电子电气设备在进行射频电磁场辐射抗扰度试验中,为了保证试验的有效性和重复性,需要对场均匀性进行校准。文中介绍了场均匀性校准的要求和方法,并以80MHz^1GHz10V/m的校准场强为例,分别选择1.5m×1.5m和0.5m×0.5m两个窗口对...电子电气设备在进行射频电磁场辐射抗扰度试验中,为了保证试验的有效性和重复性,需要对场均匀性进行校准。文中介绍了场均匀性校准的要求和方法,并以80MHz^1GHz10V/m的校准场强为例,分别选择1.5m×1.5m和0.5m×0.5m两个窗口对均匀域进行校准。然后从场强分布、场强差值分布、定点场强实测等方面对这两个窗口的校准结果进行分析、对比,结果表明小窗口的场均匀性要明显优于大窗口。最后文章建议按照被测件(Equipment Under Test,简称EUT)的尺寸来选择校准窗口的大小,在窗口覆盖EUT的前提下尽量选择较小的尺寸,对于过大尺寸的EUT可采用部分照射法。这样不仅更好地保证了试验的有效性和重复性,而且还提高了场均匀性校准的效率。展开更多
Accurate assessment of herbage mass （HM） in pasture is a key to budgeting forage in grazing systems worldwide. Different non-destructive techniques to measuring pasture yield are commented. The methods compared incl...Accurate assessment of herbage mass （HM） in pasture is a key to budgeting forage in grazing systems worldwide. Different non-destructive techniques to measuring pasture yield are commented. The methods compared include visual estimations, manual and electronic pasture meters and remote sensing. All methods are associated with a moderate to high error, showing that some indirect methods of yield estimation are appropriate under most appropriate because many factors as climate variations, soil certain conditions. In general terms, no method was found as the characteristics, plant phenology, pasture management and species composition must be taken into account to make local calibrations from a general model. Best results were found modifying general methods under local calibrations and under local conditions. In order to give farmers the best method to manage adequately their own grazing systems, researchers must select the most suitable technique considering the scale of operation, the desired accuracy and the resources available.展开更多
文摘电子电气设备在进行射频电磁场辐射抗扰度试验中,为了保证试验的有效性和重复性,需要对场均匀性进行校准。文中介绍了场均匀性校准的要求和方法,并以80MHz^1GHz10V/m的校准场强为例,分别选择1.5m×1.5m和0.5m×0.5m两个窗口对均匀域进行校准。然后从场强分布、场强差值分布、定点场强实测等方面对这两个窗口的校准结果进行分析、对比,结果表明小窗口的场均匀性要明显优于大窗口。最后文章建议按照被测件(Equipment Under Test,简称EUT)的尺寸来选择校准窗口的大小,在窗口覆盖EUT的前提下尽量选择较小的尺寸,对于过大尺寸的EUT可采用部分照射法。这样不仅更好地保证了试验的有效性和重复性,而且还提高了场均匀性校准的效率。
文摘Accurate assessment of herbage mass （HM） in pasture is a key to budgeting forage in grazing systems worldwide. Different non-destructive techniques to measuring pasture yield are commented. The methods compared include visual estimations, manual and electronic pasture meters and remote sensing. All methods are associated with a moderate to high error, showing that some indirect methods of yield estimation are appropriate under most appropriate because many factors as climate variations, soil certain conditions. In general terms, no method was found as the characteristics, plant phenology, pasture management and species composition must be taken into account to make local calibrations from a general model. Best results were found modifying general methods under local calibrations and under local conditions. In order to give farmers the best method to manage adequately their own grazing systems, researchers must select the most suitable technique considering the scale of operation, the desired accuracy and the resources available.
