TDA5250D2_07 Datasheet, PDF (77/94 Pages) Infineon Technologies AG – ASK/FSK 868MHz Wireless Transceiver

Figure 3-39 Datarates and Sensitivity
TDA5250 D2
Version 1.7
Application
BER_Datarate.wmf
3.10.5 Sensitivity at Frequency Offset
Applying the test setup in Figure 3-36 even a wide offset in the received frequency spectrum results
only in a slight decrease of receiving sensitivity. At an offset of 100kHz one of the two 50kHz FSK
peaks is at the 3dB border of the IQ filter (150kHz), which is the reason for the decline of the
sensitivity (see point A in Figure 3-40).
A frequency offset of 50kHz (FSK deviation: 50kHz) increases the data jitter of the demodulated
signal and therefore results in little loss of sensitivity (see point B in Figure 3-40).
In this case one of the peaks of the FSK-spectrum lies in the DC-blocking notch of the baseband
limiters.
Figure 3-40 BER Frequency Offset
BER_FrequOffset_FSK_3V..wmf
Data Sheet
77
2007-02-26