Linearity check at 5 voltage levels on one range at the same frequency as in ( a ) 按1 .所述的同一频率，对一个量程的五个电压电平进行线性测试。
2.
Measurement at one frequency for selected levels ( normally at 20 db step ) ; and 按一频率，测量几个选定电压电平值，通常电压电平值的间距为20db 。
3.
Frequency accuracy check at 6 different frequency settings at one voltage level ( normally at 1 v ) 一个电压电平(一般为1v )六个不同频率的频率准确度检查。
4.
Instrument transformers - three - phase voltage transformers for voltage levels having u up to 52 kv ; german version hd 587 s1 : 1993 仪表用变压器.电压电平um52kv以下用三相电压变压器
5.
Measurement at one voltage level ( normally 1 v ) for a specified number of different frequencies . the number of frequencies tested will determine the calibration fee 按指定数目，测量于不同频率的电压电平值(一般为1v ) ，校正收费视乎频率的数目而定。
