Patent ID: 8030947

Claim:
An electronic apparatus noise measurement method comprising: connecting each of second and third ports of a network analyzer to a connection portion which is configured to be connected to a predetermined measurement point on a circuit to be measured; connecting a cable to the circuit to be measured; connecting an antenna for receiving an electromagnetic wave radiated from the cable to a first port of the network analyzer; measuring a three-port S parameter of the first, second, and third ports using the network analyzer, the three-port S parameter being expressed by an equation (1) when waves that enter the first, second and third ports are respectively represented by a 1 , a 2 and a 3 and waves that are reflected from the first, second and third ports are respectively represented by b 1 , b 2 and b 3 ; [ b 1 b 2 b 3 ] = [ S 11 S 12 S 13 S 21 S 22 S 23 S 31 S 32 S 33 ] ⁡ [ a 1 a 2 a 3 ] ( 1 ) converting the three-port S parameter into a mixed-mode S parameter expressed by equations (2) and (3); and [ b s ⁢ ⁢ 1 b c ⁢ ⁢ 2 b d ⁢ ⁢ 2 ] = [ b 1 1 2 ⁢ ( b 2 + b 3 ) 1 2 ⁢ ( b 2 - b 3 ) ] , [ a s ⁢ ⁢ 1 a c ⁢ ⁢ 2 a d ⁢ ⁢ 2 ] = [ a s ⁢ ⁢ 1 1 2 ⁢ ( a 2 + a 3 ) 1 2 ⁢ ( a 2 - a 3 ) ] ( 2 ) [ b s ⁢ ⁢ 1 b c ⁢ ⁢ 2 b d ⁢ ⁢ 2 ] = [ S ss ⁢ ⁢ 11 S sc ⁢ ⁢ 12 S sd ⁢ ⁢ 12 S cs ⁢ ⁢ 21 S cc ⁢ ⁢ 22 S cd ⁢ ⁢ 22 S ds ⁢ ⁢ 21 S dc ⁢ ⁢ 22 S dd ⁢ ⁢ 22 ] ⁡ [ a s ⁢ ⁢ 1 a c ⁢ ⁢ 2 a d2 ] ( 3 ) calculating common-mode and normal-mode components of the electromagnetic wave radiated from the cable by calculating a common-mode component of S sc12 of the equation (3) by (S 12 +S 13 )/√2 and calculating a normal mode component of S sd12 by (S 12 −S 13 )/√2.