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23 Threads found on Feedback Cancellation
did you try to reverse the speaker polarity? If feedback is in phase at >unity gain, it will cause oscillation or howling. IF phase shifts 180 deg, at different f, but at a higher feedback, then a quality factor of non-linear response as AG indicated is your problem. Generally cheap mic's have background noise cancellation by having a (...)
Hi, Can anyone suggest me DC offset cancellation circuit for high frequency application (50 MHz) circuits. I used the continuous time feedback model circuit include LPF+OTA, but it degrades the opamp gain and linearity at common mode output votlage range. I am not sure the sampling clock based DCOC will work for high speed applications or n
The howling is not caused by echoes. Instead the howling is caused by the speaker sound being heard by the microphone then is amplified. Since the telephone line has only two wires with transmission plus reception on it then the telephone circuit must use a hybrid circuit to cancel the feedback. Most cheap speakerphones use "voice switching" that m
Hi, I am simulating this RX. Had a problem with the feedback loop. 113960 113961 I am wondering why the feedback voltage (output of the opamp) cannot be centered about the output voltage of the TIA, so that the final differential eyediagram cannot be centered around 0V, it has offset. I checked
Of course, chrutschow is right - and his arguments hold also for the case that there is only capacitive feedback (integrator applications). Another remark: It seems that the presented simulation results are not correct (not enough simulation steps in the active region).
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.
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..................
Dear sir/madam i need matlab coding for adaptive feedback noise cancellation in hearing aids using adaptive filter. the input as a speech signal.
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
I think I understand what you are saying, but the amount of capacitance required would depend on the gain in order to just cancel and not cause oscillation. I have used positive capacitive feedback to remove the gate capacitance of fets, the capacitance of a photodiode, and the stray capacitance of compensation networks but it relies on having a c
I wander whether you drawed the schematic completely. I designed a fourth order filter with DC offset cancellation.the feedback block acts as a LPF to extract the dc signal of the output. And the BW of the LPF is very the value of R and C is very large. For the main signal path,the load is only R. when you design the amplifier, This shoul
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.
Hi guys, I'm working on a dc cancellation circuit in a optical receiver circuit. Currently, i'm facing a problem in designing a low noise opamp for my feedback circuit. The function of this feedback circuit is to compare the dc voltage at the positive and negative input terminal of the opamp to be 1.2V and substract the input dc current (...)
Hi, I'm desigining a Transimpedance amplifier with the bandpass response, which means the differential output of the TIA is feedback to the input of the TIA for DC cancellation purpose. My question is, how do I calculate input referred rms noise of the TIA in Cadence. I understand that for the forward TIA design (LPF response), i can run the noi
someone tell me that the dc offset is detemined by the layout qualitfication. I think this will be controlled not solve,but how? someone tell me that there are some digital calibration technique to control the bias?but this maybe too complicated a technique. can anyone offer some details of the dc offset calibration technique in the picture.
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?
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
Guys, Can someone explain me what are the advanges & disadvantages of using the Feedforward & feedback Offset Voltage cancellation in Circuit design. Thanks, suria3