ST STM32WL5 Series User Manual

RM0453 Rev 1 165/1461
RM0453 Sub-GHz radio (SUBGHZ)
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index. An optional Gaussian filter can be used. All modulation parameters are set using
Set_ModulationParams() command.
The bit rate (or equivalent chip) is referenced to the HSE32 frequency and controlled by the
BR parameter, defined as follows:
BR = 32 x HSE32
FREQ
/ BitRate where HSE32
FREQ
= 32 MHz
FSK modulation is performed inside the RF-PLL bandwidth, by changing the fractional
divider. The high resolution of the RF-PLL allows very narrow frequency deviation. The
frequency deviation parameter Fdev, is one of the parameters in
Set_ModulationParams(). Fdev is defined as follows:
Fdev= Fdev[Hz] / FreqStep where FreqStep = HSE32
FREQ
/ 2
25
To ensure correct modulation, the following limit applies: (Fdev + BR/2) < BW.
The bandwidth must be chosen so that:
BW[DSB] >
BR + 2 x frequency deviation + frequency error
where frequency error = 2 x HSE32
FREQ
error
The FSK modem offers several pulse shape options in the PulseShape parameter.
The FSK modem with a bit rate above 1.2 kbps and a frequency deviation equal to a quarter
of the bit rate, allows the MSK modulation to be used in both receive and transmit. The
received signal is demodulated like FSK in the frequency domain non coherent.
5.5.4 MSK modem
The MSK modem provides a 2-MSK modulation over a range of data rates from 0.1 Kbit/s
up to 10 Kbit/s. This MSK modulation is only available in transmit mode. The modulation
index is automatically adjusted to 0.5. An optional Gaussian filter can be used. All
modulation parameters are set using Set_ModulationParams() command.
The bit rate (or equivalent chip) is referenced to the HSE32 frequency and controlled by the
BR parameter, defined as follows:
BR = HSE32
FREQ
/ BitRate where HSE32
FREQ
= 32 MHz
5.5.5 Generic framing
The generic packet framing is used with the FSK and MSK modems.
The generic packet provides a conventional packet format for applications in proprietary
NRZ coded, long range, low-energy communication links. The generic packet framing can
be configured by Set_PacketParams() command and allows whitening based on pseudo
random number generation, CRC operations and packet acknowledgment.
The following types of generic packet formats are available:
• Variable length packet: including a short header that contains information about the
number of payload bytes
• Fixed length packet: no header

ST STM32WL5 Series Specifications

General

Brand	ST
Model	STM32WL5 Series
Category	Microcontrollers
Language	English