AN3213 Datasheet, PDF (28/64 Pages) STMicroelectronics – ST7570 S-FSK power line networking system-on-chip

ST7570 demonstration board description
AN3213
Simulation of the Tx active filter response against component tolerance, depicted in
Figure 18, shows +/-1 dB variation in gain module within the signal bandwidth, while the Q
variation is more sensitive around 100 kHz.
Figure 18. Montecarlo simulation of the transmission active filter frequency
response
7.1.2
Reception passive filter
The reception filter is made up of the series of a resistor and a parallel L-C resonant. The
transfer function of the filter can be written as:
Equation 5
Where
● R_L is the DC series resistance of the inductor (in this case, about 2 Ω)
● C^‘1 is the parallel of C₁ with the reverse capacitance of the transil diode D₃, which is
about 2 nF.
The center frequency and the quality factor of the filter can be expressed as:
Equation 6
Equation 7
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Doc ID 17429 Rev 1