Suppression of radiated emission in fiscal taxi meter

This paper is based upon National Standards for EMC. For the problem that the intensity of electromagnetic radiation in the meter with the THG at 36MHz is seriously more than National Standards, by studying the theory of radiation emission and analyzing the formation mechanism of electromagnetic radiation interference, it proposes three restrain measures: 1.the improvement of the Crystal oscillator's grounding measure; 2.adding a RC filter circuit to the Crystal oscillator circuit; 3.the improvement of the tax's communication cable, solving the problem that radiation harassment the taxi meter seriously exceeds. The experimental result demonstrates that the radiation intensity of tax meter improved with the general measures meet the requirements of the national standard, making more than 32000 taxes in Tianjin install this green meter, protecting the safety of staff and normal operation of the surrounding equipment.