Paper deals with digital generating quadrature wave, their measurement and monitoring using Lab View virtual instrumentation system. Beside classical triangular digital quadrature oscillator there are investigated rectangular- and meander-type waveforms and also three-phase Clarke transformed orthogonal waveforms. There is shown — using digital computation of total harmonic distortion — that meander-type quadrature waves reache minimum THD equal 5 %. The block scheme of virtual implementation of those system using LabView is given.