generate a reference signal. The controller generates a control coefficient based on the processed signal and the second input signal. The subtractor generates an output signal based on the filtered signal and the processed signal. The filter generates the filtered signal in response to the control coefficient, the reference signal, and the output signal.