Fixed Frequency Firmware Chip

This topic describes the test items supported by a fixed frequency firmware chip to help you pass the respective certification test. You can go to Tuya Developer Platform > Sample Store and purchase this chip.

The fixed frequency firmware chip is used to test certain radio frequency (RF) items to be certified. In this case, fixed frequency firmware is flashed to the chip. You can weld the chip on a device under test (DUT) or equipment under test (EUT) to create a test sample for the target EMI conduction and radiation certification. An EMI conduction test sample is welded with an RF trace in addition to the fixed frequency firmware chip. The RF trace connects to a device such as a spectrum analyzer through a SubMiniature version A (SMA) connector to run the test. The 3.3V voltage, GND, RX, and TX pins are broken out from the DUT and connected to a computer through a USB to TTL converter. Then, you can run the test software or test commands on the computer to set a fixed frequency for the EUT.

EMI conduction test items

The test items for Conformity of Europe (CE), Federal Communications Commission (FCC), and State Radio Regulation of China (SRRC) are described as examples in the following sections.

CE

• Reference standard: ETSI EN 300 328

• Download: ETSI EN 300 328 V2.2.2.pdf

• Test items:

  Maximum effective isotropic radiated power (EIRP), power spectral density (PSD), duty cycle, Tx-sequence, Tx-gap, and occupied channel bandwidth
  Out-of-band emission, conducted spurious emission, and conducted spurious response

FCC

• Reference standard: Part 15C 15.247

• Download: Part 15C 15.247.pdf

• Test items:

  Conducted maximum output power, 6 dB bandwidth conducted disturbance, PSD, conducted spurs, and sideband emission

SRRC

• Reference standard: Notice Regarding Radio Management Of 2400 MHz, 5100 MHz and 5800 MHz Bands (MIIT No. [2021] 129). The test method of SRRC is in accordance with ETSI EN 300 328.

• Download: MIIT No. [2021] 129

• Test items:
  EIRP, maximum PSD, carrier frequency tolerance, and occupied bandwidth
  Conducted spurious emission and out-of-band emission power

Radiation test items

The test items for CE, FCC, and SRRC are described as examples in the following sections.

CE

Radiated spurious emission and radiated spurious response

FCC

Radiated spurs and radiated sideband

SRRC

Radiated spurs

You can get test software to run the certification test. For more information, see Module Test Tool.