SWRA696A April   2021  – November 2021 CC1352P , CC1352P7 , CC1352R

 

  1.   Trademarks
  2. 1Introduction
    1. 1.1 Acronyms Used in This Document
  3. 2DSSS Encoding Scheme
    1. 2.1 Convolutional Encoder
    2. 2.2 Direct Sequence Spreader
  4. 3Packet Format
  5. 4Setting Up WB-DSSS in SmartRF Studio
  6. 5Setting Up WB-DSSS in Code Composer Studio
  7. 6Measured Results
    1. 6.1 Receiver Performance
      1. 6.1.1 DSSS = 1, 240 kbps, 2-GFSK, 195 kHz Deviation, 1x Spreading
      2. 6.1.2 WB-DSSS 120 kbps, 2-GFSK, 195 kHz Deviation, 2x Spreading
      3. 6.1.3 WB-DSSS 60 kbps, 2-GFSK, 195 kHz Deviation, 4x Spreading
      4. 6.1.4 WB-DSSS 30 kbps, 2-GFSK, 195 kHz Deviation, 8x Spreading
      5. 6.1.5 WB-DSSS Frequency Offset Tolerance
    2. 6.2 Transmitter Performance and FCC 15.247 Measurements
      1. 6.2.1 WB-DSSS 240 kbps, 2-GFSK, 195 kHz Deviation, 1x Spreading
      2. 6.2.2 WB-DSSS 120 kbps, 2-GFSK, 195 kHz Deviation, 2x Spreading
      3. 6.2.3 WB-DSSS 60kbps, 2-GFSK, 195 kHz Deviation, 4x Spreading
      4. 6.2.4 WB-DSSS 30 kbps, 2-GFSK, 195 kHz Deviation, 8x Spreading
  8. 7References
  9. 8Revision History

6.2 Transmitter Performance and FCC 15.247 Measurements

Table 6-1 gives the FCC 15.247 digital modulation requirements that were tested.

Table 6-1 FCC 15.247 Digital Modulation Requirements [3]
Section Requirements
15.247a2 The 6 dB bandwidth shall be at least 500 kHz
15.247b3 The maximum conducted power shall not exceed 1 W (+30 dBm)
15.247e The power spectral density (PSD) shall not be greater than 8 dBm in any 3 kHz band during any time interval during continuous transmission

Most spectrum analyzers have a measurement option that automatically measures a fixed dB bandwidth. If this is not available, the 6 dB bandwidth must be measured manually by setting up markers.

Measurement setup consisted of the following:

  • Six devices were tested
  • Test results in Table 6-2 are average numbers of six devices
  • SmartRF Studio was used to test the WB-DSSS cases
Table 6-2 FCC 15.247 Digital Modulation Results
DSSS 6 dB BW (15.247 a2) Power (15.247 b) PSD (15.247 d)
1 >500 kHz 19.5 dBm 9.2 dBm
2 >500 kHz 19.5 dBm 9.2 dBm
4 >500 kHz 19.5 dBm 9.5 dBm
8 >500 kHz 19.5 dBm 9.5 dBm
Note: To comply with the 8dBm/3kHz limit, the output TX power must be dropped until the limit is met.

For an explanation of marker lines for 6 dB bandwidth measurements, see Figure 6-19.

GUID-20201216-CA0I-RG5H-GGBN-QFFQ9M7X96WB-low.png Figure 6-19 Explanation of 6 dB Bandwidth Figures