AN4103

Receiver parameters

Doc ID 023130 Rev 1

13/20

3

Receiver parameters

All the measurements given in the following sections have been measured under these

The product family of short-range radio devices is divided into three receiver categories,

each having a set of relevant receiver requirements and minimum performance criteria. The

set of receiver requirements depends on the choice of the receiver category by the

equipment provider. SPIRIT1 is a transceiver meeting the requirements of receiver category

2. This category is defined as medium reliable SRD communication media that can cause

inconvenience to persons, which cannot simply be overcome by other means.

The main parameters that have to be measured for the category 2 devices are the

sensitivity, the blocking and the receiver spurious radiation. The adjacent channel selectivity,

receiver saturation at adjacent channel and spurious response rejection measurements fall

within the receiver category 1, so SPIRIT1 does not have to meet these requirements.

3.1

Receiver sensitivity

The receiver sensitivity is the minimum level of the signal at the receiver input, produced by

a carrier at the nominal frequency of the receiver, modulated with the normal test signal

correction.

Under normal test conditions, the value of the maximum usable sensitivity for 25 kHz

channel spacing equipment with a 16 kHz bandwidth shall not exceed -107 dBm. If the RX

bandwidth is not 16 kHz, the sensitivity limit is modified according to the following formula:

Equation 1

The measurement is performed using an RF signal source generator centered at the same

receiver frequency as the desired modulation signal. The demodulated data and clock are

taken from the SPIRIT1 receiver and sent to the same generator to do the BER

measurement. The generator signal level is reduced until a BER of 1% is obtained.

To reduce the power consumption an internal SMPS is integrated in SPIRIT1. Figure 13

demonstrates the ETSI 1% BER sensitivity limit (red line) and the SPIRIT1 sensitivity for

different data rates with internal and external SMPS. This application note outlines the

expected performance when using SPIRIT1 under EN 300 220-1 (v2.3.1, 2012-02) [2] in the

169.400 - 169.475 MHz band, with the maximum channel spacing

the real performance of the SPIRIT1 transceiver, a data rate great than 50 kbps is shown.

The SPIRIT1 is fully compliant with the ETSI class 2 receiver sensitivity requirements by a

large margin.