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Topic: Frequency response

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	Frequency response - Wikipedia, the free encyclopedia
		Frequency response is the measure of any system's response at the output to a signal of varying frequency (but constant amplitude) at its input.
		Once a frequency response has been measured (e.g., as an impulse response), providing the system is linear and time-invariant, its characteristic can be approximated with arbitrary accuracy by a digital filter.
		Frequency responses curves are often used to indicate the accuracy of amplifiers and speakers for reproducing audio.
	www.wikipedia.org /wiki/Frequency_response (261 words)

	Frequency Response (Site not responding. Last check: 2007-11-06)
		With a frequency response of 35 Hz to 200 Hz Â±3 dB (anechoic) and a typical in-room response of 20 Hz to 200 Hz (for a 3,000 cubic foot room), the Universal...
		Frequency response is the measure of any system's response to frequency, but is usually used in connection with electronic amplifiers and similar systems, particularly in relation to audio signals.
		For example, a high fidelity amplifier may be said to have a frequency response of 20Hz - 20,000Hz ±1dB, which tells you that the system responds equally to all frequencies within that range and within the limits quoted.
	frequency-response.wikiverse.org (270 words)

	Frequency Response
		A microphone's frequency response pattern is shown using a chart like the one below and referred to as a frequency response curve.
		An ideal "flat" frequency response means that the microphone is equally sensitive to all frequencies.
		For example, a response pattern designed to emphasise the frequencies in a human voice would be well suited to picking up speech in an environment with lots of low-frequency background noise.
	www.mediacollege.com /audio/microphones/frequency-response.html (461 words)

	CTM: Frequency Response Tutorial
		The frequency response is a representation of the system's response to sinusoidal inputs at varying frequencies.
		The frequency response is defined as the magnitude and phase differences between the input and output sinusoids.
		The frequency is on a logarithmic scale, the phase is given in degrees, and the magnitude is given as the gain in decibels.
	www.engin.umich.edu /group/ctm/freq/freq.html (2446 words)

	Frequency response - Wikipedia, the free encyclopedia
		The frequency response of a system can be measured by:
		Similarly, if a system is demonstrated to have a poor frequency response, a digital or analog filter can be applied to the signals prior to their reproduction to compensate for these deficiencies.
		This means that the system amplifies all frequencies within that range within the limits quoted.
	en.wikipedia.org /wiki/Frequency_response (261 words)

	Audio Allies Definition for: Frequency Response
		Frequency response should theoretically be flat when tested with a test signal, however, most speakers and other audio components (but speakers in particular) exhibit dips and peaks in the signal varying to some degree from a perfect, flat response.
		Given that frequency response does vary from a flat line, it is normally quoted as within some range described in decibels (normally 3 dB).
		This simply means that the speaker's frequency response remains within 3 decibels positive or negative of a flat 0 decibel line (a perfectly flat frequency response).
	www.audioallies.com /GetFeatureDesc.asp?Feature=Frequency+Response (421 words)

	Frequency Response Notes (Site not responding. Last check: 2007-11-06)
		Linear electronic circuits can be characterized by their "frequency response" which is a plot of the gain response (and a separate plot of the phase response) of the circuit as a function of frequency.
		is the frequency corresponding to the sum of all of the pole frequencies.
		In the case of the lower cutoff frequency, this means that at the cutoff frequency one of the external capacitors is behaving like a capacitor but the operating frequency is sufficiently high that all of the other external capacitors are behaving like short circuits.
	web.uccs.edu /wbahn/ECE3220/frequencyresponse.htm (5463 words)

	Why Do Frequency Response Curves Matter?
		The issues involved in going from a frequency response curve to the subjective "sound" of a particular loudspeaker or microphone are far too complex to reduce to any fairly simple measurement like a frequency response curve.
		The minimum set of curves needed to characterize a microphone's variation in frequency response and level at different angles is on-axis, 90 degrees (directly to one side), and 180 degrees (directly to the rear).
		At the highest frequencies the pickup angle with respect to the front of the microphone has narrowed, and as a result the frequency response at 90 degrees rolls off at the highest frequencies.
	www.superlux.us /frequency_response.html (2795 words)

	Newtons4th Ltd UK: Frequency Response Analysers
		Frequency response analysers (also known as gain/phase analysers or transfer function analysers) measure the relative gain and phase difference between two points in a circuit.
		Frequency response analysers are particularly important in determining the loop stability of any closed loop feedback system (eg.
		Both frequency response analysers offer other measurement capability as well as frequency response.
	www.frequency-response-analysers.com (226 words)

	Frequency Response of First-Order Lag
		(The is equivalent to the frequency f = w/2pi expressed in cycles per second, also known as Hertz.) We surmise a steady-state solution of the form y(t) = kA sin(wt - q) where k is the amplitude gain factor, and q is the phase shift between the input and output signals.
		Typically we disregard negative frequencies, and we say this is a "low pass filter", because for small values of wT the amplitude factor k is nearly 1 (i.e., very little attenuation of the input signal), whereas for larger values of wT the amplitude factor drops.
		Likewise the phase lag is small when the frequency wT is low, but it increases as the frequency increases.
	www.mathpages.com /home/kmath179.htm (333 words)

	Frequency Response Synthesis (Site not responding. Last check: 2007-11-06)
		At the "corner" frequency, the response is altered by 3 dB and by 45 degrees.
		This is the "zero" and its frequency is associated with the cathode resistor and the bypass capacitor.
		This is the "pole" and the frequency associated with it is associated with the capacitor value and the PARALLEL combination of the cathode resistor and 1/gm (which is effectively the tubes cathode impedance).
	members.aol.com /sbench/freqresp.html (2044 words)

	Understanding Loudspeaker Frequency Response
		Frequency response may well be one of the most misunderstood and frequently abused speaker specifications that any consumer has to deal with.
		For example, the M22ti’s response is stated as 60 Hz to 22 kHz, +/-3 dB, whereas the M80’s is 34 Hz - 22 kHz, +/-3 dB.
		There are, of course, many other reasons why speakers with similar, honestly stated frequency ranges may differ dramatically in price and performance, not the least of which will be determined by the entire family of amplitude response curves that make up the total performance of the speaker.
	www.axiomaudio.com /archives/freqresp.html (1103 words)

	Live Sound International \| Real World Gear - Hand-Held Wired Microphones
		Dynamic microphones do not need an external source of power, can produce a smooth frequency response and a sufficiently high output level to give a good signal-to-noise ratio, and are usually trouble free.
		The mic has a high frequency boost, which might be a problem with monitors, but would be appropriate for an install or church.
		Frequency response is 45Hz to 15kHz with a built-in foam screen.
	www.livesoundint.com /archives/2002/septoct/wired/wired.php (2454 words)

	Sound Card Performance Test Techtalk Frequency Response
		Frequency response is the measure of a sound card's ability to handle music without changing the relative loudness of sounds of various pitches.
		Errors in frequency response is generally thought to be the most audible form of Linear Distortion.
		Frequency response is specified by the combination of three or four numbers.
	www.pcavtech.com /soundcards/techtalk/FR (354 words)

	Optimum frequency response curves in the bass range.
		The gist of this infrasonic response elevation is that optimum curve 7 not only shall be accepted, but also in a room is very near the ideal curve that optimum curve 6 may be considered.
		When the cutoff frequency approaches 60 Hz a somewhat resonant and boomy quality appeared, especially on the male voice, if the remaining bass was elevated to compensate for the lost low bass.
		In a closed room, the optimum response curves 4-7 should be chosen for the most neutral sound, with the greatest safety margin before the onset of audibly distorted sound.
	www.sonicdesign.se /optimum.html (3694 words)

	Frequency Response Characteristics (Site not responding. Last check: 2007-11-06)
		The graph below shows a typical frequency response curve for a proportional (or electrohydraulic servo) valve.
		Curves (a) and (b) show the relationship between ampliyude response and frequency.
		For this particular valve, at an amplitude of -3db (50% output), the frequency response is 10 Hz.
	inprosys.bizland.com /website/freq.htm (383 words)

	MLSSA Room Frequency Response Measurements and EQ (Site not responding. Last check: 2007-11-06)
		Sound engineers who have attempted to equalize a room to a flat frequency response using an RTA and a pink noise source have long realized that RTA measurements are often an unreliable guide to making proper EQ adjustments.
		In the frequency range between these two extremes MLSSA automatically varies the time window length to yield a frequency resolution of 1/3 octave which approximately corresponds to the width of the ear's critical bands.
		After measuring the spatially-averaged room response, EQ adjustments are performed by measuring the equalizer separately; that is, without the need to remeasure the room response each time you do an EQ tweak.
	www.mlssa.com /mlssa/BROCHUREp3.htm (506 words)

	Introduction to Filters
		This document is an introduction to frequency response, and an introduction to active filters (filters using active amplifiers, like op amps).
		To determine the response of a circuit to a sinusoidal signal as a function of frequency it is possible to generalize the concept of impedance to include capacitors and inductors.
		This means that at very high frequencies the capacitor acts as an short circuit, and at low frequencies it acts as an open circuit.
	www.swarthmore.edu /NatSci/echeeve1/Ref/FilterBkgrnd/Filters.html (1211 words)

	Definition: frequency response curve (Site not responding. Last check: 2007-11-06)
		frequency response curve: A plot of the gain or attenuation of a device, such as an amplifier or a filter, as a function of frequency.
		Most amplifiers have a flat frequency response over a certain band, above and below which the gain is reduced.
		The frequency response curve of a filter has one or more peaks or troughs.
	www.atis.org /tg2k/_frequency_response_curve.html (116 words)

	Frequency response
		Microphones are supplied with a manufacturer's frequency range test report, which gives a visual reference for the particular microphone's sensitivity to a given range.
		Sensitivity to the higher frequencies is more significant than ideal flat response overall since much of the highs are lost in further sound processing.
		Frequency response -- The frequency range over which an audio device or system will produce or reproduce a signal within a certain tolerance, such as + - dB.
	lp2cd.com /audio_terms/f/frequency_response.html (172 words)

	Frequency Response Analyzer (Site not responding. Last check: 2007-11-06)
		The 0305 Frequency Response Analyzer is the right system at the right price for measuring low impedances devices.
		In no time at all, the 0305 Frequency Response Analyzer will become one of the most valuable research tools in your laboratory.
		As each device completes its frequency sweep, the next one in the queue is performed until all have been completed.
	www.maccor.com /fra.htm (240 words)

	CTM Example: Frequency Response control of the cruise control model
		Recall from the Root-Locus Tutorial, the bandwidth frequency (BW) (the frequency at the gain M(dB)=-6~-7.5dB) is roughly equals to the natural frequency (Wn).
		Now, the low frequency gain is approximately 20dB (magnitude 10) that predicts the steady-state error of 9%, and the bandwidth frequency is around 0.6 that predicts the rise time of 3 sec (within the desired value).
		Since the low frequency gain has increased while the bandwidth frequency stayed the same, the steady-state error should be reduced and the rise time should stay the same.
	www.engin.umich.edu /group/ctm/examples/cruise/ccFR.html (1016 words)

	Frequency_Response (Site not responding. Last check: 2007-11-06)
		response of that instrument, whereas for the ideal
		Frequency response curves for (a) two violin strings, showing characteristic resonance regions, and (b) a loudspeaker which reproduces frequencies approximately equally.
		: Poor frequency response in a small loudspeaker reproducing a voice at a fast food restaurant.
	www.sfu.ca /sonic-studio/handbook/Frequency_Response.html (121 words)

	Frequency Response (step response method) - Example - Development Library - National Instruments
		to obtain the frequency response of the device.
		Background information: Impulse response is a quick way to measure the frequency response of a device.
		The result is the frequency response of the device.
	sine.ni.com /apps/we/niepd_web_display.display_epd4?p_guid=B45EACE3E6EF56A4E034080020E74861&p_node=175343&p_source=external (336 words)

	Frequency-response curves
		In chapter 1 of this module, the fact was mentioned that an audio amplifier is limited in its Frequency response.
		As you know, this is caused by the fact that the capacitive and inductive reactances vary with the frequency.
		This decrease in the amplifier output at higher frequencies is caused by the interelectrode capacitance.
	www.tpub.com /neets/book8/31b.htm (1015 words)

	Frequency Response of a Bandpass Filter (BPF)
		The range of frequencies between the two limits is refered to as the passband of the filter and the difference between the limiting frequencies as the bandwidth
		determined by the values of L and C. The frequency response magnitude attains a maximum at the resonant frequency.
		A graph of the frequency response magnitude for the parallel resonant BPF is shown in Figure
	www.ee.duke.edu /~cec/final/node113.html (369 words)

	CTM Example: Frequency Response control of the cruise control model (Site not responding. Last check: 2007-11-06)
		Since the bandwidth frequency is roughly equivalent to the natural frequency, a rough estimate of the rise time from the bode plot is tr=1.8/BW.
		There is an inverse relationship between the bandwidth frequency and the rise time, so an increase in the BW will result in a decrease in the rise time.
		The corner frequencies were an initial guess, with some trial and error work, but it seems to do the trick.
	robot0.ge.uiuc.edu /~spong/ge222/matlab/examples/cruise/ccFR.html (1122 words)

	The Frequency Response of Smooth Muscle Stiffness during Ca2+-Activated Contraction -- Shue and Brozovich 76 (5): 2361 ...
		Finally, to eliminate the frequency response of passive components, the frequency response of the passive state was used as
		The frequency response of each muscle cell was processed as described in Fig.
		In the present study we have demonstrated that the frequency response of muscle stiffness obtained during the increasing-frequency
	www.biophysj.org /cgi/content/full/76/5/2361 (4718 words)

	Reasons for Frequency Response Analysis (Site not responding. Last check: 2007-11-06)
		Frequency response analysis is important to us for two primary reasons.
		First, if we know the frequency response then we can predict the response of the circuit to any input.
		Therefore the frequency response allows us to understand a circuit's response to more complex inputs.
	www.ee.duke.edu /~cec/final/node102.html (165 words)

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