This article focuses on the development and analysis of an
Ultrasonic Pulse Velocity (UPV) measurement system used for the
evaluation of concrete and Reinforced Cement Concrete (RCC) in civil
construction. The UPV tester is essential for on-site assessments of
structures, as it is used to measure the velocity of ultrasonic
waves within the material, directly correlating with its
strength. UPV testing is affected by the attenuation of ultrasonic
waves in concrete, particularly due to the interfacial transition
zone. Excess ultrasonic attenuation results in the reduction in the
received signal amplitude which may also results in the omission of
the initial pulses due to threshold comparison at the receiver. The
study highlights the impact of receiver gain on threshold error and
discusses the limitations associated with ADC sampling rate and
amplitude resolution. UPV measurement, including counter or data
acquisition approach, have error contributions associated with
threshold voltage comparison. The error due to threshold amplitude
selection is quantified, emphasizing the importance of accurate
signal analysis, particularly in highly attenuating medium. The
article presents the design and development of a PC-based UPV tester
with automatic threshold error compensation. The system includes a
transmitter, receiver, 32-bit microcontroller, and a Graphical User
Interface (GUI) for data analysis. The article introduces a
two-point linear detection logic to minimize errors caused by
selected signal amplitude and omission of initial pulses in transit
time measurements. The proposed method provides effective resolution
of 10 ns through software, even at low sampling rate of
2 MS/s. The experimental results demonstrate the effectiveness of
the developed UPV tester, with comparisons to a reference
calibration facility at CSIR-NPL. The standard deviation in the
ultrasonic transit time measurement by the developed UPV device,
with threshold error correction, was ±70 ns.