Meaning
Dedicated executable code loaded onto a module activates a constant unmodulated radio signal to simplify hardware evaluation and certification. Using continuous wave test firmware allows engineers to observe the carrier frequency at maximum intensity without the fluctuations of normal data traffic. This specialized operating mode prevents the frequency hopping or power management features that complicate standard spectral analysis.
It is standard for laboratories to request this software before initiating a formal radio equipment audit.
Signal Stability
Operating in this mode keeps the transmitter at a fixed frequency to allow for accurate phase noise and stability readings. The continuous wave test firmware bypasses digital modulation, providing a clean peak on the spectrum analyzer. Because there is no data being carried, the signal has an infinitely narrow occupied bandwidth in theory.
The signal stays high-powered for the duration of the measurement to ensure thermal equilibrium in the amplifier.
Diagnostic Mode
Lab technicians use software commands to switch the radio between various channels through the continuous wave test firmware interface. This method reveals the peak current consumption of the device under a worst-case transmit scenario. Testing for peak emission levels helps designers identify resonance issues in the board enclosure.
Switching frequency takes milliseconds, facilitating a rapid sweep across the entire operating band.
Compliance Sequence
Regulatory agencies utilize this firmware to confirm the transmitter stays within the allotted frequency mask when fully loaded. Once continuous wave test firmware provides a passing stability measurement, other tests for harmonic distortion begin. Firmware remains in the device only during the test phase and is removed before the product is shipped to the end user.
If non-authorized parties obtain this firmware, they could force the hardware to transmit indefinitely in a way that violates local law.
