Subharmonic Oscillations Induced by Continuous Wave Electromagnetic Interference on a Microwave Phase-Locked Loop

Protecting COVID-19 Vaccine Transportation and Storage from Analog Cybersecurity Threats

Phase locked loops (PLLs) are utilized in SoCs for automotive industry. In the industry, the system handles with satellite signals which are weak radio waves coming from space. Therefore, the output frequency of PLLs is carefully designed to avoid Electromagnetic Interference (EMI). Recently, Global Navigation Satellite System (GNSS) is becoming more common and available frequency bands for clocks are getting narrow (Fig. 1 (a)). That leads, in many products, replacement integer-N PLLs (Int-N PLLs) with fractional-N PLLs (Frac-N PLLs) is needed to obtain smaller output frequency steps than reference frequency. It is important to make Frac-N PLLs as soon as possible to meet a market opportunity. However, it takes long time to make them from scratch. One of answers would be Frac-N digital PLL whose most part is digital circuit which is quickly designed with RTL. However, most of them need time-to-digital converters (TDCs) to make phase quantization noise small [1], [2]. The TDC is a key analog block that requires long time to design and calibration which increases complexity. If we have a fractional divider (FDIV) to make a Frac-N PLL by just connecting to an Int-N PLL, it is useful. Some Frac-N PLLs [3], [4] have been published and they have FDIVs. In [3], extra coarse frequency control is needed to generate the frequency information, increasing complexity. In [4], two-step phase interpolation has been proposed to reduce $\Delta \sum$ quantization noise. However, one of phase interpolators (PIs) is put together with the phase detector. It is tough to apply this structure to ordinary PLLs.

Consider a phase-lock loop (PLL) that is phase locked to a constant frequency reference. Under this condition, the PLL pull-out frequency is defined as the largest input reference frequency step that can be applied without the PLL slipping one or more cycles. The application of an input reference frequency step larger (alternatively, smaller) than the pull-out frequency will (alternatively, will not) cause the loop to break frequency lock and slip one or more cycles. In general, due to the complex nonlinear nature of the dynamics involved, the PLL pull-out frequency can only be approximated. For the second-order PLL containing a proportional-plus-integral loop filter and sinusoidal phase detector, only simulation results have been published, and a formula useful for approximating the pull-out frequency has been curve fitted to these results (an approximation to the pull-out frequency has not been derived analytically). In what follows, an approximation is derived to the pull-out frequency for the above-mentioned PLL. First, with the aid of a phase plane, the pull-out frequency is related to a phase plane separatrix. Next, an asymptotic approximation is developed for this separatrix. This is used in an integral of the nonlinear PLL equation to develop an approximation to the pullout frequency. The analytical results are shown to compare very favorably with numerical simulations.

This work has been focused on designing a phase locked loop (PLL) operating in the GHz range with reduced reference spur and power requirement suitable for wireless communication applications such as wireless receivers, serial link trans-receivers and military communication. A novel PLL is designed using a linear PFD which is free of glitches, dead zone and blind zone, a charge pump based on current splitting technique and a modified current starved differential delay cell (MCSDD) VCO. Performance characteristics of proposed PLL obtained from circuit simulation in Cadence have been compared with simulation results from MATLAB. φ–V characteristics of linear PFD has been found to offer better linearity from −π to π as blind zone and dead zone are eliminated. Glitches at output of PFD have also been eliminated. Charge pump based on current splitting technique in combination with proposed PFD has been found to be effective in reducing leakage current to 3 nA. Tuning range of 98.12% with maximum operating frequency of 4.27 GHz has been obtained for the MCSDD VCO. PLL built with above circuits has been found to offer reference spur of −75.92 dBc@20 MHz offset, phase noise of −113.5 dBc/Hz@100 kHz and lock time of 2.95 μs. It is believed to be the first report of linear PFD in which glitches are completely eliminated. The PLL would be suitable for low power, low noise and high frequency applications as required in mobile communications operating around 20 MHz, to be derived from the VCO when set to generate a frequency of 2.56 GHz.

Design constraints for third-order PLL nodes in master-slave clock distribution networks

A 0.8–3.2 GHz PLL with wide frequency division ratio range

A 29.5 to 31.7 GHz fully integrated phase locked loop (PLL) is presented in this paper. An integrated voltage-controlled oscillator (VCO) and a set of high-speed dividers are used to accomplish all the frequencies. The shunt peaking inductors is added in the first CML divider to higher the operating frequency and lower the power consumption. The current steering charge pump is utilized to improve switching time and thus allow high-speed operation. The PLL can be locked from 29.5 to 31.7 GHz. The PLL including buffers consumes 48mW from 1.2/0.7 V supplies. The output spectrum shows spur suppression higher than 23 dBc. Fabricated in a 65 nm CMOS process, the PLL occupies a chip area of 1.44 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> .

(Kleinman) Associate Professor and Chief of Anesthesiology (Hines), Department of Anesthesiology, Edward Hines Jr. Veterans Administration Hospital, Loyola University Stritch School of Medicine.(Hamilton) Senior Staff Engineer, Telectronics Pacing Systems.(Hariman) Professor of Medicine, Division of Cardiology, Edward Hines Jr. Veterans Administration Hospital, Loyola University Stritch School of Medicine.(Olshansky) Associate Professor of Medicine, Division of Cardiology, Loyola University Stritch School of Medicine.(Justus) Staff nurse anesthetist, Department of Anesthesiology, Edward Hines Jr. Veterans Administration Hospital.(Desai) Staff Anesthesiologist, Department of Anesthesiology, Edward Hines Jr. Veterans Administration Hospital.Received from Edward Hines Jr. Veterans Administration Hospital, Hines, Illinois. Submitted for publication June 24, 1996. Accepted for publication September 11, 1996.Address reprint requests to Dr. Kleinman: Department of Anesthesiology, Loyola University Medical Center, 2160 South First Avenue, Maywood, Illinois 60153.Cardiac pacemaker failure in patients who are pacemaker dependent results in asystole, and can be catastrophic. A major concern is how electromagnetic interference (EMI) from the electrosurgical unit (ESU) will alter pacemaker function. The effects of EMI on pacemaker function are multiple. Electromagnetic interference, by itself, can reprogram some multiprogrammable pacemakers. [1–3]In addition, some pacemakers may automatically convert to the VOO (see Table 1for explanation of pacemaker code) or DOO mode. [4,5]Others may be totally inhibited. [4,5]If total inhibition occurs in a pacemaker-dependent patient, the result will be asystole. Pacemaker inhibition induced by EMI from the ESU generally responds to placement of a precordial magnet on the skin overlying the pacemaker generator. This effectively activates a magnetic reed switch within the pacemaker that converts the pacemaker to a VOO or DOO mode as long as the magnet overlies the generator unit. Atlee [4]recommends having the pacemaker reprogrammed to the VOO mode using a pacemaker programmer. In the VOO mode, the pacemaker is not expected to sense the EMI and, therefore, will continue to pace the heart asynchronously. We report a case of a pacemaker-dependent patient where EMI from the ESU produced total pacemaker inhibition, despite proper placement of a precordial magnet or use of a pacemaker programmer.The patient was a 70-yr-old man scheduled for resection of a carcinoma of the left neck. He had a DDDR pacemaker (Model 1254, Telectronics, Englewood, CO) placed for the treatment of complete heart block 3 yr before his current admission. He was currently pacemaker dependent. The pacemaker generator was placed in the left infraclavicular region and attached to endocardial ventricular (Cordis Core, Miami, FL, model 330–201) and atrial (Telectronics, model 330–801) leads. He had no subsequent problems related to his heart or pacemaker since its insertion. Regular clinic visits showed that his pacemaker was working appropriately and the intended programmed settings, in the DDD mode, were operational.Physical examination revealed an arterial pressure of 150/70 mmHg and a paced heart rate of 70 beats/min.After appropriate monitors were placed, including a cannula in his right radial artery for continuous blood pressure monitoring, anesthesia was induced with thiopental and, after intravenous succinylcholine, the trachea was intubated. The return plate to the unipolar ESU (System 5000, Power Plus, C. R. Bard, Englewood, CO) was placed under the patient's left buttock. Desflurane and nitrous oxide were used to maintain anesthesia. The operative course was unremarkable until neck dissection was begun. Activation of the ESU by the surgeon initiated asystole. After placement of a precordial magnet on the skin over the pacemaker generator by the anesthesiologist, the surgeon proceeded. When the ESU was activated again, the pacemaker was totally inhibited, asystole ensued for almost 6 s, and the arterial pressure trace decreased precipitously. A cardiologist then interrogated and reprogrammed the pacemaker to the VOO mode (Telectronics Pacemaker Programmer model 9600). The surgeons proceeded once again with the surgery. Activation of the ESU continued to result in asystole, duplicating the previous findings. The operation was completed using a bipolar ESU. The pacemaker functioned as expected in the programmed VOO mode for the remainder of the surgery, which proceeded uneventfully.Postoperatively, the pacemaker was interrogated, and found functioning normally. It was then reprogrammed to its previous DDD settings.Use of a precordial magnet to convert a pacemaker to an asynchronous mode (VOO or DOO) should be restricted to instances when EMI can cause life-threatening inhibition of the pacemaker. Routine prophylactic use of the precordial magnet is not recommended because of possible pacemaker reprogramming in the presence of EMI. [4,5]This is particularly true for those pacemakers that use a magnetic reed switch to enable the pacemaker to receive programming instructions. [5]Radiofrequency signals are used for programming instructions after the magnetic reed switch has been enabled. High frequency EMI from the ESU could be misinterpreted as a programming instruction. [5]The new reprogrammed parameters would then become manifest after the magnet is taken off the skin overlying the pacemaker generator. How the pacemaker would be reprogrammed depends on the pacemaker's characteristics and is often unpredictable.With the activation of the ESU, the patient's arterial pressure decreased precipitously. Because the patient was pacemaker dependent, we elected to change the mode of the pacemaker from DDD to VOO, using the precordial magnet. However, this failed to prevent a recurrence of the events when the ESU was once again activated. Failure of a precordial magnet to change a VVI pacemaker to VOO mode in the surgical setting was described previously. [6]However, in that case, failure of the magnet occurred because the pacemaker had inadvertently been left in a noninvasive threshold testing mode, designated as “vario” by the manufacturer, when the patient was seen in the pacemaker clinic before his surgery. In the “vario” mode, application of a precordial magnet will not convert the pacemaker from VVI to VOO. The Telectronics Model 1254 pacemaker present in our patient does not have a “vario” mode. In addition, our patient's pacemaker clinic records clearly documented that the pacemaker was in the appropriate DDD mode, and the problem persisted despite appropriate reprogramming of the pacemaker to the VOO mode by the cardiologist.The events described were not due to technical pacemaker failure, because the pacemaker was subsequently found to be operating within company specifications. This pacemaker, similar to all dual-chambered Telectronics pacemakers, is equipped with a unique, high-voltage protection circuit (Figure 1). This circuit monitors the voltages continuously in the electrodes and the case of the generator itself. High voltages monitored include those induced by the ESU or by defibrillator shocks. Once a high voltage, exceeding manufacturer's threshold, is detected, electronic switches open, effectively disconnecting all electrodes (and the case) from the pacemaker output circuitry. This protects the components of the pacemaker circuitry from these high voltages, which prevents permanent pacemaker damage but also prevents effective output from the pacemaker. In the presence of the EMI from the ESU, the impulses emanating from the pacemaker could not exit and conduct down the pacemaker lead. This led to an apparent and effective pacing failure in the VOO mode even though the pacemaker's output circuitry was in the VOO mode. This can lead to temporary pacemaker failure, as demonstrated by our case.All pacemaker manufacturers use a strategy to prevent or limit retrograde currents from entering the pacemaker. The specific circuitry involved varies from company to company. Most companies use a series of zener diodes to prevent retrograde currents.*,**,***,**** This arrangement will theoretically allow an operational VOO mode even in the presence of EMI. However, it also makes possible, in the presence of very high induced voltages, retrograde currents, and, therefore, possible permanent pacemaker damage. The circuit design depicted in Figure 1can lead to temporary operational failure of the VOO mode in the presence of powerful EMI, as it did in our case, but will prevent possible permanent pacemaker damage. Because of the absence of clinical outcome data, each manufacturer determines which tradeoffs to make and, therefore, which circuit design to incorporate into their devices.A few lessons can be learned from this case. First, in the presence of EMI from a unipolar ESU, a precordial magnet will not effectively convert all pacemakers to a functional VOO mode even when the pacemaker's output circuitry is functioning properly. Second, even reprogramming this type of pacemaker to the VOO mode will not guarantee continuous pacing in the presence of powerful EMI. We recommend that, if the pacemaker output is inhibited by the ESU, and inhibition results in asystole, a precordial magnet should still be tried, because, without knowledge of pacemaker brand and model, it can not be known a priori whether the precordial magnet will work. If the use of the precordial magnet still leads to pacemaker inhibition with ESU activation, the anesthesiologist should consider whether brief periods of asystole might be tolerated, provided there was sufficient time for recovery between periods when the surgeon was not using the ESU. If this approach is not feasible, the position of the return plate should be changed. This, conceivably, could change the voltage vector, leading to a smaller amount of current being conducted retrograde by the pacemaker lead. Another strategy that could be tried is to decrease the power of the ESU. If these maneuvers fail to reverse the inhibition of output of the pacemaker, the anesthesiologist and surgeon should consider completion of the operation by using a bipolar ESU. Afterwards, the pacemaker should be interrogated electronically to ensure proper function and programmed settings.There are two heat-generating surgical scalpels that likely will not interfere with pacemaker function. These devices are now not commonly used. However, anesthesiologists should be aware of them, because they offer possible alternatives to dealing with the problem described in our case. One device is the Shaw Hemostatic Scalpel (Hemostatix Medical Devices, Cherry Hill, NJ). [7]It works by true cautery but is electrically insulated from the patient by a Teflon (E.I. DuPont de Nemours Co., Wilmington, DE) coating. The other is the Ultracision Harmonic Scalpel (Ultracision, Smithfield, RI). [8]This device generates heat for cutting and coagulation by vibrating at a high frequency. The harmonic scalpel, therefore, relies on mechanical, not electrical, energy to cut and coagulate and has been used successfully in a pacemaker-dependent patient. [8]More than 10 yr ago, Shapiro et al., [6]in concluding his article on intraoperative pacemaker failure wrote that “it is impossible to know how every pacemaker functions.” Because of their growing complexity at the time, he called for industry-wide standardization of all aspects of pacemaker technology. In the ensuing 10 yr, pacemaker technology has grown even more complex, and Shapiro's sentiments are as true now as they were then.*Personal communication with Medtronic, May 1996.**Personal communication with CPI, May 1996.***Personal communication with Pacesetter, May 1996.****Personal communication with Intermedics, May 1996.

Underground Electro Magnetic Interference (EMI) has become so serious that there were false alarms in monitoring system, which induced troubles of coal mine safety in production. In order to overcome difficulties caused by the explosion-proof enclosure of the equipments and the limitation of multiple startup and stop in transient process during EMI measurement, a novel technique was proposed to measure underground EMI distri- bution indirectly and enhance Electromagnetic Campatibility(EMC) of the monitoring sys- tem. The wavelet time-frequency analysis was introduced to underground monitoring sys- tem. Therefore, the sources, the startup time, duration and waveform of EMI could be as- certained correctly based on running records of underground electric equipments. The electrical fast transient/burst (EFT/B) was studied to verify the validity of wavelet analysis. EMI filter was improved in accordance of the EMI distribution gotten from wavelet analysis. Power port immunity was developed obviously. In addition, the method of setting wavelet thresholds was amended based upon conventional thresholds in the wavelet filter design. Therefore the EFT/B of data port was restrained markedly with the wavelet filtering. Coor- dinative effect of EMI power and wavelet filter makes false alarms of monitoring system reduce evidently. It is concluded that wavelet analysis and the improved EMI filter have enhanced the EMC of monitoring system obviously.

Phase‐locked loops (PLLs) are critical for synchronizing modular multilevel converter high voltage direct current (MMC‐HVDC) systems with alternating current (AC) grids, yet their stability impacts remain underexplored. This study systematically compares the impacts of the synchronous reference frame‐PLL (SRF‐PLL) and the inertia PLL (IPLL) on small‐signal stability and large‐signal synchronization. A unified framework is adopted to enable unbiased comparison by aligning their bandwidths. A small‐signal model, incorporating PLL dynamics, is developed, based on which PLL impacts are examined using impedance‐based generalized Nyquist criteria. The analysis results show that system stability depends primarily on PLL bandwidth rather than structure. This reveals inherent limitations of PLL‐based synchronization and motivates PLL‐less designs for improving stability. To enhance large‐signal synchronization, a phase correction pathway is introduced for the SRF‐PLL. This approach improves synchronization while avoiding steady‐state phase detection errors inherent to the IPLL. Finally, all results are verified by non‐linear time‐domain electromagnetic transient simulations in PSCAD. This work advances quantitative understanding of PLL characteristics and stability impacts in MMC‐HVDC systems, providing motivation for adopting PLL‐less system designs.

ABSTRACTIn this paper, Tunable Self-Oscillating Switching (TSOS) technique for Dynamic Wireless Charging (DWC) of Electric Vehicle (EV) is investigated. TSOS is a suitable option for DWC, which has parameter variation and requires fast frequency tracking. The system consists of a high-frequency full-bridge inverter, a series–series compensated loosely coupled transformer that is created by Unequal Double D (UDD) coils and a Li-Ion battery as the load that is connected to the output of the full-bridge rectifier. To achieve high efficiency and energy transfer and realise zero voltage switching, the phase of total impedance in steady state condition is investigated. To limit the overshoot of current in the system, a variable phase control method is proposed. Also, an investigation on the proper point to start the charger is performed to decrease the overshoot of current and increase the efficiency. Using this method, overshoot of current could be limited to 50% and energy efficiency could be at least 92.68%. To analyse this method, simulation is done in the Simulink/MATLAB, and to verify the results, a laboratory prototype is implemented.Abbreviations:TSOS: Tunable Self-Oscillating Switching; DWC: Dynamic Wireless Charging; EV: Electric Vehicle; DD: Double D; UDD: Unequal Double D; IPT: Inductive Power Transfer; CT: Current Transformer; MCU: Micro Controller Unit; SOS: Self-Oscillating Switching; ZVZCS: Zero Voltage and Zero Current Switching; EMI: Electromagnetic Interference; SS: Series–Series; PLL: Phase-Locked Loop; DC: Direct Current

This paper proposes a fractional-N dual-feedback phase-locked loop (DFPLL) architecture featuring a Class-Cdriven FBAR oscillator and harmonic mixer(HM)-based topology with nested phase-locked loops(nested PLL). The nested PLL serves as an anti-aliasing filter, enhancing the operating frequency of the delta-sigma modulator (DSM) and effectively suppressing quantization noise. The HM path, utilizing a low-noise, highfrequency FBAR reference, resolves stability issues inherent in the nested PLL structure and mitigates noise retro-injection to minimize reference noise gain. A ring-type VCO topology provides significant area reduction and enhanced robustness against electromagnetic interference. Designed in TSMC 65 nm CMOS technology with a 1.2 V supply voltage and occupying $0.394 \mathrm{~mm}^{2}$ layout area, when operating at 3.72 GHz output frequency, the circuit achieves 12.32 mW power dissipation with $-\mathbf{7 0. 4} d B c$ reference spurs and $\mathbf{3 5 5} f s$ integrated jitter.

The increasing interconnection of inverter-based resources (IBRs) with low short-circuit current has weakened grid strength, making phase-locked loops (PLLs) susceptible to instability due to accumulated phase-angle error under current limiting. This study defines such instability as IBR instability induced by reduced grid robustness and proposes a root-mean-square (RMS) model-based screening method. After fault clearance, the residual q-axis voltage observed by the PLL is treated as a disturbance signal and, using the PLL synchronization equations, is analyzed with a standard second-order formulation. The maximum phase angle at which synchronization fails is defined as θpeak, and the corresponding q-axis voltage is defined as Vq,crit. This value is then mapped to a screening metric Ppeak suitable for RMS-domain assessment. The proposed methodology is applied to the IEEE 39-bus test system: the stability boundary and Ppeak are obtained in Power System Simulator for Engineering (PSSE), and the results are validated through electromagnetic transient (EMT) simulations in PSCAD. The findings demonstrate that the RMS-based screening can effectively identify operating conditions that are prone to PLL instability in weak grids, providing a practical tool for planning and operation with high IBR penetration. This screening method supports power system planning for high-penetration inverter-based resources by identifying weak-grid locations that require EMT studies to ensure secure operation after grid faults.

The electromagnetic compatibility (EMC) analysis of electromagnetic interference (EMI) filter circuits using 3-D numerical modeling by the partial element equivalent circuit (PEEC) method represents the central topic of this paper. The PEEC-based modeling method is introduced as a useful tool for the prediction of the high frequency performance of EMI input filters, which is affected by PCB component placement and self- and mutual-parasitic effects. Since the measuring of all these effects is rather difficult and time consuming, the modeling and simulation approach represents a valuable design aid before building the final hardware prototypes. The parasitic cancellation techniques proposed in the literature are modeled by the developed PEEC-boundary integral method (PEEC-BIM) and then verified by the transfer function and impedance measurements of the L-C and C-L-C filter circuits. Good agreement between the PEEC-BIM simulation and the measurements is achieved in a wide frequency range. The PEEC-BIM method is implemented in an EMC simulation tool GeckoEMC. The main task of the presented research is the exploration of building an EMC modeling environment for virtual prototyping of EMI input filters and power converter systems.

We present DAGSENS, a new theory for parametric transient sensitivity analysis of Differential Algebraic Equation systems (DAEs), such as SPICE-level circuits. The key ideas behind DAGSENS are, (1) to represent the entire sequence of computations, starting from DAE parameters, all the way up to the objective function whose sensitivity is needed, as a Directed Acyclic Graph (DAG) called the "sensitivity DAG", and (2) to compute the required sensitivities efficiently (with time complexity linear in the size of the sensitivity DAG) by leveraging dynamic programming techniques to traverse the DAG. DAGSENS is simple, elegant, and easy-to-understand compared to existing sensitivity analysis approaches; for example, in DAGSENS, one can switch between direct and adjoint transient sensitivities just by changing the direction of DAG traversal (i.e., topological order vs. reverse topological order). Also, DAGSENS is significantly more powerful than existing sensitivity analysis approaches because it allows one to compute the sensitivities of a much more general class of objective functions, including those defined based on "events" that occur during a transient simulation (e.g., a node voltage crossing a particular threshold, a phase-locked loop (PLL) achieving lock, a signal reaching its maximum/minimum value during a transient run, etc.). In this paper, we apply DAGSENS to compute the sensitivities of important event-driven performance metrics in several real-world electronic and biological applications, including high-speed communication (featuring sub-systems such as I/0 links and PLLs), statistical cell library characterization, and gene expression in Drosophila embryos.