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6.5.4
IF Frequency
TC32306FTG has the single conversion system. The output of LNA is downconverted to IF frequency
by Image Cancel Mixer. Set IF frequency with adequate IF filter bandwidth by setting of register.
Table 6-17 IF Frequency and Internal IF Filter Bandwidth
h'0E[D5] IFBW
6.5.5
Demodulation
Select a type of demodulation (ASK or FSK) by the value of register:h'0A[D4]. Depending upon a type
of demodulation, IF filter output signal has different path, RF detection and additional functions.
h'0A[D5]RX_TX
6.5.6
FSK Demodulation
To select FSK, set register:h'0A[D4] to "0"(FSK).
(1)
NIR (Near Interference Rejection) Filter
Select the filter Enable/Disable by the value of register:h'10[D1]. This filter reduces a interfere signal
near 300 kHz offset frequency. This filter is a notch type and the peak attenuation is about 20 dB. The
notch frequency is selectable by the value of register:h'1B[D2:D1].
A_VDD_3V
RF_OUT
Matching
Network
RF_IN
Matching
Network
RF_DEC
+
Fig 6-10 Typical LNA Network
IF Frequency
0
230kHz
1
280kHz
Table 6-18 Demodulations
h'0A[D4]FSK_ASK
0
0
0
1
1
XX
LNA
Internal IF Filter Bandwidth
(Selected)
320 kHz (typ.)
270 kHz (typ.)
Status
FSK (RX)
ASK (RX)
TX
XX: About TX, see Table 6-30.
22
TC32306FTG
2015-10-01
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