TH7122 Datasheet, PDF (16/44 Pages) Melexis Microelectronic Systems – 27 to 930MHz FSK/FM/ASK Transceiver

TH7122
27 to 930MHz
FSK/FM/ASK Transceiver
3.3.2 Output Power Adjustment
20.00
The maximum output power is adjustable via
the external resistor RPS as shown in Figure
8. There are four predefined power settings ^10.00
in programmable user mode which can be
set in the register TXPOWER. The maxi-
0.00
mum power setting P4 is the default setting.
-10.00
-20.00
Fig. 8: Output power vs. RPS
-30.00
-40.00
1
P4
315MHz
433MHz
868MHz
915MHz
10
100
RPS / kOhm
3.3.3 Modulation Schemes
The RF carrier generated by the PLL frequency synthesizer can be ASK or FSK modulated. Depending on
the selected user mode, the modulation type can be selected either by the ASK/FSK pin or via the serial
control interface. Data is applied to pin IN_DTA. The data signal can be inverted by the bit DTAPOL. The
following tables for ASK and FSK modulation are valid for non-inverted data (DTAPOL = 0)
3.3.4 ASK Modulation
IN_DTA
0
1
Description
Power amplifier is turned off
Power amplifier is turned on
(according to the selected output power)
The transceiver is ASK-modulated by
turning on and off the power amplifier.
Please also refer to para. 1.3 for ASK
modulation limits.
39010 07122
Rev. 008
Page 16 of 44
Data Sheet
June/07