关于传导杂散在idle mode的理解

关于传导杂散在空闲模式有个特殊的说明，如下
12.1.2.4.2 Procedure
a) Measurements are made in the frequency range 100 kHz to 12,75 GHz. Spurious emissions are measured as the
power level of any discrete signal, higher than the requirement in table 12.4 minus 6 dB, delivered into a 50 Ω
load.
我不清楚这个6db为啥要被减去?
我看0505上没有明确说这个6db啊?
Table 12.4
Frequency range Power level in dBm
GSM 400,
T-GSM 810
GSM 900,
DCS 1 800
GSM 700,
GSM 850,
PCS 1 900
9 kHz to 880 MHz -57 -57
880 MHz to 915 MHz -59 -57
915 MHz to 1000 MHz -57 -57
1 GHz to 1 710 MHz -47
1 710 MHz to 1 785 MHz -53
1 785 MHz to 12,75 GHz -47
1 GHz to 1 850 MHz -47
1 850 MHz to 1 910 MHz -53
1 910 MHz to 12,75 GHz -47

应该是留足够余量的意思。等高手详解

那个 table 12.4是发射杂散的指标吧，idle下指标更高些，毕竟这个时候手机并不处于active状态

同意这个说法

减去6dBm似乎是为了 更好的区分环境噪声和干扰源