User's Manual

3.2 Time base of the RF frequency
-SIGFOX
For Sigfox RF frequency, a TCXO(50MHz) is a clock reference.
-BLE
Using external 32.768 kHz crystal for RTC.
The 64 MHz crystal oscillator (HFXO) is controlled by a 32 MHz external crystal.
-WIFI
The high frequency clock on ESP8285 is used to drive both transmit and receive mixers.
This clock is generated from internal crystal oscillator and external crystal. The crystal frequency is 26 MHz.
-GPS(GLONASS)
The RTC is driven internally by a 32.768 Hz oscillator, which makes use of an external RTC crystal.
For GPS(GLONASS) RF frequency, a TCXO(26MHz) is a clock reference.
3.3 Transmission
-SIGFOX
The Tx path produces a DBPSK-modulated signal. Modulate RF signal generated by the synthesizer. The
modulated RF signal is fed to the integrated RX/TX switch and antenna interface and then out of the S2-LP.
-BLE
The RADIO contains a 2.4 GHz radio receiver and a 2.4 GHz radio transmitter that is compatible with
Nordic's proprietary 1 Mbps radio modes in addition to 1 Mbps Bluetooth® low energy mode.
-WIFI
The 2.4 GHz transmitter up-converts the quadrature baseband signals to 2.4 GHz, and drives the antenna with
a high-power CMOS power amplifier. The function of digital calibration further improves the linearity of the
power amplifier, enabling a state of art performance of delivering +19.5 dBm average power for 802.11b
ransmission and +16dBm for 802.11n transmission.
Additional calibrations are integrated to offset any imperfections of the radio, such as:
• Carrier leakage
• I/Q phase matching
• Baseband nonlinearities
These built-in calibration functions reduce the product test time and make the test
equipment unnecessary.
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