ON TOUR XTB (serv.man12) - JBL Audio EMC - CB Certificate (repair manual). Page 11

 

 

 

 

 

 

4.2. 

Configuration and Methods of Measurements for Radiated Emissions 

 

ETSI 300 220 also specifies limits and methodology for radiated emissions testing.  Initially, the primary 

emission frequencies are identified inside a shielded chamber by positioning a broadband receive antenna one 

meter from the EUT.  Next, the EUT and associated system are placed on a turntable on a ten-meter or three-

meter open area test site (OATS) with known attenuation characteristics and all significant radiated emissions 

are recorded.  To ensure that the maximum emission at each discrete frequency of interest is observed, the 

receive antenna is varied in height from one to four meters and rotated to produce horizontal and vertical 

polarities, and the turntable is also rotated to determine the worst emitting configuration. The numerical results 

of the test are included herein to demonstrate compliance. The numerical results of the test are included 

herein to demonstrate compliance.   

 

The numerical results that are applied to the emissions limits are arrived as demonstrated by the example 

below: 
 
 
 
 
 
 
 
A.   Frequency Measured in MHz. 
B.   Meter Reading: Emission Amplitude as measured with the antenna in Vertical polarity in dBμV, this is from the EMI 

receiver or Spectrum Analyzer. 

C.   Meter Reading: Emission Amplitude as measured with the antenna in Horizontal polarity in dB

μV, this is 

from the EMI receiver or Spectrum Analyzer. 

D.   Detector used: Q for Quasi-Peak, A for average, P for peak. 
E.   EUT Side F/L/R/B: Side of EUT facing the receiving antenna. Front, Left, Right, Back. If not noted, 

emission did not peak in a significant manner to discriminate which side of the EUT emitted the emission. 

F.   Ant. Height m: Antenna height in meters of strongest emission when the antenna was raised from 1 to 4 

meters, vertical or horizontal. 

G.  Max Reading: Max meter reading of B vertical and C horizontal in dB

μV. 

H.   Corrected Reading: Corrected Reading in dB

μV/m; Max Reading corrected for cable loss (dB), antenna 

factor (dBV/m) and preamplifier gain (dB). 

I. 

Spec limit: Specification Limit at the measured frequency in dB

μV/m. 

J.   CR/SL Diff.: Difference in dB of Corrected Reading and Specification Limit, negative result is pass margin. 
K.   Pass Fail: Result; EUT does or does not comply at this frequency. 
 
Example: 
44.6 dB

μV (Meter reading—Max.) 

+0.8 dB (cable loss @ frequency) 
45.4 dB

μV 

+11.5 dB/m (antenna factor @ frequency) 
56.9 dB

μV/m  

-32.7 dB (preamplifier gain @ frequency) 
24.2 dB

μV/m --Final Corrected Reading 

30.0 dB

μV/m Specification Limit @ frequency 

-5.8 dB CR/SL Difference. 
Pass as difference is negative (below limit).

A

B

C

D

E

F

G

H

I

J

K

Meas.

Meter

Meter

Det.

EUT

Ant.

Max.

Corrected

Spec.

CR/SL

Pass

Freq.

Reading

Reading

Side

Height

Reading

Reading

limit

Diff.

Fail

(MHz)

F/L/R/B

m

(dB

μV)

(dB

μV/m) (dBμV/m)

(dB)

47.2

44.5

44.6

Q

-

1.0

44.6

24.2

30.0

-5.8

Pass