Algorithm Evaluates Complex Fraction  08/03/95 EDNDesign Ideas The following algorithm uses rectangulartopolar conversion to evaluate a complex fraction (one that includes imaginary numbers]. The algorithm is most convenient when you can perform rectangulartopolarcoordinate and polartorectangularcoordinate conversions using a calculator such an HP 11C. You can reduce all necessary Design by Paul Johnson, HewlettPackard, Escondido, CA
Algorithm Extracts Cube Root  01/15/98 EDNDesign Ideas The C routine in Listing 1 generates the cube root of either a positive or a negative number. The number can range from a small fraction to greater than 1 billion. Note that this idea is irrelevant for a PC, which includes a math library with the compiler and produces a more accurate result with less effort. However, this idea is useful if you use a processor for which you don't have a math library. Design by JOHN T HANNON JR, PHILIPS CONSUMER ELECTRONICS CORP, KNOXVILLE, TN
Algorithm extracts roots of Decimal numbers  04/29/99 EDNDesign Ideas NOTE
: Scroll to find this one. "Algorithm extracts cube root" (EDN, Jan 15, 1998, pg 100) covers only the onethird power (cube root). In contrast, the C routine in Listing 1 calculates the Kth root (X1/K) of positive decimal numbers X. Both K and X can vary widely. You type in X, K, and an estimate of the root; the routine then calls the calcRoot function in the software program. Design by Frank Vitaljic, Bellingham, WA
Algorithm Generates Random Signal  12/05/96 EDNDesign Ideas A common way to simulate a sequence of bandwidthlimitednoise samples is to start with a sequence of uncorrelated random numbers that have a suitable distribution and then pass that sequence through a filter. Unfortunately, filtering affects the signal level, and the complexity of the filter makes computations inefficient. Alternatively, the VHDL algorithm in Listing 1 requires very little computation, Design by Ove Johansson, CelsiusTech Systems, Stockholm, Sweden
Algorithm Keeps Data Safe  21Jan10 EDNDesign Ideas Prevent data loss against power blackouts and other interruptions Design by Luis G Uribe C, Caracas, Venezuela
Algorithm nulls DC offsets in DSP  09/15/94 EDNDesign Ideas One problem associated with converting analog signals to digital samples is ensuring that the zero level of an analog signal (minus its dc offset, if any) converts to a digital sample of exactly zero. If the analog signal's zero level does not convert exactly, the converted samples retain a residual dc component, complicating processing. Design by V Solovyov, Rossiya, Russia
Algorithm tests for point location  08/03/00 EDNDesign Ideas A recent software project approximated the phasespace trajectory (also known as a strange attractor) of a certain dynamic system by using several nonoverlapping triangles. It became necessary to determine whether particular opera Design by Lawrence Arendt, Manitoba HVDC Research Centre, Winnipeg, Canada
Algorithm Transforms Filter Coefficients  01/21/99 EDNDesign Ideas To synsize infiniteimpulseresponse (IIR]filter functions, expressed as H (z], you commonly use analog prototypefilter functions, expressed as H (s], using bilinearz transform. This operation entails some algebraic complexity in calculating filter coefficients. The simple algorithm shown here transforms prototypefilter coefficients (W0, W1, W2]to IIR digitalfilter coefficients (U0, U1, U2]. These coefficients transform from Design by Frank Vitaljic, Bellingham, WA
Algorithm Yields Precise Bessel Function  11/09/95 EDNDesign Ideas You frequently need to determine the Bessel function of the first kind, Jn (x), for the analysis of modulated and complex waveforms. Such analyses could include, for example, routine verification of transmitter phase or frequencymodulation indices, by the measurement of the signalsuppression terms relative to an unmodulatedcarrier reference level. Another example is the evaluation of communicationchannel performance through sophisticated computer simulations Design by Brian Geelen, Satellite Microwave & Communications Ltd Weert, The Netherlands
Amplifier for a Xenon Lamp Flash Detector  This circuit has a very low standby current requirement yet has very high sensitivity toward the light flashes from a xenon lamp. When connected to a flip/flop it can serve as an on on/off Controller. . . Circuit by David Johnson P.E.February, 2002
Basic logarithmic Amplifier using opamp & NPN transistor  Schematic only
Battery Charge Current Indicator  This circuit turns on a LED whenever it detects at least 25ma of battery charge current. . . Circuit by David Johnson P.E.July, 2006
Bodmas Rule  The term ‘BODMAS’ is an acronym for ‘bracket,’ ‘of’, ‘division,’ ‘multiplication,’ ‘addition’ and ‘subtraction’ and the ‘BODMAS rule’ is a mnemonic for the hierarchy of various arithmetical operators. A mathematical expression __ Electronics Projects for You
Circuit indicates Battery Charging Current  Anyone who has ever had a shocking experience on an especially dry day is acutely aware of the kinds of high voltage that can be generated from a simple walk across a carpeted floor. Those same finger to metal sparks can destroy or disrupt sensitive elect . . . Hobby Circuit designed by David A. Johnson P.E.January, 2011
Circular slide rule provides quick results  EDNDesign Ideas March 26, 1998 [ NOTE
: File has multiple design, scroll for this one.] In analogcircuit design, most calculations you make need not be very precise. If you need an LEDcurrent calculation or a couplingcapacitor value, for example, ±5% or even ±10% accuracy is usually adequate. It's sometimes inconvenient to make these calculations with a pocket calculator. For example, finding the cutoff frequency of a 3.3kiloohms/47pF network requires approximately 20 key presses. Design by Jacek Pawlowski, PW INMEL, Zielona Góra, Poland
DC Current Indicator #4  The circuit below uses some common components to turn on an LED whenever DC current above a certain level is detected. The circuit uses a very popular LM393 dual voltage comparator from National Semiconductor and a common 1N4148 signal diode. The diode. . . Circuit by Dave Johnson P.E.October, 2005
DC Current Indicator 6  The circuit below is a simple way to indicate when DC current is flowing through a wire. The circuit is designed so it will turn on a LED indicator light, whenever the voltage drop across a shunt resistor exceeds about 0.1volts. The value of the resist. . . Circuit by David A. Johnson P.E.October, 2005
Designing an EightBit Arithmetic Logic Unit using Modelsim  This project describes the designing of an 8bit arithmetic logic unit (ALU) using Verilog programming language. It includes writing, compiling and simulating Verilog code in ModelSim on a Windows platform. In digital __ Electronics Projects for You
Detect Short Xenon Lamp Flashes  This circuit uses a small 2.5mm square photo diode in conjunction with a 100mH coil to detect the short light flashes from a xenon lamp. The coil makes the circuit immune to normal room lights. Its 10mv sensitivity can detect light flashes from a range of over 100 feet. . . . Hobby Circuit designed by Dave Johnson P.E.February, 2002
DSP Algorithm Measures Frequency & Damping  10/08/98 EDNDesign Ideas The timedomain DSP algorithm described here allows you to measure the key parameters—natural frequency and damping—in linear, secondorder electromechanical systems. The method applies to a range of electromechanical transducers(electromagnetic or electrostatic], including dynamic speakers, seismic geophones, micromachined sensors, and other systemsContains several designs, scroll to find this one. Design by Olga Belousova, Los Alamos, NM, and Alexander Belousov, New York, NY
Efficient Algorithm Generates Random Signal  12/05/96 EDNDesign Ideas A common way to simulate a sequence of bandwidthlimitednoise samples is to start with a sequence of uncorrelated random numbers that have a suitable distribution and then pass that sequence through a filter. Unfortunately, filtering affects the signal level, and the complexity of the filter makes computations inefficient. Alternatively, the VHDL algorithm in Listing 1 requires very little computation, Design by Ove Johansson, CelsiusTech Systems, Stockholm, Sweden
Fast algorithm computes histograms  10/28/99 EDNDesign Ideas A histogram is a convenient method of presenting statistical features of data; you can use a histogram for an estimate of the probability density function of a random phenomenon. To prepare a histogram entails dividing the interval occupied by data values Design by Lukasz Sliwczynski
General Purpose Arithmetic Block  This is the circuit for the general purpose arithmatic function, an Analog Computer block which solves the equation VO = (V1V2 + V3) ((RF + RG) /RG) in real time. No A/D conversions or software needed! __ Linear Technology/Analog Devices App Note, Jul 2, 2012
Genetic algorithms: programs that boggle the mind  EDN Design Ideas03/03/1997 Assume that you construct a simple device consisting of a power source and two potentiometers in series with an incandescentlight bulb (Figure 1). Assume also that you can rotate the potentiometers 180°, from 90° to +90°, and that the point of least resistance for each potentiometer is in its center (upright) position. Suppose you set the potentiometers to random positions, then you proffer the device to friends and ask them to play with itusing the potentiometers, not the supply voltageto make the light as bright as possible. Most people select one potentiometer, turn it a little to the left or right, and note the result. Design by Clive "Max" Maxfield, Intergraph Computer Systems
