To determine the phase velocity of the charge-density-wave (CDW) voltage noise and ${}_{}{}^{87}{}_{}{}^{}\mathrm{Rb}$ NMR spectra at an electric field of about 15$E_T$ were measured together with I-V characteristics on a ${\mathrm{Rb}}_{0.3}$${\mathrm{MoO}}_3$ crystal between 40 and 60 K. NMR spectra are reproduced by means of a velocity distribution determined by the noise spectrum. A ratio of the average noise frequency to $j_{\mathrm{CDW}}$ between 12.8 and 17.7 kHz/A⋅${\mathrm{Cm}}^{\mathrm{-}2}$ and a ratio of the average local-field oscillation frequency to $j_{\mathrm{CDW}}$ of 11±1 kHz/A⋅${\mathrm{cm}}^{\mathrm{-}2}$ are found, values close to 12.5 kHz/A⋅${\mathrm{cm}}^{\mathrm{-}2}$ from the electron density. NMR sidebands show that local-field oscillations are coherent.

• Received 6 April 1987

DOI:https://doi.org/10.1103/PhysRevLett.59.2348