We focus on our recent study of coherent phonons in wide-gap semiconductors. The principle and advantage of spectrally filtered EO sampling pump-probe transmittance detection of coherent phonons in transparent media are explained. Even though using noncollinear optical parametric amplifier with low repetition rate, we could clearly observe the coherent phonon signal. We studied resonant generation of coherent phonon in ZnTe by a nondegenerate pump-probe measurement. The pump energy dependence of the initial amplitude can be explained by the intense absorption of the pump pulse.