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dpdobrev

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Consultant

Dr. Dobromir Dobrev has about 20 years experience in CMOS and BJT analog and mixed-signal IC design (opamps, comparators, bandgaps, ldos, filters, oscillators, lvdss, plls, adcs, etc.), as well as in signal processing in medical electronics (bioinstrumentation, bioamplifiers, biosignal filtering) where he has many publications. He started working at the Central Laboratory for Electromedical Instrumentation (CLEMA) in a former Medical Academy Sofia. He received his PhD degree in Electronics from the Center of Biomedical Engineering at the Bulgarian Academy of Sciences in 2001. Since 1997 he continued his career mainly in the field of microelectronics. He was an analog IC designer at Semcotec Engineering, Silway Semiconductors, Megaxess and a senior IC designer at Melexis. Currently, he is with FACET (Fabless Center for Engineering and Test), and lives in Sofia, Bulgaria. You can e-mail him at dpdobrev@gmail.com.


dpdobrev

's contributions
  • 08.20.2015
  • Software PLL syncs to line using moving-average filter
  • Multiplying two sinusoids at the mixer output gives: Asin(wt+phi)*Bsin(wt)=0.5AB(cos(phi)+cos(2wt+phi)) cos(2wt+phi) is filtered, thus the mixer output is proportional to cos(phi). cos(phi)=0 for phi=pi/2, thus in locked state the generated frequency has a phase difference pi/2 to the input frequency.
  • 05.14.2015
  • Simulate digital filters with PSpice
  • PSpice becomes popular with Microsim products Design Center and Design Lab. 20 years ago Microsim did revolution with these products. For example, Design Lab 8.0 supports advanced deep-submicron MOSFET models BSIM3V3 (Level 7), which now are still on the edge. Unfortunately, to kill the competition, Microsim was purchased by Orcad, after that Orcad by Cadence, and the PSpice development almost died at the level created by Microsim. Cadence discontinued development of Microsim schematic, but continuous to offer it as separate free software, which can be installed additionally and used. For the users, Orcad PSpice 9.2 becomes the most popular version, from one side because it includes Microsim schematic in the installation package and from another due to the fact that there are almost no difference between 9.2 and the newest versions 16.0 and 16.6.
  • 05.14.2015
  • Simulate digital filters with PSpice
  • Denis, The best tool is this which is simple and easy to use, and of course gives accurate result. For simplicity in use, PSpice (with Microsim schematic, not Orcad!) is irreplaceable, and for AC analysis it is the best, because any AC parameters (amplitude, phase, etc.) can be observed easily with markers. But, in transient analysis with Laplace VCVSs, PSpice sometimes gives not enough accurate result, and the problem is principled and is in the way of calculations done by PSpice in comparison to programs for discrete time simulations. To make more accurate transient simulation, the relative accuracy can be increased, but this drastically increases also the simulation time. So, to observe proper transient behavior of a given z-domain transfer function at a given sampling rate, it should be simulated also (as you say) in e. g. Matlab.