The technique under proposal for a precise spectrum analysis within an algorithm of the collinear wave heterodyning implies a twostage integrated processing, namely, the wave heterodyning of a signal in a square-law nonlinear medium and then the optical processing in the same solid state cell. The technical advantage of this approach lies in providing a direct multichannel parallel processing of ultra-high-frequency radio-wave signals with essentially improved frequency resolution. This technique imposes specific requirements on the cell’s material. We focus our attention on the solid solutions of thallium chalcogenides and take the TIBr–TII (thallium bromine–thallium iodine) solution, which forms KRS–5 cubic-symmetry crystals with the mass-ratio 58% of TIBr to 42% of TII. Analysis shows that the acousto-optical cell made of a KRS–5 crystal oriented along the [111]-axis and the corresponding longitudinal elastic mode for producing the dynamic diffractive grating can be exploited. With the acoustic velocity of about 1.92 × 10⁵ cm/s and attenuation of ∼10 dB/(cm GHz²), a similar cell is capable of providing an optical apertura of ∼5.0 cm and one of the highest figures of acousto-optical merit in solid states in the visible range. Such a cell is rather desirable for the application to direct 5000-channel parallel spectrum analysis with an improved up to 10⁻⁵ relative frequency resolution. ©2011 Society of Photo-Optical Instrumentation Engineers (SPIE). [DOI: 10.1117/1.3549892]