SRRC Filing Timelines for a Product Entering China
SRRC radio type approval in China takes 8 to 16 weeks, requiring local agent representation, strict customs sample clearing, and accredited domestic lab scans.
Frequency Tolerance Measurement
Meaning
Evaluation of carrier accuracy assesses how far a radio signal drifts from its assigned central position under different operating conditions. Performing a frequency tolerance measurement verifies that the device remains within its allotted channel to prevent crosstalk with neighboring users. This value is expressed in parts per million or hertz and must stay within strict limits set by international telecommunications groups.
It confirms that the master oscillator maintains its focus despite voltage fluctuations or mechanical vibrations.
Carrier Stability
Measurements take place across a range of supply voltages to simulate a battery moving from full charge to exhaustion. Frequency tolerance measurement requires a signal analyzer that is significantly more accurate than the radio unit under test. If the signal drifts by more than twenty parts per million, it could slip into adjacent bands and cause interference.
High-performance oscillators are chosen to keep this margin as low as possible during operation.
Thermal Influence
Extreme heat or cold often causes the physical crystals in the radio path to vibrate at incorrect rates. During frequency tolerance measurement, the device is placed in a thermal chamber and cycled between negative thirty and positive fifty degrees Celsius. Observations at every five-degree increment reveal the temperature profile of the internal crystal.
Any device that moves outside its designated mask at these extremes fails the qualification.
Temporal Stability
The observation period ensures that the long-term frequency drift does not violate spectral masks over months of continuous use. Frequency tolerance measurement helps identify manufacturing defects in the timing components early in the board production cycle. Verification against host settings confirms the software can compensate for small amounts of natural aging in the hardware.
Final entries in the database specify the maximum drift observed across all test conditions.