When one looks at an NMR spectrum, it is almost always assumed that the spectrum is composed of the resonances of only one nuclide. There are examples where this is not the case. One of these examples is shown below. The spectrum is that of sodium orthovanadate, Na3VO4 (which also forms Na2VO3(OH) in aqueous solution). The spectrum contains the resonances of both 23Na and 51V and shows the ratio between the VO43- and [VO3(OH)]2- ions.
This spectrum was acquired on a 300 MHz spectrometer.