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This paper presents a method for the accurate and traceable measurement of the analog modulation index. A calibrated step attenuator was used as the main apparatus because it has a higher dynamic range and lower uncertainty than a spectrum analyzer or an oscilloscope. In amplitude modulation (AM), the modulation index is obtained from the amplitude difference between the carrier and the first sideband, as in the conventional method. The resolution and calibration uncertainties of the step attenuator were propagated to the measurement uncertainty of the modulation index. The uncertainty produced by the impedance mismatch and repeatability was also included. For frequency modulation (FM) and phase modulation (PM), the modulation index, β, was estimated (with the step attenuator) from the spectrum of each sideband through the nonlinear fitting of the Bessel function. Thus, the uncertainty of the fitting process was added to the uncertainty of the measurement. The three modulations, AM, FM, and PM, exhibited an expanded uncertainty (approximately 95% confidence level, k = 2) of 0.372% for 50% nominal depth of the AM, 88.8 Hz for the peak frequency deviation of 10 kHz, and 0.88 mrad for a 0.1 radian modulation index, respectively.

In this paper, the propagation of uncertainty on a nonlinear measurement model is presented using a higher-order Taylor series. As the derived formula is based on a Taylor series, it is necessary to compute the partial derivatives of the nonlinear measurement model and the correlation among the various products of the input variables. To simplify the approximation of this formula, most previous studies assumed that the input variables follow independent Gaussian distributions. However, in this study, we generate multivariate random variables based on copulas and obtain the covariances among the products of various input variables. By applying the derived formula to various cases regardless of the error distribution, we obtained the results that coincide with those of a Monte-Carlo simulation. To apply high-order Taylor expansion, the nonlinear measurement model should be continuous within the range of the input variables to allow for differentiation, and be an analytic function in order to be represented by a power series. This approach may replace some time-consuming Monte-Carlo simulations by choosing the appropriate order of the Taylor series, and can be used to check the linearity of the uncertainty.

This article presents a standard field generation system with an antenna for the calibration of a Ka-band electric-field probe. We constructed a measurement system having capability of not only rotating the azimuth angle of the probe but also changing the separation distance between the antenna and the probe. As a result, the orientation and separation distance of the probe can be suggested for minimal variation of the measurand, which reduces the overall uncertainty. For traceable electric-field strength measurements, we measured the associated quantities of the power, antenna gain, and impedance of the individual components constituting the field generation system. An evaluation of the uncertainty of the components providing traceability to the system was also conducted. The system is expected to generate a standard field higher than 10 V/m in the frequency range of 26.5–40 GHz. Uncertainty in the correction factors is quantified to determine the factors that affect the calibration, and the expanded uncertainty of the standard field generation system is found to be 5.1% at 26.5 GHz and 5.3% at both 33 and 40 GHz.

To calibrate Ka-band electric field probe standard field generation system with antenna was implemented. For traceability we measured the associated quantities such as power, impedance, and attenuation of each component consisting of the field generation system. Evaluation of uncertainty in components providing traceability to the system was completed. The system is expected to generate standard field more than 30 V/m in the frequency range of 26.5 GHz to 40 GHz.

In this paper, we present calibration and uncertainty evaluation methods for the phase of a radio-frequency comb generator using a calibrated sampling oscilloscope. In addition, we present many solutions that are indispensable for the precise calibration of phase up to 50 GHz. First, we correct the sampling time error, which is the systematic error of the equivalent time sampling system. Second, the frequency response of the oscilloscope is de-convoluted from the measured pulse, and the impedance mismatch between the radio-frequency comb generator and the oscilloscope is calibrated. Finally, we present the calibrated phase of the radio-frequency comb generator and the measurement uncertainty, which demonstrated 95% confidence intervals within ±4.4° up to 50 GHz. The calibrated radio-frequency comb generator, which is traceable to SI units, is used to calibrate a nonlinear vector network analyzer, vector signal analyzer, and oscilloscope. Uncertainties are easily propagated to the measurement uncertainty of other apparatus since it is obtained in the form of covariance.

In this paper, we propose an estimation method using multiple in-phase and quadrature (IQ) signals of different frequencies to evaluate the sample-time errors in the sampling oscilloscope. The estimator is implemented by ODRPACK, and a novel iteration scheme is applied to achieve fast convergence without any prior information. Monte-Carlo simulation is conducted to confirm the proposed method. It clearly shows that the multiple IQ approach achieves more accurate results compared to the conventional method. Finally, the criteria for the frequency selection and the signal capture time are investigated.

본 논문에서는 샘플링 오실로스코프의 주파수 응답특성을 측정하는 방법을 제안하였다. 제안된 방법은 샘플링 오실로스코프의 계통오차인 시간축 왜곡 현상과 임피던스 부정합에 의한 영향을 교정할 수 있다. 또한 시간축 에러를 교정한 후에 발생하는 잔여 지터와 기준 펄스 발생 조건에 따라 변하는 scale factor의 정확...

This paper describes in detail how to characterize the response of a commercial real-time digital oscilloscope (RTDO) with traceability. The commercial RTDO usually employs a time interleaving ADC (TIADC) structure. Thus, aliasing is produced when the measurement is separated according to each ADC. As a result, it is difficult to obtain an accurate frequency response for each ADC. In this paper, we propose a method to avoid under-sampling issue, and it can achieve high sampling rate because it is similar to the equivalent sampling method.

This paper proposes an error vector magnitude (EVM) measurement method for a wideband code-division multiple-access source using a real-time oscilloscope. The EVM values are extracted from the measured waveform using a signal processing that finds the appropriate carrier phase and symbol timing. Measurement uncertainty is also evaluated based on a Monte Carlo simulation, where the errors from the real-time oscilloscope and the signal processing are taken into account. The measured EVM of a source at 900 MHz is (0.2586 ± 0.0040)%, (0.2617 ± 0.0060)%, and (0.2543 ± 0.0078)% at 95% confidence level when the real-time oscilloscope has a bandwidth of 2, 4, and 20 GHz, respectively.

This paper presents a methodology to accurately evaluate the spectral components of impulse signals which are delivered from an impulse generator through the measurement system. The complicated terms for uncertainty measurement of impulse spectrum amplitude and their analysis methods and experimental results are discussed. The expanded uncertainty of the impulse spectrum measurement is 0.015, which is believed to be the best domestic measurement capability and comparable to those of world class.

This paper describes how to calibrate key parameters (eye amplitude, eye height and eye width) of eye pattern generators using an oscilloscope which is directly traceable to basic physical quantities. Various correction methods are applied to reduce measurement uncertainties, which are estimated by use of the covariance matrix method.

In this paper, we propose estimation methods for the sample-time errors using multiple quadrature signals. To confirm the estimator, we perform Monte-Carlo simulation. The result shows that the proposed methods provide reliable confidence interval while the ODRPACK with reference two channels increases the outage as the independent jitter of each sampler is increased.

We present an optical sampling technique that enables exploration of mismatches of a microstrip transmission line based on reflection analyses of electromagnetic pulses. The external electro-optic sampling scheme with a minute crystal detects high-speed electrical pulses over arbitrary locations of a line with very low-intrusiveness. The temporal pulsed signals measured with an on-wafer optical probing system and the corresponding spectra are obtained to analyze the transfer characteristics of a microstrip transmission line with 20 GHz bandwidth. The spectro-temporal response was cross-checked with commercial instruments. Applications of this optical probing technique to explore mismatches at the terminal port — based on both time and frequency domain reflectometry analyses — are also presented.

A new calibration method of a power sensor for measuring the peak power of digitally modulated signals is introduced. This method uses an amplitude-modulated sine-wave source and is relatively simple to the currently available method that uses a digitally modulated signal source and an oscilloscope. Basic theory and calibration procedures for measuring the correction factor for peak power are described. Using a commercial peak power sensor that is calibrated with the proposed method, the peak power of a Global System for Mobile Communications at 900 MHz modulated signal is measured and compared with that measured by an oscilloscope. Various examples of choosing the calibration parameters are also discussed. The best uncertainty in the calibration of a peak power sensor is estimated to be 0.34% (k = 2).

In this paper, we introduce a simple and wideband characterization method for electric field probes using a transfer standard. As a transfer standard, a thin disk-type reference probe that can operate from 50 to 1000 MHz is used and calibrated using a micro transverse electromagnetic (mu-TEM) cell. A gigahertz transverse electromagnetic (GTEM) cell is used to generate a reference electric field. It has been shown that the uncertainty of the proposed method can be increased due to the imperfection of the field condition in the cell. According to the measurement result, the proposed characterization method for the electric probes agrees within 6.3%, compared with the method that uses the TEM cell and standard antennas in a fully anechoic chamber.

We have developed two coaxial-type microwave attenuation standards using the power ratio transfer method. One standard operates in the frequency range of 18 GHz to 26.5 GHz, and has a dynamic range of 80 dB. Its expanded uncertainty (k = 2) is estimated to be 0.01 dB/80 dB. The other operates in the frequency range of 26.5 GHz to 40 GHz, and has a dynamic range of 60 dB and an expanded uncertainty of 0.009 dB/60 dB. We present an example for calibration of a 40 dB step attenuator using the attenuation standard in a series radio-frequency substitution scheme. The expanded uncertainty (k = 2) is 0.01 dB including the mismatch uncertainty.

In this paper, we propose a broadband TEM horn antenna optimized using a genetic algorithm. The characteristics required for the TEM horn are the broad matching bandwidth from 2 GHz to 10 GHz and high gain in broadside with a small gain deviation within that bandwidth. In addition, a broadband balun is designed to improve the portability and to reduce the total size of the antenna. The measured return loss of the proposed TEM horn with the broadband balun is less than -10 dB(VSWR

This paper describes how to calibrate phase response of oscilloscopes, especially at low frequencies from 10 MHz to 1 GHz. The method uses the phase response of a standard mixer calibrated by three-mixer method as the reference phase. We describe basic principles and show results obtained using a balanced mixer and a real-time oscilloscope (1 GHz BW).

A novel method is proposed for the calibration of channel mismatch in a time-interleaved real-time digital oscilloscope (RTDO). A simple simultaneous equation is derived from the Fourier transform of the time-interleaved signals. Thus, it only requires a transfer function of time-interleaved ADCs (TIADCs), while most of previous works have employed additional filters. A measurement method for the transfer function of a commercial RTDO is also proposed. The accuracy of the calibration method is determined by the noise produced after the interleaving process. To validate the proposed method, we measure two-tone signals using a commercial RTDO. The calibrated results clearly show signals at spurious frequencies are substantially reduced.

This paper presents the radiation patterns of the monopole antenna mounted on the rectangular shaped structure and the coupling problem between transmit (Tx) and receiver (Rx) antennas obtained by using the FDTD method. A comparison of FDTD calculated results with the exact solution for cylindrical structure validates the accuracy of the algorithm. Using the developed FDTD code, the power radiated from the Tx port influences the Rx port at the nearby working frequency of 2 GHz. The magnitude of coupling effects in terms of scattering parameters has the highest value of about −40 dB within the 2–3.5-GHz frequency range. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 265–268, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11348

This paper proposes an error vector magnitude (EVM) measurement method for a wideband code-division multiple-access source using a real-time oscilloscope. The EVM values are extracted from the measured waveform using a signal processing that finds the appropriate carrier phase and symbol timing. Measurement uncertainty is also evaluated based on a Monte Carlo simulation, where the errors from the real-time oscilloscope and the signal processing are taken into account. The measured EVM of a source at 900 MHz is (0.2586 ± 0.0040)%, (0.2617 ± 0.0060)%, and (0.2543 ± 0.0078)% at 95% confidence level when the real-time oscilloscope has a bandwidth of 2, 4, and 20 GHz, respectively.

This paper shows an example of built-in shielding performance monitoring system which can be used in HEMP hardened facilities. A leaky wave coaxial cable is used for transmitting and receiving RF test signals.

We present a sampling technique that enables to explore transmission and reflection of fast electromagnetic pulses on a microstrip transmission line. Employing a minimally invasive optical sampling technique, temporal pulsed signals and the corresponding spectra are obtained for 20 GHz bandwidth.

A practical return loss measurement system that utilizes mature radio-over-fiber technology has been demonstrated. The S 11 of an antenna measured using frequency-multiplied optical links is in good agreement with that obtained using a conventional one.

A system to measure the noise temperature (NT) of noise sources is implemented in the frequency range of 18-26.5 GHz for the case where noise sources commercially available have only one nominal NT, e.g., 9500 K being equivalent to 15-dB excess noise ratio. For the Y-factor method, two noise sources, i.e., a noise source and another with a radio-frequency attenuator, serve as the standard noise sources. The noise power output of the noise sources are measured using a commercial noise figure measurement instrument. Measurement results are presented, and its uncertainty has been evaluated to be 0.23-0.25 dB (k = 2) .

A photonic-assisted reactive near-field scanner for planar antennas is presented. We, KRISS (Korea Research Institute of Standards and Science), have recently developed electro-optic sensors as all-dielectric electric field probes and utilized them for field imaging of antenna patterns. The performance of our system, as well as calibration of the system drift, are introduced by exploring 4 × 4 patch antenna arrays at the K-band.

A new calibration method of a peak power sensor measuring digitally modulated signals is introduced. This method uses an AM modulated sine wave source and is relatively simple to the currently available method which uses a digitally modulated signal source and an oscilloscope.

The nose-to-nose calibration method is applied to find the impulse response of broadband sampling oscilloscope (Tektronix SD-32, 50 GHz bandwidth). The result obtained is compared with the one measured using the swept-sine method and then used to calibrate the impulse response of an oscilloscope with 20 GHz bandwidth.

A calibration system of a 3.5 mm coaxial power sensor was implemented using transfer standards with 7 mm coaxial or K-band waveguide input connectors. A 7 mm-3.5 mm or WR42-3.5 mm adapter was used to form a combined transfer standard. The effective efficiency of the combined transfer standard was obtained. The 3.5 mm coaxial power sensor was calibrated using the well-known direct comparison method and measurement uncertainty was evaluated.

We have fabricated 2.7 m long conical antenna range that is used in the characterization of UWB antenna in the time domain. The transfer function of the system was measured to be within 3 dB of the expected value, in the frequency range of 100 MHz to 18 GHz.

In this paper, the authors discuss the suppression of differential mode noise induced by pulsed interference signals when ferrite cores are attached to a braided shield coaxial cable. They also suggest the locations of ferrite cores along the cable for the most effective suppression of differential mode noise induced by direct ESD, EFT/burst and surges. They experimentally investigated the effect of ferrite cores attachment in each.