The probe used in the conventional SAR measurement is usually calibrated in a well filled with tissue-equivalent liquid surrounded by a rectangular waveguide and a matching dielectric window in the frequency range from 800 MHz to 3 GHz. However, below 800 MHz, the waveguides are too large to be used for the calibration. Therefore, we have developed another technique of calibrating the SAR-probe, that is, relating the output voltage of the probe to the field intensity produced by a reference antenna in the tissue-equivalent liquid by using two-antenna method. In this paper, the calibration system using the reference dipole antennas in the liquid at 450 MHz, 900 MHz and 2450 MHz is presented and far-field gain of the reference antenna and calibration factor of the SAR-probe are measured and compared with those obtained by using the conventional waveguide system.

A MB-OFDM UWB transmitter with on-chip transformer and LO leakage calibration for WiMedia bandgroup 1 is presented. The measurements show a gain-flatness of 1 dB, an LOLRR of -53 dBc/-43 dBc (wi/o cali), an EVM of 2.2% with a power consumption of 22 mW and an area of 1.26 mm2.

Microwave/millimeter-wave phase and amplitude characteristics of the optically controlled phased array antenna with a different SMF for each antenna feed were measured. Suitable phases for the beam steering can be realized by the adjustment of the LD wavelength independently with multiple SMFs. In addition to the phase, amplitude of each antenna feed can be controlled stably using LD current without phase variation. Furthermore, effectiveness of the calibration method of the phased array using multiple SMFs by LD wavelength adjustment is experimentally verified. Excellent microwave/millimeter-wave phase characteristics using 2- and 3-element optically controlled phased array feed were experimentally demonstrated with calibration of the phases. Phase characteristics of the array using multiple SMFs were also compared with that using a single SMF experimentally.

The waveguide-penetration method is a method to measure the electrical properties of materials. In this method, a cylindrical object pierces a rectangular waveguide through a pair of holes at the centre of its broad walls. Then, the complex permittivity and permeability of the object are estimated from measured S-parameters after TRL calibration. This paper proposes a new calibration algorithm for the waveguide-penetration method. Reference materials with known electrical properties are fabricated in cylindrical shapes to fit into the holes in the waveguide and are used as calibration standards. The algorithm is formulated using the property of equal traces in similar matrices, and we show that at least two reference materials are needed to calibrate the system. The proposed algorithm yields a simpler means of calibration compared to TRL and is verified using measurements in the S-band. Also, the error sensitivity coefficients are derived. These coefficients give valuable information for the selection of reference materials.

This paper presents a user-calibration-free method for estimating the point of gaze (POG). This method provides a fast and stable solution for realizing user-calibration-free gaze estimation more accurately than the conventional method that uses the optical axis of the eye as an approximation of the visual axis of the eye. The optical axis of the eye can be estimated by using two cameras and two light sources. This estimation is carried out by using a spherical model of the cornea. The point of intersection of the optical axis of the eye with the object that the user gazes at is termed POA. On the basis of an assumption that the visual axes of both eyes intersect on the object, the POG is approximately estimated using the binocular 3D eye model as the midpoint of the line joining the POAs of both eyes. Based on this method, we have developed a prototype system that comprises a 19″ display with two pairs of stereo cameras. We evaluated the system experimentally with 20 subjects who were at a distance of 600 mm from the display. The root-mean-square error (RMSE) of measurement of POG in the display screen coordinate system is 1.58.

Distance to target is fundamental and very important information in numerous engineering fields. Many distance measurement methods using sound use the time delay of a reflected wave, which is measured in reference to the transmitted wave. This method, however, cannot measure short distances because the transmitted wave, which has not attenuated sufficiently by the time the reflected waves are received, suppresses the reflected waves for short distances. Therefore, we proposed an acoustic distance measurement method based on the interference between the transmitted wave and the reflected waves, which can measure distance in a short range. The proposed method requires a cancellation processing for background components due to the spectrum of the transmitted wave and the transfer function of the measurement system in real environments. We refer to this processing as background components cancellation processing (BGCCP). We proposed BGCCP based on subtraction or whitening. However, the proposed method had a limitation with respect to the transmitted wave or additive noise in real environments. In the present paper, we propose an acoustic distance measurement method based on the new BGCCP. In the new BGCCP, we use the calibration of a real measurement system and the whitening processing of the transmitted wave and introduce the concept of the cepstrum to the proposed method in order to achieve robustness. Although the conventional BGCCP requires the recording of the transmitted wave under the condition without targets, the new BGCCP does not have this requirement. Finally, we confirmed the effectiveness of the proposed method through experiments in real environments. As a result, the proposed method was confirmed to be valid and effective, even in noisy environments.

This paper proposes an active-RC filter that achieves a wide pseudo-continuous bandwidth-tuning range and a wide gain range with fine steps using a novel switched resistor architecture. A channel-selection filter with the proposed resistor bank is designed for a multi-mode mobile-TV receiver with the 6th order Chebyshev-I topology. The bandwidth, 0.5–6 MHz with 5% steps, supports multiple mobile-TV standards with sufficient margins for process and temperature variations. The filter also accomplishes a 30-dB variable gain range with 6-dB steps, and it relaxes the dynamic range requirement of a succeeding programmable gain amplifier. The power consumption of the filter, 3.4–5.0 mW, is adjustable according to the bandwidth and the signal level. The filter was fabricated with on-chip bandwidth-calibration circuitry in 0.18-µm CMOS and occupied 0.81 mm2.

This brief paper describes a background calibration algorithm for a pipelined ADC with an open-loop amplifier using a Split ADC structure. The open-loop amplifier is employed as a residue amplifier in the first stage of the pipelined ADC to realize low power and high speed. However the residue amplifier as well as the DAC suffer from gain error and non-linearity, and hence they need calibration; conventional background calibration methods take a long time to converge. We investigated the split ADC structure for its background calibration with fast convergence, and validated its effectiveness by MATLAB simulation.

This paper introduces a tensorial representation of multiple cameras with arbitrary curvilinear motions. It enables us to define a multilinear relationship among image points derived from non-rigid object motions viewed from multiple cameras with arbitrary curvilinear motions. We show the new multilinear relationship is useful for generating images and reconstructing 3D non-rigid object motions viewed from cameras with arbitrary curvilinear motions. The method is tested in real image sequences.

In this paper, a 65 nm 1.2 V 7-bit 1GSPS folding-interpolation A/D converter with a digitally self-calibrated vector generator is proposed. The folding rate is 2 and the interpolation rate is 8. A self-calibrated vector generation circuit with a feedback loop and a recursive digital code inspection is described. The circuit reduces the variation of the offset voltage caused by process mismatches, parasitic resistors, and parasitic capacitances. The chip has been fabricated with a 65 nm 1-poly 6-metal CMOS technology. The effective chip area is 0.87 mm2 and the power consumption is about 110 mW with a 1.2 V power supply. The measured SNDR is about 39.1 dB when the input frequency is 250 MHz at a 1 GHz sampling frequency. The measured SNDR is drastically improved in comparison with the same ADC without any calibration.

This paper presents a well-structured modified Booth encoding (MBE) multiplier which is applied in the design of a reconfigurable multiply-accumulator (MAC) core. The multiplier adopts an improved Booth encoder and selector to achieve an extra-row-removal and uses a hybrid approach in the two's complementation circuit to reduce the area and improve the speed. The multiplier is used to form a 32-bit reconfigurable MAC core which can be flexibly configured to execute one 3232, two 1616 or four 88 signed multiply-accumulation. Experimentally, when implemented with a 130 nm CMOS single-Vt standard cell library, the multiplier achieved a 15.8% area saving and 11.7% power saving over the classical design, and the reconfigurable MAC achieved a 4.2% area and a 7.4% power saving over the MAC design published so far if implemented with a mixed-Vt standard cell library.

We consider RFID bookshelves, which detect the location of books using RFID. An RFID bookshelf has the antennas of RFID readers in the boards, and detects the location of an RFID tag attached to a book. However, the accuracy is not good with the experience of the existing system, and sometimes reads the tag of the next or even further area. In this paper, we propose a method to improve the location detection using naive Bayes classifer, and show the experimental result. We obtained 78.6% of F-measure for total 12658 instances, and show the advantage against the straightforward approach of calculating the center of gravity of the read readers. More importantly, we show the performance is less dependent of a change of layouts and a difference of books by leave-1-layout/book-out cross validation. This is favorable for the feasibility in library operation.

An algorithm for the discrimination between human upstairs and downstairs using a tri-axial accelerometer is presented in this paper, which consists of vertical acceleration calibration, extraction of two kinds of features (Interquartile Range and Wavelet Energy), effective feature subset selection with the wrapper approach, and SVM classification. The proposed algorithm can recognize upstairs and downstairs with 95.64% average accuracy for different sensor locations, i.e. located on the subject's waist belt, in the trousers pocket, and in the shirt pocket. Even for the mixed data from all sensor locations, the average recognition accuracy can reach 94.84%. Experimental results have successfully validated the effectiveness of the proposed method.

High resolution direction-of-arrival (DOA) estimation algorithm for array antennas becomes popular in these days. However, there are several error factors such as mutual coupling among the elements in actual array. Hence array calibration is indispensable to realize intrinsic performance of the algorithm. In the many applications, it is preferable that the calibration can be done in the practical environment in operation. In such a case, the incident wave becomes coherent multipath wave. Calibration of array in the multipath environment is a hard problem, even when DOA of elementary waves is known. To realize array calibration in the multipath environment will be useful for some applications even if reference signals are required. In this report, we consider property of reference waves in the multipath environment and derive a new calibration technique by using the multipath coherent reference waves. The reference wave depends on not only the DOA but also complex amplitude of each elementary wave. However, the proposed technique depends on the DOA only. This is the main advantage of the technique. Simulation results confirm the effectiveness of the proposed technique.

A 9-bit 100-MS/s successive approximation register (SAR) ADC with low power and small area has been implemented in 65-nm CMOS technology. A tri-level charge redistribution technique is proposed to reduce DAC switching energy and settling time. By connecting bottom plates of differential capacitor arrays for charge sharing, extra reference voltage is avoided. Two reference voltages charging and discharging the capacitors are chosen to be supply voltage and ground in order to save energy and achieve a rail-to-rail input range. Split capacitor arrays with mismatch calibration are implemented for small area and small input capacitance without linearity degradation. The ADC achieves a peak SNDR of 53.1 dB and consumes 1.46 mW from a 1.2-V supply, resulting in a figure of merit (FOM) of 39 fJ/conversion-step. The total active area is 0.012 mm2 and the input capacitance is 180 fF.

The letter proposes a novel binary vulnerability analyzer for executable programs that is based on the Hidden Markov Model. A vulnerability instruction library (VIL) is primarily constructed by collecting binary frames located by double precision analysis. Executable programs are then converted into structurized code sequences with the VIL. The code sequences are essentially context-sensitive, which can be modeled by Hidden Markov Model (HMM). Finally, the HMM based vulnerability analyzer is built to recognize potential vulnerabilities of executable programs. Experimental results show the proposed approach achieves lower false positive/negative rate than latest static analyzers.

A Q-enhanced 8th order CMOS active bandpass filter is presented employing a novel two-stage self-calibration technique. The proposed active filter shows the better out-band attenuation performance than other reported CMOS active bandpass filters. The proposed calibration method enables the stable filtering operation affected by neither the input power variation nor the strong interference power. It is fabricated using 65 nm CMOS process. The measured 3 dB bandwidth is 54 MHz at 2.37 GHz. The insertion loss is 2.9 dB and the out-band attenuation is 27.5 dB at 15 MHz offset frequency. The performance of the filter remains unchanged for 5% supply voltage variations.

We succeeded to develop a reference light source in the range of very low luminance using a double integrating sphere system, and calibrated a commercial spectrophotometer below 110-5 cd/m2 levels, which is 1/100 lower than the specified limit for measurement. And we improved measurements in the ultra low luminance range of displays using the calibrated commercial spectrophotometer and a dark sphere to suppress the influence of the surround.

We present self-calibration techniques for an interleaved SAR (Successive Approximation Register) ADC. The calibration technique is based on hardware corrections for linearity of single stage, gain error and mismatch errors of parallel ADCs. The 4-interleaved 11-bit ADC has been fabricated in a 0.18-µm CMOS process. Using the calibrations, measurement and calculation results show that the differences of ramp characteristic among the 4-interleaving ADC can be decresased to under 0.63 LSB.

This manuscript introduces a pointing interface for a tabletop display with a reflex in eye-hand coordination. The reflex is a natural response to inconsistency between kinetic information of a mouse and visual feedback of the mouse cursor. The reflex yields information on which side the user sees the screen from, so that the screen coordinates are aligned with the user's position.