In the previous scheme temporal resolution was limited by two factors:
the fixed size of the FFT window and the variable size (1/*F*_{0}) of the
smoothing window. Slightly better resolution could be obtained by
setting the FFT window itself to 1/*F*_{0} (with a square window), and
removing the subsequent temporal smoothing stage. In practice, the
signal must be resampled so the period 1/*F*_{0} fits a power of two.
After the FFT, the spectrum must be resampled.

Advantages of this scheme are: (a) Voice-related fluctuations in the time-domain are removed perfectly, at the smallest possible cost in terms of temporal resolution. (b) Voice-related ripple of the spectrum is also eliminated. The spectral envelope is accurately described by the spectrum produced by the FFT. (c) There are no window artefacts.

The scheme also has disadvantages. Resampling the waveform and
spectrum introduces an extra computational cost. More troublesome,
much more accurate *F*_{0} estimation is required. A small error in *F*_{0}
estimation will cause the zeros of the integration window to be
shifted in a way that can severely distort the spectrum in the high
frequency region. A subharmonic error (doubling or tripling of the
period estimate, hard to avoid) will introduce zero-amplitude
coefficients in the spectrum (which will look spiky rather than
smooth). This interferes with spectral resampling.