Monitoring the 1 /spl Omega/ standard resistor by quantum Hall effect

Resistance standards at ETL are maintained by quantum Hall effect. Resistance of the 1 /spl Omega/ resistor named 69J101 is monitored. The result is R69J101=1-(5.682/spl plusmn/0.018)/spl times/10/sup -6/+(0.110/spl plusmn/0.003)/spl times/10/sup -6/ t /spl Omega/ where t is time in years from Jan. 1, 1994. The difference of 1 /spl Omega/ standard between ETL and BIPM on 1990 international comparison is reduced from MINUS/0.128 ppm to -0.044 ppm.<>