SWRA370A September   2011  – December 2025 CC1100 , CC1101 , CC2500 , CC2510 , CC2520 , CC2530 , CC2530-RF4CE , CC2540 , CC2540T , CC2541 , CC2541-Q1

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
    1. 1.1 Acronyms
  5. 2Standards and System Requirements
    1. 2.1 Standards
    2. 2.2 Test Equipment Suppliers
    3. 2.3 Radio Certification URLs
  6. 3Test Equipment Requirements
    1. 3.1 System Setup
      1. 3.1.1 Conducted Test Systems
      2. 3.1.2 Radiated Test Systems
    2. 3.2 Initial Considerations for Testing
    3. 3.3 Testing Reminders
  7. 4Software Setup
    1. 4.1 SmartRF Studio 7
      1. 4.1.1 SmartRF Studio 7 Start-Up Window
      2. 4.1.2 SmartRF Studio 7 Modes
      3. 4.1.3 SmartRF Studio 7 Device Control Panel
      4. 4.1.4 SmartRF Studio 7 Software User Manual
    2. 4.2 SmartRF Studio 8
      1. 4.2.1 SmartRF Studio 8 Start-Up Window
      2. 4.2.2 SmartRF Studio 8 Radio Control Window
      3. 4.2.3 SmartRF Studio 8 Software User Guide
  8. 5DUT and Test Instrument Information
    1. 5.1 DUT
    2. 5.2 Test Instruments
  9. 6Clock Frequency Tuning
    1. 6.1 HF Clock Tuning Utilizing the Internal Cap Array
    2. 6.2 LF Clock Tuning
  10. 7Transmission Tests
    1. 7.1 Transmission Power
    2. 7.2 Power Spectral Density Mask
    3. 7.3 Error Vector Magnitude
    4. 7.4 Transmission Center Frequency Offset
    5. 7.5 Spurious Emissions
  11. 8Receive Testing
    1. 8.1 Receiver Sensitivity
    2. 8.2 Interference Testing
    3. 8.3 Interference Testing with RF Generator
  12.   Appendix A Offset EVM vs. EVM
  13.   B References
  14.   B Revision History

Appendix A Offset EVM vs. EVM

Offset EVM and EVM are both measurements of error vector magnitude; in other words, how far from the ideal position the actual signal position is.

The difference between offset EVM and EVM is when to obtain these measurements. In offset EVM measurements, calculate the EVM for the in-phase (I) portion of the signal at the start of the symbol, and the quadrature-phase (Q) portion at the middle of the symbol. Using this approach, users can obtain the EVM at the actual decision points that the demodulator makes when trying to decode it. This method is the correct way to measure EVM because it reflects the actual demodulator in the CCxxxx devices.

For a perfect signal, it does not matter if you use offset EVM or EVM. For spectrums where the I and Q phases are more noisy in the respective transitions than at the decision points, performing a regular EVM measurement gives you a poorer result, but does not affect the ability to receive the signal.