Methods and spectrometers for carrying out ion-cyclotron-resonance spectrometry are described in which a pulse sequence is employed which is described by P1-t1-P2-Tm-P3-t2, (P1, P2, and P3 are radio-frequency pulses, with P1 and P2 having the same frequency; t1 and Tm are time intervals between the pulses; and t2 is the observation time following the last pulse); the sequence is repeated several times while varying t1 to obtain a plurality of induction signals during t2, from which a 2-dimensional spectrum may be derived by transformation from the time to the frequency domain. The transformation may be accomplished by 2-dimensional Fourier transformation or by the method of max. entropy. [on SciFinder (R)]