Amplitude-modulated tones whose modulator and carrier frequencies are non-integer multiples produce a shifted spectrum.

Evidence

In Santurette and Dau ( 2011 ), the signals were generated by multiplying a pure tone carrier with frequency fc with a half-wave rectified sine wave modulator with modulation frequency fenv and low-pass filtered by a 4th order Butterworth filter with cut-off frequency of 0.2 × fc . All signals were generated at 50 dB SPL and mixed with a TEN noise at 34 dB SPL per ERB. All fc and fenv values are indicated in Fig. 2 . When fc and fenv are not multiple from each other, this manipulation produce a shifted complex. — Dijk, Pim van, Physiology, Psychoacoustics and…, 4622