RELATION TO THE LIMIT L FOR CONTINUOUS INTERFERENCE , IS OBTAINED FROM THE FORMULAE : ( SEE O.J . )
THE VALUE OF N SHALL BE DETERMINED AT 160 KHZ , 550 KHZ AND 45 MHZ FOR THE FREQUENCY RANGES 150 TO 500 KHZ , 0 * 5 TO 30 MHZ AND 30 TO 300 MHZ RESPECTIVELY .
3.2.4 . MEASUREMENTS OF RADIO NOISE GENERATED BY SWITCHING OPERATIONS SHALL BE MADE AT THE FOLLOWING RESTRICTED NUMBER OF FREQUENCIES : 160 KHZ , 550 KHZ , 1 * 4 MHZ , 10 MHZ , 45 MHZ , 90 MHZ AND 220 MHZ . A TOLERANCE OF MORE OR LESS 10 % IS PERMITTED FOR THE FIRST FOUR FREQUENCIES , AND MORE OR LESS 5 MHZ ON THE OTHER THREE . FURTHER RESTRICTION TO THE FOLLOWING THREE FREQUENCIES IS PERMITTED FOR PROLONGED TESTS : 160 KHZ , 550 KHZ AND 45 MHZ .
3.2.5 . THE CLICK RATE N SHALL BE DETERMINED UNDER THE OPERATING CONDITIONS SPECIFIED IN SECTION 6 . THE APPLIANCES SHALL THEREFORE BE OPERATED UNDER THESE CONDITIONS FOR THE MEASUREMENT OF DISCONTINUOUS INTERFERENCE .
3.2.6 . FOR CERTAIN APPLIANCES , LISTED IN THE SUBSIDIARY POINTS BELOW , LIMITS AND CONDITIONS LAID DOWN IN 3.2.1 TO 3.2.5 SHALL APPLY WITH THE EXCEPTIONS SPECIFIED .
. MANUALLY OPERATED SWITCHES WHICH ARE INCLUDED IN AN APPLIANCE FOR THE PURPOSE ONLY OF MAINS ISOLATION OR PROGRAMME SELECTION ( E . G . THE SWITCH FOR A LAMP OR AN ELECTRIC TYPEWRITER , BUT NOT STOP-START SWITCHES OF SEWING MACHINES AND CALCULATING MACHINES ) ARE EXEMPTED FROM THE PROVISIONS OF THIS DIRECTIVE .
. FOR APPLIANCES LISTED IN ANNEX 1 , TABLE B AND THE LIKE , THE LIMIT IN THE FREQUENCY RANGE 0 * 15 TO 0 * 2 MHZ SHALL BE : ( SEE O.J . )
IN ADDITION , APPLIANCES LISTED IN ANNEX 1 , TABLE B AND MARKED WITH A DOUBLE ASTERISK , WHICH HAVE INSTANTANEOUS SWITCHING ( I . E . THE DURATION OF EACH CLICK IS LESS THAN 10 MS ) , AND A CLICK RATE OF NOT MORE THAN FIVE SHALL BE DEEMED TO COMPLY WITH THE LIMIT INDEPENDENTLY OF THE AMPLITUDE OF THE CLICKS .
. FOR APPLIANCES WHICH HAVE A CLICK RATE N OF LESS THAN FIVE , ANY TWO DISTURBANCES CAUSED BY THE SEQUENTIAL OPERATION OF TWO OR MORE CONTACTS , EACH DISTURBANCE HAVING A MAXIMUM DURATION OF 200 MS AND NEITHER PRECEEDED NOR FOLLOWED WITHIN TWO SECONDS BY ANY OTHER DISTURBANCE , SHALL BE EVALUATED AS TWO CLICKS EVEN WHEN THE SEPARATION BETWEEN THE DISTURBANCES IS LESS THAN 200 MS .
FOR THIS CLASS OF EQUIPMENT , E . G . REFRIGERATORS , THE EXAMPLE SHOWN IN FIGURE 2C WOULD BE EVALUATED AS TWO CLICKS AND NOT AS CONTINUOUS INTERFERENCE .
. FOR APPLIANCES LISTED IN ANNEX 1 , TABLE D THE CLICK RATE N = FN2/T , WHERE N2 IS THE SUM OF THE SWITCHING OPERATIONS DURING THE