We present theoretical analysis and numerical calculations for the generation of high harmonics and ultrashort pulses driven by midinfrared lasers.Our calculations are based on a framework,in which the process of harmonic generation is computed via an extension of the strong-field approximation on the microscopic level and macroscopically,the gas medium is then discretized into elementary radiators and the radiation(harmonic emission) of each of these sources is propagated to the detector and calculated as coherent sum.