Multichannel ultrasonic data asquisition subsystem for NDT
Ultrasonic inspection is a method of acoustic non-destructive testing (NDT). NDT systems utilizing multi-element ultrasonic sensors, known as ultrasonic phased arrays, have become widely adopted. These systems enable ultrasound inspections at higher speeds compared to single-element sensor devices but require a high-performance data collection subsystem. The proposed subsystem captures and processes all signals from multi-element sensors in real time.
The subsystem is composed of independent channels and is designed using a modular architecture.
Features
Emitter
Number of transmitters: up to 128.
Probing pulse voltage: -50 to -180 Volts per 50 ohm load.
Probing pulse shape: rectangular, negative.
Probe pulse width: from 12.5 ns to 800 ns, adjustable in 2 ns increments.
Front duration: 9 ns +/- 3 ns (amplitude increase from 10% to 90%).
Drop duration: 20 ns +/- 5 ns (amplitude decay from 90% to 10%).
Output impedance: 50 ohms.
Pulse repetition rate: up to 15 kHz, depending on the pulse width, probing voltage, sampling frequency, and monitoring range.
Probing pulse delay: from 0 ns to 12.8 microseconds in 0.25 ns increments.
Receiver
Number of receivers: 128 (16 MUX 8).
Input impedance: 50 ohms, other values are implemented if necessary.
Threshold value of input voltage: 100 uV.
Max. input voltage value: 10 VSS.
Dynamic range of the amplifying path: 0-100 dB, in 0.1 dB increments.
Type of amplifying path: linear.
HRF (Temporary sensitivity adjustment):
Dynamic range: 0-80 dB with a 0.1 dB installation step, 256 reference points.
Minimum distance between the reference points: 1 microsecond. The dynamic range of the RF is reduced by the value of the base gain.
Steepness of the HRF: up to 40 dB/ms.
Frequency range of the amplifying path: from 500 kHz to 20 MHz (level -3 dB).
Analog filters: 2 bandpass filters at selected frequencies.
Operating modes: Echo-pulse, separate-combined.
Signal delay in the channel: precise setting from 3.2 ns to 14.8 ns in 10 ps increments; rough installation from 12.5 ns to 819 microseconds with a step of 12.5 ns.
Any ultrasonic sensor element can function as both an emitter and a receiver.
Digital Block
ADC: 16 bit (15 bit + sign bit), 200 MHz.
ADC dynamic range: >72 dB at 80 MHz digitization frequency.
Sampling frequency: 80, 40, 20, 10 MHz, adjustable for the measurement cycle.
Temporary resolution: 12.5, 25, 50, 100 ns depending on the digitization frequency.
TCP/IP interface for the exchange of control information between system blocks.