Fast Fourier Transform

Resonance-based wireless power delivery is an efficient technique to transfer power over a relatively long distance. This technique typically uses four coils as opposed to two coils used in conventional inductive links. In the four-coil system, the adverse effects of a low coupling coefficient between primary and secondary coils are compensated by using high-quality (Q) factor coils, and the efficiency of the system is improved. Unlike its two-coil counterpart, the efficiency profile of the power transfer is not a monotonically decreasing function of the operating distance and is less sensitive to changes in the distance between the primary and secondary coils. A four-coil energy transfer system can be optimized to provide maximum efficiency at a given operating distance. We have analyzed the four-coil energy transfer systems and outlined the effect of design parameters on power-transfer efficiency. Design steps to obtain the efficient power-transfer system are presented and a design example is provided. A proof-of-concept prototype system is implemented and confirms the validity of the proposed analysis and design techniques. In the prototype system, for a power-link frequency of 700 kHz and a coil distance range of 10 to 20 mm, using a 22-mm diameter implantable coil resonance-based system shows a power-transfer efficiency of more than 80% with an enhanced operating range compared to ~40% efficiency achieved by a conventional two-coil system.

Design and Optimization of Resonance-Based Efficient Wireless Power Delivery Systems for Biomedical Implants

This paper describes the development of a high-density electronic interface to the central nervous system. Silicon micromachined electrode arrays now permit the long-term monitoring of neural activity in vivo as well as the insertion of electronic signals into neural networks at the cellular level. Efforts to understand and engineer the biology of the implant/tissue interface are also underway. These electrode arrays are facilitating significant advances in our understanding of the nervous system, and merged with on-chip circuitry, signal processing, microfluidics, and wireless interfaces, they are forming the basis for a family of neural prostheses for the possible treatment of disorders such as blindness, deafness, paralysis, severe epilepsy, and Parkinson's disease.

/pdf/wireless-implantable-microsystems-high-density-electronic-2s60s28lz9.pdf

Wireless implantable microsystems: high-density electronic interfaces to the nervous system

The next generation of implantable high-power neuroprosthetic devices such as visual prostheses and brain computer interfaces are going to be powered by transcutaneous inductive power links formed between a pair of printed spiral coils (PSC) that are batch-fabricated using micromachining technology. Optimizing the power efficiency of the wireless link is imperative to minimize the size of the external energy source, heating dissipation in the tissue, and interference with other devices. Previous design methodologies for coils made of 1-D filaments are not comprehensive and accurate enough to consider all geometrical aspects of PSCs with planar 3-D conductors as well as design constraints imposed by implantable device application and fabrication technology. We have outlined the theoretical foundation of optimal power transmission efficiency in an inductive link, and combined it with semi-empirical models to predict parasitic components in PSCs. We have used this foundation to devise an iterative PSC design methodology that starts with a set of realistic design constraints and ends with the optimal PSC pair geometries. We have executed this procedure on two design examples at 1 and 5 MHz achieving power transmission efficiencies of 41.2% and 85.8%, respectively, at 10-mm spacing. All results are verified with simulations using a commercial field solver (HFSS) as well as measurements using PSCs fabricated on printed circuit boards.

Design and Optimization of Printed Spiral Coils for Efficient Transcutaneous Inductive Power Transmission

A simple, physically based analysis illustrate the noise processes in CMOS inverter-based and differential ring oscillators. A time-domain jitter calculation method is used to analyze the effects of white noise, while random VCO modulation most straightforwardly accounts for flicker (1/f) noise. Analysis shows that in differential ring oscillators, white noise in the differential pairs dominates the jitter and phase noise, whereas the phase noise due to flicker noise arises mainly from the tail current control circuit. This is validated by simulation and measurement. Straightforward expressions for period jitter and phase noise enable manual design of a ring oscillator to specifications, and guide the choice between ring and LC oscillator

http://venividiwiki.ee.virginia.edu/mediawiki/images/c/c2/A_abidi.pdf

Phase Noise and Jitter in CMOS Ring Oscillators

Timing jitter sequences Δϕj[n] and Δϕk[n] of respective clock signals under measurement xj(t) and xk(t) are obtained, and a covariance σtj,tk=(1/N)Σi=1NΔϕj[i]•Δϕk[i] is obtained. In addition, root-mean-square values σtj and σtk of the respective Δϕj[n] and Δϕk[n] are obtained, and a cross-correlation coefficient ρ=σtj,tk/( σ tj• σtk) between the xj(t) and xk(t) is calculated.

Apparatus for and method of measuring cross-correlation coefficient between signals

A testing apparatus for testing an electronic device, includes a deterministic jitter applying means for applying deterministic jitter to a given input signal without any amplitude variation component occurring and supplying the input signal applied with the deterministic jitter to the electronic device, a jitter amount controlling means for controlling magnitude of the deterministic jitter to be applied by the deterministic jitter applying means and a judging means for judging quality of the electronic device based on an output signal outputted by the electronic device in response to the input signal.

Testing apparatus and testing method

In this work we present a DFT strategy to test embedded Charge-Pump Phase Locked Loops (CP-PLL) in systems incorporating boundary scan, wherein the proposed DFT allows the verification of the operating frequency range of the CP-PLL while the system is in test mode. This is achieved with a minimal degradation in PLL performance, with lock characteristics remaining unchanged. Simulation results with the layout extracted netlist of the CP-PLL are used to illustrate the working of the technique.

https://ieeexplore.ieee.org/iel3/4814/13308/00606615.pdf

DFT for embedded charge-pump PLL systems incorporating IEEE 1149.1

This paper addresses the problem of diagnosis of flash ADC's and proposes a fault diagnosis technique which employs the Differential NonLinearity (DNL) test data for fault location and identification of the analog components in the converter. In the flash ADC, a fault causes deviation of DNL data from the ideal one. Hence, DNL data can be considered as a functional signature of the ADC. This property is employed for fault diagnosis. DNL patterns are used for fault location, and DNL data are used to calculate the fault values. Both single fault cases and multiple fault cases are considered. The technique proposed here relies only on DNL test data and not on the test method, thus the diagnosis can be carried out using at-operating-speed test data. This paper describes the concept and the detailed diagnosis algorithm. Experiments have been carried out to verify the practicality of the technique. They are presented and discussed in detail. The limitations and practical implementation issues relating to the technique are also addressed.

A fault diagnosis technique for flash ADC's

In this paper, we present methods for constructing optimal tests to detect structural faults in analog integrated circuits in the presence of process variation. The analog test determination problem is formulated as selecting an optimal subset from an initial large set of tests with optimality criteria defined in terms of fault coverage and fault separation on a given fault set. The process variation may be represented either deterministically by box constraints or statistically as random variables. Each of these representations require different methods for computing the detectabilities. In the deterministic case, the detectability measures are computed by a combination of analytical and numerical optimization techniques. Such an approach helps reduce the number of simulations by up to three times over traditional Monte Carlo methods. This approach produces more compact test sets compared to a linear sensitivity analysis while being closer in accuracy to the Monte Carlo method. In the statistical case, the detectability measures are computed as separation distances between the good and faulty distributions. These distributions represented nonparametrically are generated by traditional Monte Carlo techniques. Once the deterministic or statistical detectabilities are computed for the entire test set, a test compaction step is performed which is a covering problem. On solving this covering problem eve get a test set with optimal fault coverage and fault separation.

Mani Soma

Papers

Apparatus for and method of measuring cross-correlation coefficient between signals

Testing apparatus and testing method

DFT for embedded charge-pump PLL systems incorporating IEEE 1149.1

A fault diagnosis technique for flash ADC's

Test set selection for structural faults in analog IC's