Rainbow-electronics AT86RF211 User Manual download pdf (Page 13)

AT86RF211

1942C–WIRE–06/02

Figure 13. IF1 Filtering

Figure 14. Schematic Input of IF1 Amplifier

Figure 15. Schematic Output of the Second Mixer

IF2 Filtering and Gain IF2 filtering achieves a narrow channel selection. In case it is not used, it should be

replaced by a > 1 nF coupling capacitor, thus the IF1 filter is the only part achieving the

channel selection. Available commercial filters with a 35 kHz BW allow data rates up to

19.6 kbps if crystal temperature drifts are very low.

For faster communications and/or wider channelization, this ceramic filter can be

replaced by an LC band-pass filter as proposed hereafter.

IF1IN

(pin 35)

330 Ω

IF1

"or"

C > 100 pF

330 Ω

IF1OUT

(pin 36)

Filter

IF1DEC

20 k Ω

330Ω

IF1IN

1600 Ω

IF2OUT

1 2 ... 8 9 10 11 12 13 14 15 16 17 18 ... 47 48

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Rainbow-electronics AT86RF211 User Manual Page 13