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Feedback Effect

99 Threads found on edaboard.com: Feedback Effect

N-path filters & their flicker noise of clock generation

flicker noise is a relatively low frequency effect that "upconverts" to the RF region. So if you can lower the flicker noise of the device itself, you will have less clock jitter. Some sort of audio frequency feedback loop to bias your oscialator transistor, keeping fets outside of their voltage range extremes, applying analog feedback (...)

I want to understand how the reverbration effect is implemented, where to start?

The book DAFX - Digital Audio effects by Udo Zölzer has a good chapter about reverberation. Simple reverberation effects can be made by superimposing multiple delays and adding some feedback.

CMRR test circuit for current-feedback opamps

I've been studying CMRR for voltage feedback amplifiers and I came across this document from analog devices figure.3(attached) in the document it shows a circuit to measure CMRR, which is

Precision rectifier for hall effect signal conditioning

Whenever the voltage input of the 2nd opamp gets near ground then the diode turns off and the two resistors connected to the capacitor slowly discharge it. The negative feedback resistor R5 has its value changed to change the gain then the discharge time is also changed. The value of R4 can also be changed to change the gain.

Question about lighting for a small project

Hi guys, currently, I'm working in the design of a small robot for a nice personal project. I would like to put a feedback illumination signal, and I like a lot the effect I saw some time ago in a Disney park (please see video attached). As you can see in this small video, it's basicaly a light spinning continously, I can't see any discrete l

Is there a negative miller effect?

Yes - such a capacitor between C and E in common-B configuration provides positive feedback and, thus, increases the input impedance for rising frequencies. This can be also described by the term "invers (negative) MILLER effect". However, at the same time, the gain decreases (C parallel to Rc). Why do you expect an RHP pole? [SIZE

Relationship between ELD and OSR?

Higher OSR results lower quatization noise level at feedback. So effect due to ELD can be alleviated. See pp.213-215 of the following. BTW, it seems that 2nd edition of this book is published this year. Hi pancho_hideboo: Thanks a lot! D

Representation/Effect of a delay element in the frequency domain?

1. You have been asking about delay not gain. 2. Delay in a feedback loop affects the phase margin and in so far the closed loop behaviour

[Moved]:Is it possible to "see" Early effect and miller effects in simulation or osci

Early effect both in simulation and oscilloscope, s. the following image: 117930 For BJTs, instead of Id vs. Vds plot Ic vs. Vce, with Vbe as parameter. Va is the Early voltage. Miller effect depends on circuit design, feedback and signal amplitude, so I think an analysis method (simulation) is more suitable.

Why is the current ringing in this resistor in this LTspice simulation?

The LTC6101 model is apparently instabble with larger Rin values due insufficient compensation of the feedback amplifier. No idea if the effect occurs with the real IC.

effect of commom mode feedback on CMRR of a telescopic opamp

Generally, commom mode feedback (CMFB) improves the CMRR of (any) opAmp by keeping the CM output well within the CM output range for a wide range of CM input.

Working of op-amp in below circuit

It's a somewhat odd circuit. There's 2.52V on the plus input to offset the output by that amount. The op amp acts as an inverting amplifier with three feedback circuits. The series output resistor may be to make the circuit stable with high capacitance output loads, but that's not entirely clear to me.

Tuning input and output impedance without effect on each other

Use "simultaneously conjugate matching" technique if you play in a narrowband.You can find some information about it in textbooks. Bu I guess you design a wideband LNA and this technique is not valid in that case.Instead, check your feedback circuits ( series and parallel ) to stabilize inout and output impedances.Since S12==0 , you will see simil

difference between DC small signal gain and AC small signal gain ?

The capacitance of a transistor and its wiring is a filter and produces negative feedback from the collector to its base due to the Miller effect which reduces the hfe AC small signal current gain. The hFE DC small signal current gain is not affected so it is the highest. Fairchild's datasheet for the 2N3904 transistor shows a graph of the hfe AC

The effect to output impedance from positive feedback

The influence of a small amount of positive feedback - as long as the system remains stable - can be found using the same formula as for negative feedback, however using a POSIVE sign for the loop gain. (Stability limit for unity loop gain). Example: Voltage controlled feedback (as for operational amplifiers): Zout=Zol/(1-A,loop) with (...)

Is it possible to use feedback network to change an OTA to a real OpAmp

If you compute the output resistance, you can see the effect of feedback (resistive feedback R1-R2): Rout=Rota||(R1+R2)/(1+gm*R1) gm: OTA transconductance. You can see that the OTA output resistance is reduced - however, only by the factor gm*R1.

A question about compensation capacitor in the opamp

(1) the high impedance node ("this" means the latter one). Voltage feedback should always occur from a low impedance to a high impedance node. (2) The compensation capacitor has no effect on AC swing. It serves as Miller compensation cap to separate the poles of the previous and the following stage in order to achieve one domi

effect of Rg on gain of CS stage

If the stage is then driven by a small signal voltage which has zero output impedance, the feedback through Rg will be shorted out by the source, and Rg will have no effect on the gain. If the driving source has an output impedance greater than zero, then Rg will have an effect on the gain. To determine just what the (...)

How RF signal appears on the gate pin of series-feedback microstrip oscillator?

Not S21. Maybe you meant S12? Think also the "Miller effect". How the equivalent input capacitance of an inverting amplifier gets whatever little feedback capacitance existing between the input and output terminals amplified by (1+Gain). For an oscillator, there has to be some way a portion of the output gets to wiggle the input gate r

Circuits that allow resonant frequency

What type of circuit allows resonant frequency and blocks non-resonant frequency? and why? A circuit that exhibits an effect called "resonance" can also be realized using an amplifier with 2nd order RC feedback. However, independent on the realization (passive or active) you should know that such a bandpass circuit a