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Feedback Cancellation

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I designed an electret microphone (single ended) amplifier (recommended by the chip itself) which works well, only if the speaker is very far to the source. The reason is that audio feedback is worse when mic and speaker is close to each other. The attached design below is an input to the codec (WM8991 if you're aware). But if any of you can help f
hi everyone, i'm working in my thesis named acoustic feedback cancellation system in Matlab. i have 3 most important doubts , if someone can help me with this i really would apreciate it: 1. which software is better for this, PUREDATA OR MATLAB. 2. is it better the use of adaptive filters or the implementation of notch filters?. 3.HEEEEEEEEEEL
Guys, Can someone explain me what are the advanges & disadvantages of using the Feedforward & feedback Offset Voltage cancellation in Circuit design. Thanks, suria3
Dear sir/madam i need matlab coding for adaptive feedback noise cancellation in hearing aids using adaptive filter. the input as a speech signal.
Would any people like to introduce me some good book or material,which describe the detail of DC offset compensation feedback of multistage-amplifier? I am currently working on high-speed limiting amplifier, however still not clear about the usage of the DC feed-back. Personally, I think it make the circuit operating point insensible to pr
Hello all, we would greatly appreciate if the respected auditorium of this forum could provide us with their feedback on the noise reduction techniques we have developed. Please download our demo noise cancellation software at: Thank you very much and we are looking forward for your feedback!
Hello All, I need to implement a simple voice amplifier. I have no flexibility on microphone or speaker location and I'm affraid I'll have acoustic feedback (howling). Is there some purely analog method or IC for acoustic echo cancellation? I wonder about hands free telephone operation.... Have they such kind of circuit? Thanks in adv
Guys, Currently I'm doing research in Optical Receiver design consist of Transimpedance Amplifier and Limiting amplifier. I noticed that in the fully differential Transimpedance amplifier circuit design, there is a offset compensator at the output of the differential TIA and feedback to the dummy TIA.Then when it goes to the next stage of cascad
In the article "lineariztion technique using digital cartesian loop transmitter" , the author said "as with all feedback systems, its performance is limited by the delay around the loop and hence the linearity improvement which can be obtained depends upon the bandwidth over which the feedback must operate." I don't know the "bandwidth" is RF bandw
using negative feedback in baseband amplifiers reduces the DC-offset. does the accuracy of this DC-offset cancellation depend on the magnitude of the input DC-offset voltage? I mean, the higher the input DC-offset voltage is, the better the negative feedback works?
A DC offset cancellation circuit uses a feedback loop. The bandwidth of this loop can reshape the bandwidth of your amplifier. The design of the loop needs careful design in terms of delay, frequency response and stability.
In direct convertion (Zero-IF) RX system RX DC offset must removed. In such an WLAN receiver high pass filter with low cornner frequendcy is often used to remove the DC offset. There are two ways to realize the high pass filter. (1) using AC couple directly to remove the DC offset. (2) using a negitive feedback with low pass filter to extract the D
HI....I need matlab codes for mutiple feedback successive interference cancellation in MU-MIMO...... can anybody help ?waitin 4 reply.....need materials to study BER performance too..................
DC offset inputs do not affect gain. If you apply DC offset to a differential amp, the main factor is the equivalent resistance in feedback ratio or input attenuator ratio is constant. If the offset only introduces a DC signal from a relatively constant impedance source to null the offset ( in a feedback loop), then the gain is constant.
Hello, Folks, I am looking for a pair of Active Noise cancellation (ANC) headphones that could cancel human speaking. But almost all headphones in the market are just cancelling the low-frequency noises such as engine or fan. I do not understand why the higher-frequency parts of human voices could not be cancelled since ear hearing spectrum j
I know that the current trend for Echo cancellation is the use of DSPs. Does any one know or can point me to alternate method where echo cancellation is done using a microprocessor? Thanks JJ :roll:
do I need to break combinational feedback loop at all conditions? How can i break combination feedback loop.What do the command set_disable_timing do to the combinational ciucuit in DA? thanks!!!
Is a 32 page description of Prof. Middlebrook's famous feedback measurement theory.
It is inverting with positive feedback but you can hardly say it is an amplifier if it is made with op amp. All depends on open loop gain of amp and value of resistors.
I was wondering if anyone has had the opportunity to use any of the Icinergy software feedback would be of great help regards, PD
Hello all, I'm intend to construct a Force feedback joystick. Anyone had already make any thing like this ? Please I need if possible some standards or examples of signals that PC send to device, during a Game ... I'm very glad if someone could help me. Any help is welcome ... Thanks in advance. Best regards, Renato
for common mode feedback circuit stability ,need what conditions ,how to tune the circuit to satisfy the conditions thank you very much ,I am a tenderfoot for here ,wish help each others.
Hi all, Good paper and tool about General feedback Theorem simulation ynhe
Can someone please help, I require the source code for Line Echo cancellation to add to my Dsp project. Thanks in Anticipation :roll:
Are you sure that you need a asynchronous comparator? Usually the comparators used in the ADCs work synchronously with the clock signal. If it is a synchronous comparator (controlled by a clk signal) you should use a regenerative structure, which employs positive feedback. There are several known offset cancellation techniques. If it is asyn
hi all I just read an article about the EMC in PCB, there is a phase "flux cancellation", I don't know what meant it is? could you tell me? thanks. else, what's meaning the "chassis ground " best regards!
Change the comparitor for an opamp and decouple the feedback loop. Make sure the opamp is being biased correctly. Make sure that there is always a load on the output ( use a resistor 4.7kohms). Barrybear
can it be connected in feedback mode other than connecting two inputs to vcm
hi all where can i find this book schaum's feedback and control system ..... thanks for your help
Common-Mode feedback tutorial
Dear All : I work on LDO design , the chip is come back , We use external PMOS . and we use feedback circuit to control the LDO , this is very populart structure , But now the Circuit have some problems , the OPen loop of OP is correct , But when we connect the closed loop , The OP's behavior is wrong , I find the PMOS gate has some l
Hi All, I want to design differential IF feedback Amplifier. Can someone suggest some references? Thanks
has anyone ever dealt with this device? i have found it has a patent as well as a web site that has schematics they seem to be fine but has anyone actually used/heard of one being used. any feedback on the subject would be most welcome
Negative feedback help the transitor circuit independently with temperature. Less dependent on temperature! Never indipedent unless is ideal case just less depedent it is. Also negative feedback makes things better predictable. Helps in distortion and nonlinearity of active device to be better tailored, hence h
I want to express the feedback of turbo codes in polynomial, but I do not know the difference when i express the feedback of (1, 17/15) and (1, 17/13).Which is the expression of the polynomial 1+D+D^3. Thanks.
The negative resistance or the reflection coeficient >1 is for 1 port circuit. For example if you design a DRO that the DR is coupled to the Gate port and the source is loaded by a capacitor when the output coupled to the drain, you can look first at the gate, tune the source and drain loads parameters for a negative resistance at the gate port and
Yes. Another way to remember is to see which parameter in the output is sampled by the feedback network. As additional information, that parameter will be kept constant by the feedback system. This influences the circuit output impedance. If the voltage is sampled, it will be kept constant which will make the circuit output impedance smaller th
The feedback resistor looks like Rf/Av to a source *feeding* the amp. Looking from the output the feedback resistor is just Rf.
Hi, I saw a system in a glass manufacturing company that uses a PLC to control the speed of two motors, such that the difference is some constant. It uses two tachometers for each of the motors as a control and a feedback signal (one motor speed is changed manualy, the PLC function is to vary the other's accordingly). It has a lot of problems su
The common-mode feedback is a negative feedback network that must be used in all amplifiers with differential output. This is because the feedback network external to the amplifier only sets the differential output voltage. For example if the gain of the circuit is 2, then the differential output voltage will be 2x the differential input (...)
All know,to prevent from alias we insert a AAF(Anti-Alias Filter) between input and the following ADC which is designed with SC(Switch Capacitor) Circuit. But how about using SC circuit in AAF for common mode feedback?Does it result in alias?
Hi ! Just want to ask why the speed of feedback path is normally slower than the main signal path? Let say the main signal path is 3G, but the feedback path in the range of few MHz is good enough? My personal opinion is with the lower speed in the feedback, it will give more accurate result. Any other opinion?
The governor on a steam engine is feedback, the faster the engine runs, the centrafugal force throws out those balls, and the engine is controlled and hits a steady speed. I wonder how that would look descibed in calculus? Unless you are studying to pass an exam, don't worry about it to much. Modern circuit design is like Leggo, just stick the rea
Voltage feedback will always give higher input impedance. Current feedback will always lower the input impedance. Otherwise it depends on what sort of signal u are tapping at the output if feedback type is v o/p - v feed=>voltage amps => high i/p and low o/p res higher volt gain i o/p - v feed=>transconductance amps => high o/p (...)
The limiting amplfier is normally multi-stage cascaded. This required a DC negative feedback to provide offset cancellation. My question is how we get the relationship between the lower corner frequency of the amplifier and the R, C parameters? Why it is related with the gain of the amplfier stages? What is the impact if the lower corner fr
How Switch Capacitor common mode feedback works for OTA?
Please share, notes papers, related links with feedback control theory applied to analog circuit design, for example: Design of amplifiers Design of regulators, analog and switched Design of Power converters Design of Plls Design of AG amplifiers and any think you have related with the condtion: analog design from the viewpoint of feed
In infineon's application note ''W-CDMA 2.3ghz vco using bfr360f and bby58-02v'' they said: ''traditionally, all oscillator are classified as either a negative resistance oscillator or a feedback oscillator." who can explain in which frequency band design, can using the negative resistance theory? 300MHz or GHz above? thanks!
I solved the blow quastion but in solving with kvl_kcl solution got this for gain of circuit : (ab(c+1)/(ab +b +c+1)) but with feedback solution ( "Gray & More" 's book) I have this solution: Gain=(ab(c+1)/(ab+c+1)) Picture of circuit is attached blow
No, you don't need initial conditions to simulate you negative feedback system. You may need .IC, however, if your schematic is large and complex, just to help it find the operating point or start running, but this is a different matter. Do run a step responce of your system to see if it settles well, meaning not oscillating.