New technological developments such as IoT, Artificial Intelligence and Blockchain are leading our “Data-driven society”, where data generated by physical devices are shared across multiple platforms to improve everyday services. This unique technological evolution also corresponds to new cybersecurity and data-protection risks and challenges as well as computational limitations, which could ultimately impact users’ experience, safety and privacy. The development of products and infrastructure offering long-term security guarantees and stronger computational capabilities is a global priority. Near-term, quantum technologies provide a radically new toolset to realize stronger encryption systems as well as improved randomized algorithms. One such technology is the development of a reliable high-speed and scalable quantum random number generator. In this article, a System in Package (SiP) integration and packaging process is analyzed to bring this component into the low cost and high-volume arena. The proposed SiP solution, combined with existing surface mount technology, offers numerous benefits, such as scalability, smaller physical size, less parasitic effects and lower cost. We will discuss component performance, with insights on interconnect lengths, the shielding effect and the impact of the encapsulants.
An analytic design-oriented model of phase and frequency modulated microwave optical links has been developed. The
models are suitable for design of broadband high dynamic range optical links for antenna remoting and optical
beamforming, where noise and linearity of the subsystems are a concern Digital filter design techniques have been
applied to the design of optical filters working as frequency discriminator, that are the bottleneck in terms of linearity for
these systems. The models of frequency modulated, phase modulated, and coherent I/Q link have been used to compare
performance of the different architectures in terms of linearity and SFDR.
We investigate AM/PM distortion models and compare them with baseband (BB) Volterra models. We show that the AM/PM model can be considered a special case of memoryless baseband Volterra models, and that adding memory can improve modeling accuracy by allowing the simulation of more complex nonlinearities. We report models of an LNA, a downconversion mixer, an upconversion mixer, and one class-AB Power Amplifier. All circuits are simulated using the 45nm STMicroelectronics CMOS process with Virtuoso, while the PA, with discrete devices, is simulated using ADS. Adding memory improves performance at the expense of increased numerical complexity: this makes real-time simulation and real-time calibration more expensive, so that there is a trade-off between complexity and accuracy or linearity (after calibration). Foreground calibration’s techniques only require the real-time computation of the correction (inverse) system’s output, whereas background calibration also requires the real-time estimation of the model coefficients, so the relevant complexity is that which is required during correction.
Many digital background calibration techniques exist which correct for offset, gain, timing and bandwidth mismatches in time-interleaved (TI) ADCs. Some require an additional reference channel, whereas others are blind and rely on the presence of a band where no signal is present (usually around the Nyquist frequency) or exploit other properties of the input signal. Blind calibration techniques, which don’t use a reference channel, are suitable for correction of commercial TI-ADCs, or TI-ADC systems using commercial ADCs as channels. Techniques employing additional channels require a more complex layout (especially for the clock tree) and need an additional ADC, whose overhead cost is significant, especially for 2- or 4- channel TI-ADCs. However, we show that the estimation process is faster and more accurate when a reference channel is present, and many different error models can be used (exploiting different points in the accuracy / complexity trade-off).
The paper focuses on an innovative spherical wave beam quadratic order processor, HSCS-1. It is an IP, Coulob Gauge based, to directly mesure, ∀t and in any single P ∀P (along the propagation axis too) the quadratic order Poynting Vector, with both the complex Linear Momentum (LiM) and Angolar Momentum (AnM) contributions, as well as the mutual quadratic order coherence function of any total or pseudo monochromatic observed beam wave.
The focoused spherical quadratic order method, directly mesure the spherical complex OAM (time and propagation axsis invariant) which is composed by the observed beam wave modes. Such solenoidal energy modes, becomes relevant to mesure far distance (as exemple: distance greater than billions of light years away) sources radiations.
Furthermore, HSCS-1 contemporary and directly measure the mutual (spatial as well as temporal) complex coherence of any general complex divergent or not strictly TEM (as example: TEM+DEM) observed radiations. Tipically TEM+DEM radiations are characterized by N=LPM+1 complex wave beam modes. N is the number of considered EM fields modes, as great as requested; N and L are integer, which values are internal to a closed interval [0; ∞]; P and M are integer, which values are internal to a closed interval [1; ∞]; n=0,1,…,N is the mode or beam channel index; with l=0, 1,…,L; p= 1,…, P; and m = 1,…,M; n=l=0 is the fundamental mode index).
Here are considered only the wave beam modes which satisfy the related Helmoltz monochromatic wave equation soluctions. As well known in Physics, only adopting a quadratic order energy processor it is possible ∀t to contemporary and directely mesure in P, ∀P(θ; Φ; z) and ∀(P-P0), both the proper P0 position and quantity of motion (proper space time variations), or by a Fourier Transformation to contemporary and directely mesure proper phase and frequency spectrum variations, of the observed general radiation source.
KEYWORDS: Transmission electron microscopy, Sensors, Polarization, Spherical lenses, Signal processing, Radio telescopes, Antennas, Prototyping, Electron tomography, Digital signal processing
The paper deals with the opportunity to introduce “Not strictly TEM waves” Synthetic detection Method (NTSM), consisting in a Three Axis Digital Beam Processing (3ADBP), to enhance the performances of radio telescope and sensor systems. Current Radio Telescopes generally use the classic 3D “TEM waves” approximation Detection Method, which consists in a linear tomography process (Single or Dual axis beam forming processing) neglecting the small z component. The Synthetic FEED ARRAY three axis Sensor SYSTEM is an innovative technique using a synthetic detection of the generic “NOT strictly TEM Waves radiation coming from the Cosmo, which processes longitudinal component of Angular Momentum too. Than the simultaneous extraction from radiation of both the linear and quadratic information component, may reduce the complexity to reconstruct the Early Universe in the different requested scales. This next order approximation detection of the observed cosmologic processes, may improve the efficacy of the statistical numerical model used to elaborate the same information acquired.
The present work focuses on detection of such waves at carrier frequencies in the bands ranging from LF to MMW. The work shows in further detail the new generation of on line programmable and reconfigurable Mixed Signal ASIC technology that made possible the innovative Synthetic Sensor. Furthermore the paper shows the ability of such technique to increase the Radio Telescope Array Antenna performances.
In this paper we present a methodology to calibrate and correct frequency-dependent errors in phased-array antennas with large signal bandwidth and large size. If the receivers are not narrow-band, the hypotheses of constant gain and group delay are not valid. If the frequency responses of the receivers are affected by mismatches, this will also impact directivity. Standard Amplitude and Phase Correction (APC) algorithms will not be effective in this case, and a more advanced complex FIR filtering algorithm is used. A transmitted signal is assumed to be known in order to provide a reference and estimate the optimal calibration coefficients of the FIR filters.
KEYWORDS: Antennas, Reflectors, Prototyping, Signal processing, Control systems, Sensors, Transmission electron microscopy, Metrology, Digital signal processing, Phase shifts
The paper deals with a possible use of the feed array present in a large antenna system, as a layer for measuring the antenna performance with a self-test procedure and a possible way to correct residual errors of the Antenna geometry and of the antenna distortions. Focus has been concentrated on a few key critical elements of a possible feed array metrology program. In particular, a preliminary contribution to the design and development of the feed array from one side, and the subsystem dedicated to antenna distortion monitoring and control from the other, have been chosen as the first areas of investigation. Scalability and flexibility principles and synergic approach with other coexistent technologies have been assumed of paramount importance to ensure ease of integrated operation and therefore allowing in principle increased performance and efficiency. The concept is based on the use of an existing feed array grid to measure antenna distortion with respect to the nominal configuration. Measured data are then processed to develop a multilayer strategy to control the mechanical movable devices (when existing) and to adjust the residual fine errors through a software controlled phase adjustment of the existing phase shifter The signal from the feed array is converted passing through a FPGA/ASIC level to digital data channels. The kind of those typically used for the scientific experiments. One additional channel is used for monitoring the antenna distortion status. These data are processed to define the best correction strategy, based on a software managed control system capable of operating at three different levels of the antenna system: reflector rotation layer, sub reflector rotation and translation layer (assuming the possibility of controlling a Stewart machine), phase shifter of the phased array layer. The project is at present in the design phase, a few elements necessary for a sound software design of the control subsystem have been developed at a technological demonstrator level while the ASIC board for generating the digital data stream has been fully developed. A prototype for control accurately the position of the sub-reflector up to a diameter of 5 meters (similar to the sub reflector size of a large antenna) using a Stewart mechanism is being planned. The selection strategy of the correction modes will depend on the dynamics of the phased array (i.e. the available bits of the A/D conversion). The reaction time allowed for the correction, depending on the error type and the inertia of the sub systems. Typically, the compensation can be divided among all the adjusting elements.
Phase noise models that describe the near-carrier spectrum in an accurate but insightful way are needed, to better optimize the oscillator design. In this paper we present a model to describe the effect of flicker noise sources on the phase noise of an oscillator, that can be applied both to linear oscillators and to nonlinear structures like relaxation and ring oscillators, so extending previous works that considered only the effect of the flicker noise superimposed to the control voltage of a VCO. In the phase noise of an oscillator we can separate the effect of high frequency noise sources, that can be described by a short-time-constant system, and the effect of low frequency noises (mostly flicker sources), described by a system with time constants much slower than the oscillation period. Flicker noise has been considered to cause a change in the circuit bias point; this bias point change can be mapped in a shift of the oscillation frequency by exploiting Barkhausen conditions (for linear oscillators) or obtaining this link by simulations. The power spectral density of the oscillator can then be obtained as the probability distribution of the oscillation frequency, starting from the flicker noise probability distribution. If the effect of high frequency noise sources is also taken into account, the overall oscillator spectrum can be obtained as a convolution of the spectrum due to flicker sources with the Lorentzian-shaped spectrum due to white noise sources, in analogy with the description of inhomogeneous broadening of laser linewidth.
A monolithic Clock and Data Recovery (CDR) circuit for SDH STM-16 (2.5 Gb/s) digital receivers has been designed and fabricated using Maxim GST-2 27 GHz Silicon bipolar technology. The main functions carried out by the IC are: signal amplification (40 dB) and limitation, clock recovery and decision. The design is intended to achieve a complete 2.5 Gb/s receiver by using the IC and a low noise preamplifier (transimpedance stage), mounted in a DIL package. The integrated circuit comprises about 400 active devices, used both for analog and digital blocks, and uses two supply voltages of 5 and -4.5 V. The input port is decoupled by external capacitors and matched to 50 (Omega) using on-chip resistors, whereas clock and data outputs are open collector type. The die size is 2 X 2 mm2 and the chip has been packaged using a TQFP 48 pins plastic package. Measurements under 231-1 PRBS data stream have shown an input sensitivity below 5 mVpp, rms output jitter below 7 ps and total power consumption of 0.8 W.
We present the design and realization of two optical front- ends in the bandwidth 0.5-10 GHz and with a transimpedance gain greater than 60 dB. The two amplifiers implement a lossy matching architecture with an interstage matching and a matched feedback architecture with a frequency controlled local feedback. We realized two hybrid circuits on an alumina substrate. A p-i-n photodiode has been placed on a ceramic substrate together with the three stage amplifier block. We propose a comparison between the two architecture taking into account the effects of the photodiode hybrid assembly. The parasitic link effects on the expected performances of the different architectures. We firstly measured on the photodiode hybrid circuit to verify its model: the response was not as flat as expected from the datasheet. Therefore we had to equalize the photodiode frequency response by means of an input reactive network.
A new differential topology of optical receiver which is based on a differential sensing of the output current of the photodiode is presented in this paper. The receiver proposed here is made by a P-I-N photodiode and two amplifiers, each one amplifies the current furnished by a lead of the photodiode. It is intended for digital transmission systems which require a low-pass type response. By adopting a wide band transimpedance amplifier, this topology can increase the sensitivity of the optical receiver by 3 dB as well as the output level which is increased by 6 dB, and therefore reduces the gain requirement to the transimpedance amplifier and to the main amplifier.
The effect of shunt-shunt feedback in monolithic transimpedance amplifiers for multiGbit per second optical receivers on the input impedance is considered in this paper. The main transfer function to be optimized is the transimpedance, but the input impedance should be taken into careful consideration to avoid unexpected peaking effects which can be a cause of performance degradation. The interconnection technique used to couple the photodiode to the MMIC amplifier has to be properly chosen in conjunction with the performance of the amplifier as current sink at the input port. We propose a design methodology based on the root-locus technique which can help the designer in the optimization of this kind of circuit with particular regard to the input peaking effects.
The performance of bandpass optical receivers can be improved using a lossless equalizer between the photodiode and the amplifier, as a consequence of the mismatch between the source and the input section of the amplifier. We propose two design approaches based on noise matching and on power matching, as well as a performance evaluation criterion to make comparisons between these different techniques. We have found the limit of noise performance of the approaches at a single frequency, and an upper bound, derived from the Bode-Fano limit, in a wide-band application for the power matching approach.
The following technique compares GaAs monolithic processes regarding the requirement of transimpedance amplifiers to be used in optical front-ends. This technique uses a lumped element model of the forward amplifier to establish relationships between the small signal model of the devices which form the forward amplifier and the closed loop performance, as well as the root locus representation of the loop gain transfer function to set clear constraints to the frequency response. The comparison is performed by establishing a set of constraints to ensure the effectiveness of solution found and to reduce the number of degrees of freedom in this problem. This comparison has been carried out by taking into consideration the presence of the parasitic capacitance of the photodiode which plays an important role in the bandwidth performance.
In this paper we present the design approach and measurements of an optical receiver suited for IM-DD systems operating up to 2.5 Gbit/s bit-rate. The receiver is composed by a Ga-As MMIC transimpedance amplifier and a commercially available pin photodiode. The MMIC amplifier has been fabricated and it has been measured on wafer, showing a -3 dB cut- off frequency of 2.6 GHz, stability and low sensitivity to bias variations.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.