Meaning
Synchronization of an output signal with a reference frequency ensures precise timing for high frequency measurements and data acquisition. In the context of ultrasonic monitoring, a phase locked loop maintains the stability of the excitation frequency sent to the transducers. This precision is necessary for measuring the time of flight of sound waves through a polymer part with nanosecond resolution.
It allows the system to track subtle changes in material density or thickness during the cooling process.
Frequency Synchronization
Synchronization happens through a feedback circuit that compares the phase of the oscillator with the reference signal. If a phase locked loop detects a drift, it adjusts the voltage to the oscillator to bring it back into alignment. This keeps the measurement system from losing accuracy as the electronics warm up.
Signal Stability
Stability of the received signal is improved by ensuring that the sampling window is perfectly timed with the pulse generation. Because the sound velocity in plastic changes rapidly with temperature, a phase locked loop allows the system to lock onto the returning echo even as it shifts in time. This mechanism filters out random noise and interference from the electric motors of the moulding machine.
It provides a clean data stream for the calculation of the final part dimensions.
Timing Accuracy
Accuracy in high speed data acquisition relies on this technology to coordinate several sensors at once. When multiple probes are used to scan a large part, the loop ensures that every reading is taken at exactly the same point in the cycle.
