Nominal Gain Research Articles

Low-Density Lattice Codes for Inter-Symbol Interference Channels

Low-density lattice codes (LDLC) designed for inter-symbol interference (ISI) channels are proposed in this paper, including the node-by-node belief propagation (BP) decoding algorithm and the construction of LDLC codes for ISI channels. A theorem is presented to illustrate that the nominal coding gain of LDLC codes can be increased by introducing ISI into the primary codes. Shaping operation must be used to minimize the power of transmitted lattice points and to utilize the potential nominal coding gain. By using a semi-analytical density evolution method based on all-zero lattice assumption elements of parity check matrix are optimized. Simulation results show that error performance of LDLC code at dimension 10,000 is 1.1 dB from the capacity when the spectral efficiency is 1 bps/Hz.

MATERIALS INSERTION LOSS AT 2.4, 3.3 AND 5.5 GHZ BANDS

The insertion loss of different materials is measured at 2.4, 3.3 and 5.5 GHz bands. Directive antennas with a nominal gain of 19 dB are used in the measurement campaign. The height of the antennas has been selected to have the minimum possible reflection from around surfaces. Metallic door with porthole window, metallic grid, glass window, human beings and tree’s insertion loss are measured. The metallic grid presents a band pass filter function with a resonance frequency between 3.2 to 3.3 GHz. Other materials have an insertion loss that increases with the increment of the operating frequency.

MATERIALS' INSERTION LOSS AT THREE FREQUENCY BANDS

The insertion loss of difierent materials is measured at 2.4, 3.3 and 5.5GHz bands. Directive antennas with a nominal gain of 19dB are used in the measurement campaign. The height of the antennas has been selected to have the minimum possible re∞ection from around surfaces. Thick concrete wall, thick concrete column and tree's insertion loss are measured. It is noticed that the insertion loss increases with the increment of the operating frequency. For tress, the insertion loss for the lea∞ess tress is 6 to 10dB lower than the deciduous trees.

Response of CMS avalanche photo-diodes to low energy neutrons

The response of the Avalanche Photo-diodes (APDs) installed in the CMS detector at the LHC to neutrons from 241AmBe and 252Cf sources is reported. Signals in size equivalent to those of up to 106 photo-electrons with the nominal APD gain are observed. Measurements with an APD with the protective epoxy coating removed and with the source placed behind the APD show that there is an important response due to recoil protons from neutron interactions with the hydrogen in the epoxy, in addition to signals from neutron interactions with the silicon of the diode. The effective gain of these signals is much smaller than the diode's nominal gain.

An Ultra-Low Voltage, Low-Noise, High Linearity 900-MHz Receiver With Digitally Calibrated In-Band Feed-Forward Interferer Cancellation in 65-nm CMOS

We present an ultra-low voltage, highly linear, low noise integrated CMOS receiver operating from a 0.6-V supply. The receiver incorporates programmable, in-band feed-forward interferer cancellation at the baseband to obtain high linearity and low noise operation at ultra-low supply voltages. Being able to reject adjacent channel or far-out blockers, the digitally calibrated interferer cancellation improves the IIP3 and IIP2 by more than 13 dB and 8 dB respectively with very little impact on the receiver noise figure. As such, it breaks the trade-off between linearity and noise figure, making it possible to use a high-gain RF front-end to achieve low noise figure without affecting the linearity of the ultra-low voltage baseband circuits. The 0.6-V 900-MHz direct-conversion receiver prototype integrates a differential LNA, RF transconductors, linear quadrature current driven passive mixers, feed-forward interferer cancellation circuits, baseband variable gain transimpedance amplifiers and second-order channel-select filters. It has a nominal conversion gain of 56.4 dB, noise figure of 5 dB, IIP3 of -9.8 dBm and IIP2 of 21.4 dBm. The receiver operates reliably from 0.55-0.65 V, consumes 26.4 mW and occupies an active area of 1.7 mm2 in a 65-nm low-power CMOS process, of which the feed-forward interferer cancellation circuits consume 11.4 mW and occupies 0.43 mm2 .

Variable-Gain, Low-Noise Amplification for Sampling Front Ends

This paper presents a low-noise front-end amplifier with configurable gain, targeting the recording of small signals, such as the electrocardiogram (ECG) or electroneurogram (ENG). The circuit consists of a continuous-time input stage using lateral bipolar transistors realized in complementary metal-oxide semiconductor (CMOS) technology followed by a switched-capacitor integrating stage. The voltage gain is adjustable by varying the phase delay between two system clocks. Simulated and measured results for a chip fabricated in 0.35-μm CMOS technology are reported. The amplifier occupies an active area of 0.064 mm(2), yields a nominal gain of 630 V/V with more than a 50-dB tuning range, less than 16 nVrms/√Hz input noise and a common-mode rejection of more than 97 dB. Its power consumption is 280 μW with a ±1.5-V supply.

An Optimum Body Biasing for Gain and Linearity Control in CMOS Low-Noise Amplifiers

In this paper, an optimum body biasing for gain and linearity control in CMOS Low Noise Amplifier (LNA) is discussed. A digitally controlled highly linear CMOS LNA has been designed and implemented in a 0.13 μm CMOS process. An off chip Digital to Analog Converter (DAC) is used to generate the proper body bias voltage corresponding to a maximum of the input referred third order intercept point (IIP3). The LNA is suitable for reconfigurable purposes due to its smooth control of gain and linearity. It is dedicated to wireless sensor network applications in the 2.4 GHz ISM Band. The circuit achieves 12.4 dB nominal gain, 4.2 dB noise figure (NF), and ―1 dBm IIP3 while drawing 3.1 mA at a 1 V supply. When adjusting the body bias to ―0.55 V, the IIP3 peaks at 6 dBm for a 1.7 mA current consumption. The gain and NF are 8.9 dB and 6.2 dB respectively.

Complex Oscillation-Based Test and Its Application to Analog Filters

Testing is a critical factor for modern large-scale mixed-mode circuits. Strategies for mitigating test cost and duration include moving significant parts of the test hardware on-chip. This paper presents a novel low-overhead approach for design for test and built-in self-test of analog and mixed-mode blocks, derived from the oscillation-based test framework. The latter is enhanced by the use of <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">complex</i> oscillation regimes, improving fault coverage and enabling forms of parametric or specification-based testing. This technique, initially proposed targeting large subsystems such as A/D converters, is here illustrated at a much finer granularity, considering its application to analog-filter stages, and also proving its suitability to backfit existing designs. The simple case of a switched-capacitor second-order bandpass stage is used for illustration discussing how deviations from nominal gain, central frequency, and quality factor can be detected from measurements not requiring A/D stages. A sample design is validated by simulations run at the layout level, including Monte Carlo analysis and simulations based on random fault injections.

A 240-MHz Low-Pass Filter With Variable Gain in 65-nm CMOS for a UWB Radio Receiver

An integrated fifth-order continuous-time low-pass filter for a WiMedia ultrawideband radio receiver is described in this paper. The prototype filter is realized with a passive pole at the filter input and a fourth-order leapfrog filter in which the gm-C technique with pseudodifferential transconductors is used. The transconductors do not include internal nodes, and they are designed to have a nominal 26-dB dc gain, of which process, voltage, and temperature variations are controlled by means of a negative resistance circuit. The losses of the low-dc-gain filter integrators are already taken into account in the filter synthesis. The passband edge frequency of the implemented filter is 240 MHz in order to receive multiband-orthogonal-frequency-division-multiplexing signals using the direct-conversion topology. The voltage gain of the filter can be controlled from 9 to 43 dB in the 1-dB gain steps. The filter achieves a 7.8-nVradicHz input-referred noise density, a -8-dBV out-of-band third-order intermodulation intercept point, and a +15-dBV out-of-band second-order intermodulation intercept point. The circuit uses a 1.2-V supply and has been fabricated in a modern 65-nm CMOS technology.

A Scalable 6-to-18 GHz Concurrent Dual-Band Quad-Beam Phased-Array Receiver in CMOS

This paper reports a 6-to-18 GHz integrated phased- array receiver implemented in 130-nm CMOS. The receiver is easily scalable to build a very large-scale phased-array system. It concurrently forms four independent beams at two different frequencies from 6 to 18 GHz. The nominal conversion gain of the receiver ranges from 16 to 24 dB over the entire band while the worst-case cross-band and cross-polarization rejections are achieved 48 dB and 63 dB, respectively. Phase shifting is performed in the LO path by a digital phase rotator with the worst-case RMS phase error and amplitude variation of 0.5deg and 0.4 dB, respectively, over the entire band. A four-element phased-array receiver system is implemented based on four receiver chips. The measured array patterns agree well with the theoretical ones with a peak-to-null ratio of over 21.5 dB.

What Makes Housing Owners Hold?

Many financial studies have produced evidence of the disposition effect - investors tend to sell assets with nominal gains and keep those with nominal losses. This effect is predominantly explained by the prospect theory, which postulates asymmetric preferences towards gains against losses. This study aims to examine what factors determine housing owners to hold. We postulate that holding period is a function of 1) household characteristics, 2) property attributes, and 3) disposition effect of nominal gain or loss. These postulates are tested empirically by a panel data set of housing transactions in one of the largest estate in Hong Kong of 15,235 transactions from 1991 to 2005. The results show that losers tend to hold 32 months longer than winners, but this magnitude is found to be much longer than other similar studies in securities trading. We contend that moving costs and asymmetric information in housing markets is responsible for such a difference.

Characterization of avalanche photodiodes (APDs) for the electromagnetic calorimeter in the ALICE experiment

The Electromagnetic Calorimeter (EMCal) of the ALICE experiment at LHC will extensively make use of avalanche photodiodes (APDs) for the readout of scintillation light. The large sensitive area, high quantum efficiency and low dark current make this type of photosensors well-suited for the EMCal requirements. A testing activity is currently in progress in order to characterize the main properties of these APDs and find the best working conditions. Fundamental tasks are the individual test of all APDs after presetting their nominal gain via the bias control and the study of APD gain coefficients as a function of the applied bias voltage and temperature. An overview of the adopted procedure will be presented, together with a description of preliminary results obtained on a first sample of APDs during the testing activity.

Right-direct (BI) type wide bandpass SC ladder filter with compensation for finite amplifier gain and offset voltage

In this paper gain- and offset-compensated (GOC) modification of a sixth-order right-direct (BI) type wide bandpass switched-capacitor (SC) ladder filter is proposed. It is based on the use of simple and fast operational amplifiers (op amps) with low but precisely known and stable dc gain A. At first, the conventional integrators in the filter are replaced with GOC integrators and the unswitched capacitors in the capacitive loops are split into two capacitors. Subsequently, the nominal op amps gain value A0 is taking into account in the capacitance sizing of some appropriately chosen capacitors. .

Parasitic diffuse reflection in a Fourier transform spectrometer yielding subharmonic ghosts and line-shape distortion

When using a high-resolution Fourier transform spectrometer (FTS) in a cube-corner configuration, subharmonic ghosts are observed in the spectrum. These ghosts are attributable to parasitic diffuse reflections on the mirrors of the FTS arm. The reflected beams skip a part of the interferometer and travel a different path from the main beam thus experiencing a smaller optomechanical gain. These reflections are present in the reference laser channel as well as on the measurement channel, and each affect the estimated spectrum differently. The sampling grid generated by the reference laser has periodic errors that are synchronized with the fringe signal. The measured spectrum can therefore exhibit sampling jitter ghosts at submultiples of the reference laser wavenumber in addition to its own additive subharmonics. The diffuse reflection experiencing the nominal optomechanical gain, such as in a plane-mirror configuration, will impact directly on the instrument line shape and on the radiometric accuracy of the spectrometer since some radiation is not propagating at the expected angles in the instrument.

Thermopile radiometer signal conditioning for surface atmospheric radiation measurements

A highly stable microvolt amplifier for use with atmospheric broadband thermopile radiometers is described. The amplifier has a nominal gain of 500, for bipolar input signals in the range ±10mV from a floating source. The noise level at the input is less than 5μV (at 100kΩ input impedance), permitting instantaneous diffuse solar radiation measurements to 0.5Wm−2 resolution with 12bit analog to digital conversion. The temperature stability of gain is better than 5ppm∕°C (−4to20°C). Averaged over a decade of use, the long term drift of the amplifier gain is less than ∼0.02%∕yr. As well as radiometers measuring solar and terrestrial radiations, the amplifier has also been successfully used with low level signals from thermocouples and ground heat flux plates.

High-CMRR Current Amplifier Architecture and Its CMOS Implementation

A novel current operational amplifier, in which the traditionally adopted input current follower is replaced by an input stage that exhibits current gain and single-input-to-differential-output conversion, is presented. Due to this, increased values of both dc gain and common-mode rejection ratio (CMRR) are obtained in the overall amplifier. A CMOS implementation, along with postlayout simulations, which are in good agreement with expected data, is also included. The proposed design is supplied with 2.5 V, dissipates 0.7 mW, and provides a nominal dc gain, a gain-bandwidth product, and a CMRR (at dc) of 72 dB, 28 MHz, and greater than 100 dB, respectively

Optical Gain and Absorption of Quantum Dots Measured Using an Alternative Segmented Contact Method

An alternative segmented-contact method for accurate measurement of the optical gain and absorption of quantum-dot and quantum-dash active materials with small optical gain is reported. The usual error from unguided spontaneous emission is reduced by subtracting signals acquired from three independently controlled sections as opposed to just two found in the conventional technique. The quantum-dot gain spectra are measured to a precision of less than 0.2 cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> at nominal gain values below 2 cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> , and gain spectrum of quantum-dash sample is calculated with an error less than 0.3 cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> at a gain less than 1 cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> . These accuracies are checked with a self-calibrating method. The internal optical mode loss measurement is also described

Analogue electronic circuit diagnosis based on ANNs

Feed-forward artificial neural networks (ANNs) have been applied to the diagnosis of nonlinear dynamic analogue electronic circuits. Using the simulation-before-test (SBT) approach, a fault dictionary was first created containing responses observed at all inputs and outputs of the circuit. The ANN was considered as an approximation algorithm to capture mapping enclosed within the fault dictionary and, in addition, as an algorithm for searching the fault dictionary in the diagnostic phase. In the example given DC and small signal frequency domain measurements were taken as these data are usually given in device’s data-sheets. A reduced set of data per fault (DC output values, the nominal gain and the 3 dB cut-off frequency, measured at one output terminal) was recorded. Soft (parametric) and catastrophic (shorts and opens) defects were introduced and diagnosed simultaneously and successfully. Large representative set of faults was considered, i.e., all possible catastrophic transistor faults and qualified representatives of soft transistor faults were diagnosed in an integrated circuit. The generalization property of the ANNs was exploited to handle noisy measurement signals.

On the Monotonicity and Linearity of Ideal Radix-Based A/D Converters

Both cyclic and pipelined analog-to-digital (A/D) converters are getting more and more popular, as they are relatively easy to design and either have a high throughput (pipelined converters) or small area- and power-consumption (cyclic/algorithmic converters). To avoid saturation and to ensure effective digital calibration, in the analog stage(s) of these converters, instead of the ideal two, often a smaller nominal gain (called radix number) is used. In this paper, it is shown that these radix-based converters have nonmonotonic output and finite linearity. The causes of these phenomena are discussed in detail. Fully digital method is suggested to remove nonmonotonic code transitions and estimation on the maximum differential nonlinearity of the ideal converter as a function of the number of cycles is presented.

Four-arm 2nd- mode slot spiral antenna with simple single-port feed

The design and performance of a novel 4-arm equiangular slot spiral antenna operating in the 2nd mode are discussed in this letter. A straightforward feeding method consisting of a single vertical coaxial probe and no underlying mode forming network is proposed. Along with inherent simplicity, this feed enables design flexibility with respect to the slot-to-metal ratio, growth rate, and other spiral parameters. Numerical tools including an in-house finite element-boundary integral (FE-BI) code and Ansoft HFSS are used in designing the antenna. Good performance over an octave bandwidth is achieved, with axial ratio and WoW less than 3 dB, nominal gain of 3 dBic, and VSWR less than 1.6. Performance is verified with measurements. A method for increasing the bandwidth up to 3 : 1, which is the theoretical value determined by the excitation of the first higher order mode, is demonstrated computationally.