A digital playback signal detection apparatus includes a phase equalization circuit for compensating and correcting for loss of a low frequency band and phase distortion in the playback signal, respectively, a waveform shaper for correcting the waveform generated by the phase equalization circuit, and a data detector for detecting the originally recorded data using an output signal of the waveform shaper and a phase-inverted version thereof. The output of the phase equalizer circuit is delayed into first and second delay signals using two delays. The second delay signal and the output signal of the phase equalizer are amplified and differentiated, and then the differentiated signal and first delay signal are linearly added to each other. According to one aspect of the invention, the data detector compensates for loss of low-frequency band from a signal reproduced from a magnetic recording medium via an integrator in a phase equalizer. According to another aspect of the invention, a limiter is connected to the output of the differentiator in the waveform shaper while two limiters are connected to the output of a buffer included in the data detector. Accordingly, the distortion and noise of the input signal is removed and the error rate associated with data-detection can be decreased while the data is stably detected, even if the tape has degenerated or the system is unstable. A method for particularly adapted to the signal detection apparatus is also described.