Page 205 - GuideFWA

2. SPURIOUS AND OUT-OF-BAND EMISSIONS

Report [1], section IV.F.2.2, states:

“The analysis presented before has taken as input the appropriate modulation mask for the
technology in question. It is argued by some that this is not entirely adequate since in general
all the normally specified spectrum components should be included viz. spurious and out - of -
band emissions (together termed unwanted emissions) and also the fast transient components.
On the other hand some have argued that there is no need to include these other components,
and for simplicity the analysis is based on this assumption”.

2.1. LMNQ VIEW

The analysis presented in PCC.III-935/97 has taken as input the appropriate modulation mask for
the technology in question. The modulation mask usually identifies emissions thought essential
for the communication function. However, in reality, any regularly occurring emission will
potentially impact a victim and should be included.

For some technologies, the simple modulation mask may not be entirely adequate since spurious
and out - of - band emissions (together termed unwanted emissions) and also the fast transient
components may be regular and of significant magnitude. For example, the DECT specification,
shows that the transmitter transient emissions may be significantly higher than the normal
modulation emissions with corresponding impact on victim systems and thus the basic
modulation mask is not worst case as suggested by AENS below.

Extract from ETSI document ETS 300 175-2 Sections 5.5.1 &
5.5.2

Emissions on RF Maximum Power Maximum Power
channel “Y” Level from Level from
Transients Modulation

Y=M±1 250 µW 160 µW

Y=M±2 40 µW 1 µW

Y=M±3 4 µW 40 nW

Y = Any other 1 µW 20 nW

DECT channel

The power in RF channel Y is defined by integration over a

bandwidth of 1 MHz centered on the nominal centre frequency ,

Fy. …….

Table 2.1 Permitted DECT Transient and Modulation Power Levels

Inter-American Telecommunication Commission 191