Radio Frequency Testing

As the core component of IoT devices, wireless modules must pass the SRRC certification required by the National Radio Regulatory Commission for sales in the Chinese market. With the full implementation of the Ministry of Industry and Information Technology's standard No. 129 [2021], certification requirements and technical specifications have undergone significant updates. This article will systematically analyze the latest process and technical points of SRRC authentication for wireless modules. 
  
 

1、 Scope of Application and Legal Basis for Certification 
  
According to the Radio Management Regulations of the People's Republic of China, all radio transmission equipment sold or used within China must obtain SRRC certification. This regulation applies to wireless modules that work independently, as well as embedded wireless units integrated into other devices. 
Applicable product types include: -2.4GHz/5.8GHz Wi Fi module - Bluetooth (BLE) communication module - Zigbee, LoRa and other IoT modules - Cellular communication module (4G/5G) 
  

2、 New standard core changes (MIIT [2021] No. 129) 
  
RF parameter requirements upgrade: - Adjustment of Equivalent Omnidirectional Radiated Power (EIRP) limit for 2.4GHz band - Addition of DFS dynamic frequency selection requirements for 5.6GHz band (Band W56) - Stricter modulation bandwidth and frequency tolerance indicators 
Testing method update: - Radiation stray testing adopts new measurement distance specifications - Receiver blocking characteristic testing introduces new interference source scenarios - Conducted disturbance testing at antenna ports introduces new limit curves 
  
3、 Detailed explanation of authentication process 
  
Pre preparation stage: 1 Confirm the operating frequency band and applicable technical standards of the module Prepare technical documents: circuit schematic, RF parameter table, antenna specification sheet 
Sample testing phase: 1 Provide complete functional prototypes and fixed frequency prototypes Complete RF parameter and electromagnetic compatibility tests in authorized laboratories Key testing items: - Frequency range and tolerance - Transmission power and power spectral density - Stray emission level - Receiver sensitivity 
Review and certification stage: 1 Submit test report and technical documentation 2 Radio management agency conducts document review 3 After approval, issue the model approval code (CMIIT ID) 
  
4、 Special requirements for module authentication 
  
Differences between independent modules and embedded modules: - Independent modules require separate application for SRRC certification to obtain an independent CMIIT ID. - Embedded modules can be certified as a whole with the final product, but module technical documentation must be provided 
Key component control: - RF chips need to provide original factory specifications - Antennas need to be labeled with model and gain parameters - Crystal frequency stability needs to meet the requirement of ± 20ppm 
  
5、 Common technical difficulties and solutions 
  
Frequency offset exceeding standard handling: Optimize TCXO circuit design and add automatic frequency calibration function 
Stray emission suppression: adopting shielding cover design and optimizing filter parameters 
DFS test failure countermeasure: Upgrade firmware algorithm to improve channel detection sensitivity 
  
6、 Post certification management requirements 
  
Identification specification: The module body must be clearly labeled with CMIIT ID (format: 2025DPXXXX) 
Change management: Any changes involving RF parameters (chip, antenna, circuit design) must be re certified 
Market supervision: Regulatory authorities conduct regular spot checks, and products that do not comply will face delisting penalties 
  
7、 Suggestions for Enterprise Implementation 
  
Design phase intervention: Import SRRC standard requirements in the early stages of module development 
Test pre evaluation: Conduct pre testing to identify potential issues 
Document management system: Establish comprehensive technical documents and change records 
  
Conclusion 
  
SRRC certification is a necessary passport for wireless modules to enter the Chinese market. The implementation of the new standards has put forward higher requirements for product design, and enterprises need to fully understand the changes in technical specifications and establish a scientific certification management process. 
For the latest standard interpretation and technical support for SRRC certification of wireless modules, please contact Deng Gong-13925591357.