The parameter settings of the receiving components of an ultrasonic pulse generator receiver directly affect signal quality, measurement accuracy and system stability. These settings should be adjusted according to the probe characteristics, material properties and detection targets. The following is the setting method, basis and typical scene analysis of the core parameters:

Core Parameters of the Pulser Receiver

Gain

Function Amplifies weak echo signals to improve the signal-to-noise ratio (SNR) and ensure that subsequent circuits or oscilloscopes can detect the signal.

Setting reference:

Probe Sensitivity: Low sensitivity probes (e.g., high frequency or narrow band probes) require high gain (e.g., 40-60 dB). Higher sensitivity probes (e.g. low frequency bicrystal probes) can be set to 20-30 dB.

Material Attenuation: High attenuation materials (e.g. cast iron, composites) require increased gain to compensate for energy loss. Low attenuation materials (e.g. steel, aluminum) can reduce the gain.

Signal Amplitude Requirements: The return signal should be 60%-80% of the vertical range of the oscilloscope (e.g., 1-1.6 V peak-to-peak at 1 V/div) to avoid saturation or noise interference.

Typical range: 0-60 dB (adjusted in 1 dB steps). Example: Model PR20 has a gain range of 0-60 dB.

Bandwidth

Function:Limits the frequency range of the received signal, affecting the resolution and noise level.

Setting reference:

Probe Bandwidth: Matches the -3 dB bandwidth of the probe (e.g., set 2-10 MHz for a probe labeled 2-10 MHz).

Probe Target: Use a wide bandwidth for thin materials (high resolution) and a narrow bandwidth for thick or highly attenuated materials (noise reduction).

Damping

Function:Adjusts the impedance matching of the receiving circuit to suppress probe ringing and improve resolution.

Setting Reference:

Probe Impedance: Matches the nominal impedance of the probe (usually 50Ω or 100Ω).

Waveform Observation: Increase damping (e.g. from 50Ω to 90Ω) if echo ringing exceeds 2 cycles. If the signal amplitude is low, decrease the damping.

Typical values: 50Ω, 90Ω or high impedance. For example, PR20 supports 34Ω, 50Ω, 90Ω and 510Ω options.

Trigger

Function:Synchronizes transmission and reception for a stable signal.

Setting Reference:

Trigger source: Internal trigger (for single-channel self-test) or external trigger (for multi-device synchronization, e.g. oscilloscope external trigger).

Trigger Level: Set to 1.5-2 times the amplitude of the noise to avoid false triggering (e.g. 0.2 V peak-to-peak noise with a trigger level of 0.3 V).

Typical parameters: edge trigger (rising/falling edge), pulse width trigger, adjustable trigger level (±5 V).

PR Series General Setting Process

Initialization Parameters: Set the center frequency and nominal impedance according to the probe label (e.g., 5 MHz bi-crystal probe, 50Ω damping).

Coarse Gain Adjustment: Gradually increase the gain from the lowest gain until the return amplitude reaches 60% of the full scale of the oscilloscope (e.g., 1.2 V peak-to-peak at 1 V/div).

Optimize Damping: If the waveform rings for more than 2 cycles, adjust the damping (e.g., increase from 50 Ω to 100 Ω).

Verify Stability: Ensure echo amplitude fluctuations are less than 5% for multiple acquisitions.