AN873 Si446X AND FCC PART 15.247 DIGITAL TRANSMISSION SYSTEM COMPLIANCE AT 902-928 MHZ
This application note demonstrates the compliance of Si446x RFICs with the regulatory requirements of FCC Part 15.247 for Digital Transmission Systems (DTS) operating in the unlicensed 902-928 MHz band. Within this frequency band, the FCC allows a transmit power level of up to 1 watt if certain operational conditions are met.The primary intent of these restrictions is to minimize interference to other operators in the band through“spreading” of the signal energy. This spreading may be accomplished in both the frequency and time domains through use of a Frequency Hopping Spread Spectrum (FHSS) system, or only in the frequency domain through use of a Wide band Digital Transmission System. In a DTS device, the signal energy may be spread across a wide bandwidth by use of digital modulation with a combination of a high data rate and/or high frequency deviation. As a result, a high level of transmit power level may be used while maintaining a relatively low power spectral density(PSD) at any point in the modulation spectrum.
The FCC previously required a DTS device to spread the signal energy through a modulation technique known as Direct Sequence Spread Spectrum (DSSS). In a DSSS system, the binary data of the transmit data stream is multiplied with a higher-rate pseudo-random chip sequence. The resulting data stream takes on the rate of the chips equence and thus the bandwidth of the modulated signal on the air interface increases accordingly. The reverse process is performed on the receive side of the link; the received signal is again multiplied with a local copy of the pseudo-random chip sequence to “collapse” the signal down to its original bandwidth.
The FCC has recently eliminated the requirement that DTS devices must use DSSS techniques and now allows any form of wideband digital modulation to be used, as long as the resulting 6 dB bandwidth is above a minimum value (500 kHz) and the PSD is below a maximum level (+8 dBm / 3 kHz). Part 15.247 does not require use of a specific type of modulation (e.g., OOK, FSK, BPSK, QPSK, QAM, etc.)
This application note is concerned only with DTS devices, and does not discuss or demonstrate operation as a FHSS device. As will be shown, compliance is readily obtained when the high-power members of the Si446x family(e.g., Si4463/Si4464) are configured for their maximum transmit power level of +20 dBm. As a result, any of the chips within the Si446x family (including lower-power members such as Si4460 and Si4461) may also be used to achieve compliance. The measurements presented within this document were taken with a Si4463-B1 RFIC mounted on a 4463-PCE20C915-EK RFSW Pico RF Test Card (see section "5. Reference Design Schematic" on page 28).
The Si4463 chip was configured to transmit at its maximum power level by setting the PA_PWR_LVL property =0x7F. Various data rates and deviations were chosen in order to comply with the required minimum 6 dB bandwidth and required maximum power spectral density. The tests were performed at room temperature with a supply voltage of VDD=3.3 V.
|
|
|
|
Application note & Design Guide |
|
|
|
|
Please see the document for details |
|
|
|
|
|
|
|
|
|
|
|
English Chinese Chinese and English Japanese |
|
|
2017/07/27 |
|
|
Rev. 0.2 |
|
|
AN873 |
|
|
6.1 MB |
- +1 Like
- Add to Favorites
Recommend
- Silicon Labs Simplifies IoT Development with Simplicity Studio 5
- Silicon Labs Strengthens Isolated Gate Driver Portfolio
- Software Speeds Development of IEEE 1588 System Integration | Silicon Labs
- Silicon Labs Expands Isolated Gate Driver Product Family Ideal for Hybrid and Electric Vehicles (EV)
- News | Silicon Labs and Amazon Collaborate on Sidewalk, a New Shared Network for IoT Consumer Devices
- IoT Hero Aclara Empowers Utility Companies to Detect Water Leaks and Conserve Usage with Silicon Labs‘ Transceivers
- Silicon Labs and Skyworks reach agreement to sell infrastructure and automotive business
- Silicon Labs Z-Wave Wireless Selected for Johnson Controls Next Generation Qolsys Smart Home Panel
All reproduced articles on this site are for the purpose of conveying more information and clearly indicate the source. If media or individuals who do not want to be reproduced can contact us, which will be deleted.
Integrated Circuits
Discrete Components
Connectors & Structural Components
Assembly UnitModules & Accessories
Power Supplies & Power Modules
Electronic Materials
Instrumentation & Test Kit
Electrical Tools & Materials
Mechatronics
Processing & Customization
