XE1203F Ver la hoja de datos (PDF) - Semtech Corporation
Número de pieza
componentes Descripción
Fabricante
XE1203F Datasheet PDF : 36 Pages
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XE1203F
The frequency error can then be calculated by using the following formula:
Frequency error = (BR/8)*int(Dataout_FEI(11:0)),
where Dataout_FEI(11:0) = Dataout_MSB_fei(3:0) + Dataout_LSB_fei(7:0), and int(x) is the integer value of the
signed binary representation of x.
4.2 THE TRANSMITTER SECTION
The Transmitter performs the modulation of the carrier by an input bit stream and the transmission of the modulated
signal. Carrier modulation is achieved directly through the frequency synthesizer via a Sigma-Delta modulator. The
frequency deviation and the bit-rate of the modulated carrier are programmable. An on-chip power amplifier then
amplifies the RF signal. The output power can be programmed with 4 possible settings:
RTParam_Tpow
00
01
10
11
Output power
RFOP1
RFOP2
RFOP3
RFOP4
Table 6: Output power settings
4.2.1 Transmitter
The transmit data should be applied to DATA or DATAIN pins depending on the setting of the
ADParam_disable_data_bidir configuration bit. If the parameter is set to “1”, then the DATAIN pin is used, otherwise
the bidirectional pin DATA is used.
The modulating signal on DATA or DATAIN can be pre-processed before modulating the local oscillator to produce
the outgoing FSK RF signal. This is the pre-filtering feature. The pre-filtering is selected by setting the
RTParam_Filter configuration bit to “1”. When RTParam_Filter is set to “1”, the input baseband data is pre-filtered
before being applied to the frequency synthesizer. This means that the rising and falling edge of each bit is linearly
smoothed with a staircase transition. When RTParam_Filter is set to “0”, the input baseband data is applied directly
to the frequency synthesizer without any pre-filtering function.
The two possible modulation methods are shown in Figure 8, where “datain” is the input bit stream from DATA or
DATAIN pins.
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