Pulse-width modulation

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Topic: Pulse-width modulation

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	Pulse-width modulation - Wikipedia, the free encyclopedia
		The pulse center may be fixed in the center of the time window and both edges of the pulse moved to compress or expand the width.
		Because the duty cycle of the modulation is the same as the AC frequency of the line (50 Hz or 60 Hz in most countries) and PWM dimmers are often used with incandescent lamps, the human eye sees only the average intensity (see flicker fusion).
		The discrete on/off states of the modulation are used to control the state of the switch(es) which corespondingly control the voltage across or current through the load.
	en.wikipedia.org /wiki/Pulse-width_modulation (872 words)

	Modulation - Wikipedia, the free encyclopedia
		A device that performs modulation is known as a modulator and a device that performs the inverse operation of demodulation is known as a demodulator.
		Modulation is the process of varying a carrier signal in order to use that signal to convey information.
		In digital modulation, the changes in the signal are chosen from a fixed list (the modulation alphabet) each entry of which conveys a different possible piece of information (a symbol).
	en.wikipedia.org /wiki/Modulation (731 words)

	Pulse-position modulation - Wikipedia, the free encyclopedia
		One of the principle advantages of Pulse Position Modulation is that it is an M-ary modulation technique that can be implemented non-coherently, such that the receiver does not need to use a Phase-locked loop (PLL) to track the phase of the carrier.
		Pulse position modulation is also used for communication to the ISO 15693 contactless Smart card.
		Pulse-position modulation is a form of signal modulation in which M message bits are encoded by transmitting a single pulse in one of 2
	en.wikipedia.org /wiki/Pulse-position_modulation (724 words)

	30162.020411&ELEMENT_SET=DECL
		Pulse width modulation module 92 is configured to generate a pulse signal corresponding to the waveform signal provided by generator 94.
		The output port of pulse width modulation module 92 is coupled to gate driver circuit 90.
		The pulse width modulated signal generator provides a pulse width modulated signal that is derived from a lamp drive voltage waveform having the desired characteristics as required for eliminating color segregation in the lamp.
	www.wipo.int /cgi-pct/guest/getbykey5?KEY=02/30162.020411&ELEMENT_SET=DECL (4510 words)

	pdm_article_solid_state
		In this discussion, the modulator uses Pulse Width Modulation internally, however, the pulses are removed and the output converted to modulated, standard audio-modulated DC before application to the modulated RF stage.
		If you want your pulse width modulator to be able to modulate your transmitter up to 99% negative, without distortion, then the pulse modulator/amplifier should be capable of passing a pulse which is 1/100th of the total period of the switching waveform.
		The pulse waveform is set up so that, at carrier (no modulation) the modulator device is on for 40% of the total time, and off for 60% of the total time.
	www.netway.com /~stevec/ham/pdm_article_solid_state.html (5277 words)

	O'Reilly Network -- Introduction to Pulse Width Modulation (PWM)
		Pulse width modulation (PWM) is a powerful technique for controlling analog circuits with a processor's digital outputs.
		The duty cycle is the ratio of the on-time to the period; the modulating frequency is the inverse of the period.
		PWM is employed in a wide variety of applications, ranging from measurement and communications to power control and conversion.
	www.oreillynet.com /pub/a/network/synd/2003/07/02/pwm.html (1439 words)

	Pulse Width Modulation (PWM) Basics
		For a single low frequency sine wave as modulating signal modulating the width of a fixed frequency (fs) pulse train the spectra is as shown in Fig 2.
		Regular sampled PWM makes the width of the pulse proportional to the value of the modulating signal at the beginning of the carrier period.
		For three phase systems the modulation of a Voltage Source Inverter can generate a PWM signal for each phase leg by comparison of the desired output voltage waveform for each phase with the same sawtooth.
	www.powerdesigners.com /InfoWeb/design_center/articles/PWM/pwm.shtm (636 words)

	Advanced Data Acquisition Series – Pulse Width Modulation in NI LabVIEW Using NI-DAQmx - Tutorial - Development Library - National Instruments
		Pulse width modulation (PWM) is a technique in which a series of digital pulses is used to control an analog circuit.
		The ratio of the pulse width to the period is referred to as the duty cycle of the signal.
		PWM signals can be generated as a digital signal, using counters or digital output line(s), or as an analog signal, using for instance, an arbitrary waveform generator or an RF signal generator.
	zone.ni.com /devzone/conceptd.nsf/webmain/90DFE241E571056C86256FA4004ABB63?opendocument (956 words)

	49713.000824&ELEMENT_SET=DECL
		One modulation technique is pulse width modulation (PWM) in which a value of an input sample is used to modulate the duration of pulses in an output signal.
		3 is a circuit diagram of one embodiment of a digital pulse width modulation circuit according to the invention.
		A pulse width, or pulse duration, defines a part of what is known as a duty cycle, which is a ratio of a pulse's duration in proportion to the total period.
	www.wipo.int /cgi-pct/guest/getbykey5?KEY=00/49713.000824&ELEMENT_SET=DECL (1999 words)

	PWM - Pulse Width Modulation
		Pulse Width Modulation is a technical method to control the output of an electrical consumer like a DC-motor or a heating element.
		If the pulse width equals the period length the motor is never turned of.
		Control the motor's power output by pulse widths between 0 and period length.
	www.computers-n-robots.de /pwm.html (372 words)

	Theory for Pulse Width Modulation Type DC to AC High Efficiency Inverter
		This invention relates to a kind of Pulse Width Modulation Type DC to AC High Efficiency Inverter, specially concerns the one that incorporating with a storage battery 12V or 24V.
		The pulse transformer's secondary in the unit of the boosting switch circuit 2 outputs a square pulse that of which the frequency is 50KHz?100KHz, the On-Off ratio of the width is 0~90%.
		The pulse width modulating circuit 6 outputs a pulse from ports E1 and E2 to 17 and 123 to control the boosting driving circuit 5.
	www.chinadepot.com /invertchow2.html (1656 words)

	Lab Assignment #6 - Pulse Width Modulation
		While the timer module can be used for pulse width modulation, the PWM module is more flexible and easier to use.
		The HS12 has an 8 channel Pulse Width Modulation module which is separate from the timer module.
		The period of the signal is 20mS, and the pulse width varies from 1.25mS to 1.75mS to control the servo position with 1.5mSec placing the servo at its midpoint.
	www.almy.us /classes/eet327/lab6.html (781 words)

	Measuring Pulse-Width-Modulation Signals with CompactRIO - Tutorial - Development Library - National Instruments
		Each pulse width measurement takes the form of a counter on a shift register which is incremented every iteration of the loop for which the associated input bit is high.
		Each pulse varies from 1.0 to 2.0 milliseconds, with approximately 1.5 ms corresponding to a centered joystick, and larger or smaller pulses corresponding to joystick positions away from center.
		PWM decoding is performed in the reconfigurable FPGA logic and then the data is passed to the embedded real-time processor.
	zone.ni.com /devzone/conceptd.nsf/webmain/56E266D02339921B86256EE4007354B2 (1031 words)

	PIC16C84 - Pulse Width Modulation
		Pulse Width Modulation is a technique to provide an output logic one for a period of time and a logic for the balance of the time.
		In routine, PWM, the W register is used as the accumulator.
		Note that in this application, it is important that when the output is not being modulated with a precise duty cycle that the ouput be placed in a high impedance mode so as to avoid charging or discharging the capacitor.
	www.phanderson.com /PIC/16C84/pwm.html (730 words)

	Lee presents App. Note: Valve Flow Control Using Pulse Width Modulation
		Pulse width modulation (PWM) can be used to control average flow by varying the valve duty cycle on some (usually) fixed base frequency to match the flow requirement.
		Using pulse width modulation, a bi-stable solenoid valve can be used to very effectively control flow over a range exceeding 10:1.
		The graph above shows a typical pulse width sequence for a valve that is decreasing normally open port flow over time, as in the graph below.
	www.theleeco.com /EFSWEB2.NSF/1c6397740f8b45e1852563b9006d6bc6/893720ad39a7fc18852564bc006f7f2e!OpenDocument (324 words)

	Pulse Width Modulation
		You can use the example code as is and adjust R7 to control the Pulse Width without going through the rest of the detailed explanation of how the code works.
		This example uses one of the microcontrollers built in timers to control the pulse width.
		Register R7 is used to control the pulse width.
	www.iguanalabs.com /pwm.htm (2137 words)

	Explain pulse width modulation - MP3Car.com Forums
		look up 555 and pulse width modulation, should be cheap..
		PWM is great if you have a microcontroller drivin it but it isn't the only way to drive a motor slower.
		Usually there is a capacitor between the outputs of the PWM circuitry to even out the spikes and drops a little bit.
	www.mp3car.com /vbulletin/showthread.php?t=38232 (850 words)

	Pulse Width Modulation
		By adjusting the duty cycle of the signal (modulating the width of the pulse, hence the 'PWM') ie, the time fraction it is "on", the average power can be varied, and hence the motor speed.
		A different approach is adopted in a PWM controller from Nomad using little more than a 555 and a PNP switching transistor.
		I don't see the problem with low-power fans as a detriment, PWM control is most appropriate for more powerful fans that produce a lot of waste heat with linear control.
	www.cpemma.co.uk /pwm.html (2006 words)

	PIC Microcontoller IO Routines for Pulse Width Modulation
		The output pulse will range from 10 microseconds corresponding to 1 V to 1 microsecond corresponding to 10 V. The circuit will be descrete and has two inputs.
		Pulse Code Modulator Hi, I need to do my project call " Pulse Code Modulator " To design the following: 1.
		The frequency you run that timer at is a function of both the pwm frequency and the resolution you need.
	www.sxlist.com /techref/microchip/pwm.htm (1296 words)

	TechOnLine - Using a Function Generator to Create Pulse-Width Modulation (PWM) Waveforms
		Pulse width modulation offers a simple method for digital control logic to create an analog equivalence.
		The use of pulse-width modulation (PWM) continues to increase with the rise in digital control logic.
		Using a Function Generator to Create Pulse-Width Modulation (PWM) Waveforms
	www.techonline.com /community/ed_resource/38357 (107 words)

	Why PWM?
		Pulse Width Modulation (PWM) is the most effective means to achieve constant voltage battery charging by switching the solar system controller’s power devices.
		When a battery voltage reaches the regulation setpoint, the PWM algorithm slowly reduces the charging current to avoid heating and gassing of the battery, yet the charging continues to return the maximum amount of energy to the battery in the shortest time.
		PWM has recently surfaced as the first significant advance in solar battery charging.
	www.morningstarcorp.com /support/Why-PWM/why-pwm-1.shtml (538 words)

	PWM -- Pulse Width Modulation
		Pulse Width Modulation refers to a method of carrying information on a train of pulses, the information being encoded it the width of the pulses.
		The PWM scheme releases servo amps from this great disadvantage, at the cost of slightly greater complexity.
		A good output filter should be provided to reduce current fluctuations through the PWM cycle, and also to reduce electromagnetic interference.
	www.timgoldstein.com /cad_cam/pwm.htm (355 words)

	Pulse Width Modulation For Power Converters: Principles And Practice, Holmes - ISBN 0471208140 - ELX.com.au (Australia)
		Pulse Width Modulation for Power Converters: Principles and Practice is the first single-volume resource written to help researchers in the field attain a working knowledge of the subject.
		Pulse Width Modulation for Power Converters: Principles and Practice enables the reader to achieve optimum PWM results for any application.
		The selection of the best algorithm for optimum pulse width modulation is an important process that can result in improved converter efficiency, better load (motor) efficiency, and reduced electromagnetic interference.
	www.elx.com.au /item/0471208140 (348 words)

	pulsewdith.circuit.txt
		----- --- - Inputs "PWM1" and "PWM2" are the pulse width modulation inputs.
		As shown the values are chosen for plus and minus 15 volt supplies, with the pulse width control voltage range matching the amplitude of the input waveform.
		The values of the 91K input resistors to this pulse width control voltage summing amplifier (IC-1) can be adjusted up or down to suit individual requirements.
	machines.hyperreal.org /categories/do-it-yourself/schematics/pulsewdith.circuit.txt (870 words)

	4QD-TEC: PWM speed control
		The circuit uses a 3524, a 'regulating pulse width modulator' so a brief description of the IC seems to be in order.
		The PWM output signal from the 3524 is fed to a pair of emitter followers to give adequate gate drive.
		Connected thus the output is a regular pwm output (as described at the top of this page) with a fixed frequency and an on time variable from 0% to 90%.
	www.4qdtec.com /pwm-01.html (4704 words)

	Infra Red Explained - Remotes Homepage
		In Pulse Width Modulation the duration of the ON (carrier present, light flashing thousands of times per second), or Off (no light at all coming out of the IR emitter) periods is made to vary.
		It is a pulse width modulation system where the information is carried in the length of the off time with a fixed duration of on time.
		An example of this might be the resetting of all convergence offsets, or altering the width or height of the picture.
	www.hifi-remote.com /infrared/IR-PWM.shtml (3313 words)

	What is 'Pulse Width Modulation'???
		This picture and the next few will demonstrate how we will be using 'Pulse Width Modulation' to vary the speed of our motors in both forward and reverse.
		The multimeter is indicating the pulse frequency of the circuit.
		Here, the thumbwheel is 'off', and both forward and reverse lines are off.
	www.prismnet.com /~jrf/SubPics/image517.html (92 words)

	Waveform Generator offers pulse width modulation., Agilent Technologies, Inc.
		The ability to generate variable edge-time pulses up to 5 MHz, with selectable period, pulse width and amplitude, makes the Agilent 33220A ideally suited to a wide variety of electronic applications requiring flexible pulse signals.
		The Agilent 33220A, priced at less than $1,900, is the first 20 MHz function/arbitrary waveform generator in its price range to combine variable edge pulse and PWM functionality with a 50 MSa/s, 14 bit, 64K-point arbitrary waveform capability.
		The combination of the new pulse function with the Agilent 33220A's 50 MSa/s, 14 bit, 64K-point arbitrary waveform capability provides engineers in the electronics, automotive, aerospace, government, medical and computer industries with unmatched performance for the design, verification, and test of electronic components, sub-assemblies and end products.
	news.thomasnet.com /fullstory/18996 (1076 words)

	Pulse Width Modulation
		Therefore, we regulate the speed by using a technique called Pulse Width Modulation (PWM).
		Basically, its a high frequency pulse sent to our device.
		The device isn't able to respond to the high freqency and kind of "blends" through.
	www.sfu.ca /~gswamina/2004.03.06.html (472 words)

	Pulse Width Modulation 2
		As the potentiometer is turned up, the charge (On) time increases, discharge (Off) time decreases, so the PWM duty cycle increases until the On time is around 100x the Off time for the maximum duty cycle.
		With the 100nF timing capacitor C1, PWM frequency is about 100Hz, the right spot for DC motors.
		This controller is aimed at speed control of small motors or for dimming low-voltage lighting, where the kick-start feature of Nomad's controller isn't wanted.
	www.cpemma.co.uk /555pwm.html (829 words)

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Topic: Pulse-width modulation

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