High frequency (HF) voltage primary standard at NPLI has been realized using a twin resistance coaxial power mount fitted with two tiny resistors which provides proper termination of 50 ohm at the end of coaxial line in the frequency range of 1 MHz to 1000 MHz. The rf/dc transfer difference has been assigned to HF voltage primary standard. This is the key technique for the realization of HF voltage primary standard and its traceability is obtained by assigning effective efficiency, RF impedance and the DC resistance to it against each of the parameters’ reference standard. Measurements are done at the input reference plane of the primary standard. Therefore, measurement uncertainty in assigning the rf/dc transfer difference to the primary standard is the cumulative effect of the uncertainty in determination of effective efficiency, HF impedance and the DC resistance. With the establishment of the HF voltage primary standard, one can calibrate and assign the rf/dc transfer difference to the transfer standard thermal voltage converters.
The rf/dc transfer difference has been assigned to the high frequency thermal voltage converters / transfer standards by comparing it against twin resistive coaxial power mount which is primary standard of HF voltage as shown in the block diagram.