Hi, The test level specified in EN55024 is 3 V/m unmodulated, rms (Erms). You calibrate the forward power in order to get 3 V/m rms unmodulated. At this point the peak value of the unmodulated sinusoidal field is Epk = Erms = 3 V/m. When you test, you apply 80% AM to this wave. At this point is the rms value still 3 V/m ? (yes according to Ed's answer). The peak values are changed: AM Epk = (1+0.8) x Epk = 1.8 Epk = 7.6 V/m. Where Epk is the peak value of unmodulated carrier (= sqrt(2) x Erms = 4.24 V/m). AM Epk-pk (peak-to-peak value of 80% AM field) = 2 x sqrt(2) x 1.8 x Erms = 5.09 x Erms = 15 V/m. The rms value (3 V/m) is most significant, but the peak value changes a lot !
my 2 cents.... Paolo Roncone Compuprint s.p.a. Italy -----Messaggio originale----- Da: Gary McInturff [SMTP:[email protected]] Inviato: mercoledì 6 settembre 2000 23.47 A: 'Bronaugh, Edwin '; ''[email protected]' ' Oggetto: RE: Immunity Testing to EN55024 Are you sure you are reading that correctly. In the radiated portion in a note to the side of the levels it says that the test level is prior to modulation. I believe that is trying to say turn up the levels until 3 v/m measured and once that is done then begin the modulation and start sweeping through the test frequencies. gary -----Original Message----- From: Bronaugh, Edwin To: '[email protected]' Sent: 9/6/00 11:31 AM Subject: RE: Immunity Testing to EN55024 It remains 3 V/m. However, the peak envelop power is 5.1 dB higher than the unmodulated carrier level. If you set a signal generator to produce an unmodulated carrier (usually through an amplifier) of 3 V/m and then modulate it 80 %, the generator will still show the same carrier level, but the amplifier will have to produce nearly four times as much power. If you measure the E-Field level with an average (carrier) detector in an EMI meter, the carrier level will not change from unmodulated to modulated. If you use a peak detector, the E-Field level will be 5.1 dB higher. EdB -----Original Message----- From: Antonio Cinquino [mailto:[email protected]] Sent: Wednesday, September 06, 2000 10:34 AM To: '[email protected]' Subject: Immunity Testing to EN55024 Hello Group, Table 1 of EN55024 calls for a test specification of 3 V/m (umodulated, r.m.s) radio-frequecny EM field for Immunity at the enclosure port. Does anyone know off-hand the value when the signal is 80% modulated with an AM signal of 1kHz as called for in the same table? Antonio Cinquino CAE Electronics Ltd. Electrical System Designer Phone : (514) 341-2000 (ext. 4303) Fax : (514) 340-5552 Email : [email protected] <mailto:[email protected]> ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: [email protected] Michael Garretson: [email protected] For policy questions, send mail to: Richard Nute: [email protected] ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: [email protected] Michael Garretson: [email protected] For policy questions, send mail to: Richard Nute: [email protected] ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: [email protected] Michael Garretson: [email protected] For policy questions, send mail to: Richard Nute: [email protected] ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: [email protected] Michael Garretson: [email protected] For policy questions, send mail to: Richard Nute: [email protected]
