Noise measured across silicon single-crystal solar cells may serve as a non-destructive reliability indicator of the devices. The noise sources in monocrystalline solar cells has been described. The noise measuring system and the results of measurement of circular form cells (a diameter of 100 mm and a thickness of 360 µm) have been presented. The DLTS measurements performed on investigated solar cells approved the noise measurement results.

In this paper a Nuclear Magnetic Resonance magnetometer (NMR) in a form of a LabVIEW Virtual instrument (VI) is proposed. The heart of the magnetometer remains the marginal oscillator with a proton sample. The magnetic resonance signal and all other auxiliary signals are generated and controlled by a set-up composed of a digital counter (for resonance frequency measuring), a VXI system (for the modulation signal generation and for the sampling of the oscillator output), a programmable DC voltage source (for oscillator frequency control) and a personal computer controlling the measurement. The virtual magnetometer was built and preliminary test measurements were done. The measuring results of the determination of a field-coil coilconstant showed that the virtual NMR magnetometer’s readings were comparable to the classic NMR magnetometer’s within 5·10^-4.

The characteristics of analog-to-digital converters (A/D converters) are established and assessed based on the results of the conversion of a sinusoidal signal. This method of measurement has been selected because it is relatively easy to generate sinusoidal signals with the required good parameters. Among the criteria of the measurement of an actual a-d conversion is the probability density function (PDF) of the quantization error. Unfortunately, the distribution of the PDF of the error of the quantization of a sinusoidal input signal is not rectangular (because sinusoidal signals do not comply with Widrow’s quantization theorem), and moreover the form of the function is highly sensitive to slight offset errors or gain errors appearing in the part of the signal path preceding the A/D converter. The paper discusses sensitivity of the PDF of the quantization error on the variations of the amplitude of the signal and the possibilities of remedying this situation by means of quantization with dither signal.

IEN system for unlike impedance comparison (resistance vs. inductance, or resistance vs. capacitance) is based on an implementation of the three-voltmeter method, which configures both standards in comparison as four terminal-pair, by using automatic electronic compensations to achieve the purpose. Basic relative accuracy of the instrument is between a few parts in 10^-6 for comparison of impedances in the range 10 Ω to 10 kΩ, and at frequencies in the range 100 Hz - 10 kHz.
The same system, without any changes in the instrumentation employed or its wiring, can be effectively used also as a four terminal-pair ratio bridge for comparison of like impedances (resistance vs. resistance, or capacitance vs. capacitance), in the same impedance and frequency range. This capability has been checked by conducting measurements of resistance ratios of four terminal-pair ac resistors, having nominal ratios of 1:1 and 10:1. Results show that, for like impedances, relative accuracies at the level of a few 10^-7 can be within reach.

It is noticed in the paper that scaling of digital measurement signals and their registration in format which is comfortable to investigations during computer processing increase their volume. Possibility of realization a reverse scaling operation as an initial processing method preceding compression is mentioned.
The authors proposed to complete initial processing by generally well-known operation - calculation of differences between succeeding samples and they tested the additional compression ratio, resulting from the proposed transformations, using experiments.