Receiver parameters

AN4305

14/20

DocID024733 Rev 1

Figure 13. Sensitivity vs. data rate with 1% BER

3.2

Blocking

Blocking is a measure of the capability of the receiver to receive a wanted modulated signal

without exceeding a given degradation due to the presence of an unwanted input signal at

any frequency other than those of the spurious responses or the adjacent channels or

bands.

All the blocking results are measured by positioning the input power 3 dB above the

measured sensitivity limit reported in the previous paragraph with a primary signal source

generator. A second generator with an un-modulated signal is used as the interferer and

combined with the primary signal using a power combiner. The second interferer generator

is placed at the desired frequency offset and the power is increased until the BER

degradation of 1% is obtained.

ETSI specifies the blocking limits at two points: ±2 and ±10 MHz. The limit for class 2

receiver at ±2 MHz is 37.7 dB from the 3 dB level above the sensitivity, and at ±10 MHz it is

62.7 dB from the 3 dB level above the sensitivity.

The SPIRIT1 with range extender is fully compliant with ETSI class 2 receiver blocking

requirements, with a large margin.

AM17224v1

-130

-125

-120

-115

-110

-105

-100

-95

1

10

Data Rate [kbps]

Spirit

ETSI Limits