SWRS046I November 2006 – September 2018 CC1020
PRODUCTION DATA.
The data modulator can modulate FSK, which is a two level FSK (Frequency Shift Keying), or GFSK, which is a Gaussian filtered FSK with BT = 0.5. The purpose of the GFSK is to make a more bandwidth efficient system as shown in Figure 5-17. The modulation and the Gaussian filtering are done internally in the chip. The TX_SHAPING bit in the DEVIATION register enables the GFSK. GFSK is recommended for narrowband operation.
Figure 5-18 and Figure 5-19 show typical eye diagrams for 434 MHz and 868 MHz operation, respectively.
2.4 kBaud, | NRZ, | ±2.025 kHz frequency deviation |
153.6 kBaud, | NRZ, | ±79.2 kHz frequency deviation | ||
2.4 kBaud, | NRZ, | ±2.025 kHz frequency deviation |