Calculating Phase Noise Margins for Industrial Wi-Fi Seven Modules Operating near Arc Welders
Phase noise margin calculations near arc welders demand adding reciprocal mixing degradation figures directly to local oscillator phase noise floors.
Local Oscillator Jitter
Meaning
Timing instability in a periodic reference signal leads to phase variations that affect the performance of a radio frequency system. This local oscillator jitter causes the signal to spread in the frequency domain.
Frequency Purity
Phase noise and timing fluctuations determine the spectral purity of the generated waveform. Low levels of local oscillator jitter are essential for maintaining a high signal to noise ratio in the receiver chain. When the jitter becomes excessive, the ability of the system to distinguish between closely spaced constellation points in a QAM signal is degraded.
Hardware Source
Thermal noise and the quality of the crystal reference are primary factors that contribute to the instability of the clock source. Selection of a high-quality temperature compensated crystal oscillator can measurably reduce local oscillator jitter in outdoor deployments. The design of the phase locked loop also influences how much noise is filtered or amplified within the circuit.
Modulation Accuracy
Excessive jitter in the timing circuit results in increased bit error rates and reduced data throughput. System engineers prioritize low noise floor specifications in the reference clock to maintain the integrity of the data transmission. Advanced digital signal processing can compensate for some timing errors but cannot fully overcome the limits imposed by poor hardware stability.