We’re rewarding the question askers & reputations are being recalculated! Read more.

New answers tagged

0

You are seeking the largest possible dynamic range, bounded by thermal noise floor at lower levels, and with distortion (possibly also SlewLimiting) at the upper levels. When you double the Vout of an opamp, the input differential_pair distortion will soar (2nd order product double, 3rd order products quadruple) because millivolts of differential input ...


0

In terms of practical theory, all components have the ability to add noise, from reacting to external (emi) and internal (heating) sources of input you don't care for. Nothing changes instantaneously so everything has some frequency-related characteristics. As a general guess, yes several identical stages do tend to result in lower noise than something ...


0

Differential signals are often used where EMC is a concern, as interference is usually common mode and a differential signal on a close pair will radiate less. The EMC enemy is more often common mode noise or emissions. Your suggestion would be more useful in situations where you need multiple signal paths and want to do as much as possible to ensure they'...


0

Yes some low pass filter is common and essential. Technically it's called a transient suppression filter for : Conducted load transients V=LdI/dt, radiated crosstalk and anti-alias suppression (where the rise time interferes with an error of the sampled value) . The details of the filter need to be defined in terms of your needs for timing and accurate ...


0

Look at the diagram one row of figures up, on the right. Pin 3 is your output voltage, and is connected to ground (not -15) through a 10K resistor. I don't know what you mean by "das"


1

Most interfering noise on a cable is coupled equally to both conductors when certain cabling precautions are taken and these are twisting pairs (to reduce magnetically induced effects) and screening (to reduce electrically coupled effects). But, to ensure you handle correctly the common mode voltages on both conductors in a pair, you need to have a balanced ...


0

Consider this drawing of two circuits; the 2nd circuit has many intentional IMBALANCES. These imbalances degrade the DC CMR and the AC CMR. Notice the first circuit has gain of 1. Notice the 2nd circuit has gain of 1,000. simulate this circuit – Schematic created using CircuitLab


1

The esp32 is capable of 27.2 ksps or 27kHz, so just about any instrumentation amplifier or operational amplifier would be fine for the purpose of subtracting channels, especially since the gain will probably be reduced to the 3.3V scale. The best thing to do would be to use a comparator stage after the instrumentation amplifier with a low noise DAC to set ...


1

I am planning to measure an RS485 signal with an oscilloscope. And... In my application, the transmitter circuit's reference ground(also the signal's ground) and... Here's the contradiction. There are two basic signals in RS485 - they are differential and balanced and they need to be so. If they are not then it's not RS485. Then you say that the ...


3

But I'm wondering, what would happen if Vin1 went up by 10mV, but Vin2 stayed the same and didn't go down by 10mV. You need to work out the common mode and differential components of the input. For example, your scenario is the same as both inputs going up by 5 mV, then Vin1 going up by another 5 mV while Vin2 goes down by 5 mV. Roughly, the output would ...


0

In normal circumstances, Vin1 and Vin2 change differentially, if Vin1 goes up by 10mV, Vin2 goes down by 10mV. Makes sense. No. This is your specific input signal. That's not the "normal" case. It's the symmetric input special case. But I'm wondering, what would happen if Vin1 went up by 10mV, but Vin2 stayed the same and didn't go down by 10mV. The ...


0

The DC and low frequency gain is expected to be low since the ratio of r3+r6 = 6k. Is much less than the collector resistor R4 (700ohm) - 13dB sounds plausible. The rise at high frequencies is presumably because of the gate to drain capacitance of the JFETs. Notice the change of phase - low frequency is through amplifier action. The HF is through direct ...


1

Am assuming that a differential-output instrumentation amplifier offers a low output impedance on both inverting and non-inverting outputs....something to check on its data sheet. Having low output impedance makes filter design easier. In any case, consider adding a front-end low-pass filter to the instrumentation amp, if only to take out radio frequency ...


0

Those are simple one-pole low-pass filters for antialiasing, and you're unlikely to find an analog for band-pass and high pass. Arguably, a sound approach is to touch your signal as little as possible prior to sampling. A nice gentle one-pole low-pass, if you have the room to do it between your signal of interest and your Nyquist frequency, is a great ...


0

like having the "differential capacitor" be 10 times the value of the "common mode capacitors." There's potential for a misinterpretation: The article is not telling you to generally use 10 times the value for the same cutoff frequency, but to design a filter to help the common mode filter. Since whatever is attached to the differential filter shouldn't be ...


2

You have to keep the inputs within the input common mode range. Typically with an instrumentation amplifier that depends on the gain as well since there are internal nodes that can saturate for some designs, however in this case the manufacturer lists the range for G=1 as +1.9V to 12V-1.4V = 10.6V. Obviously your inputs are both within a couple hundred mV ...


1

Unless you have experience with common-mode noise, modelling coax, stripline, microstrip, ground effects and understand the group delay distortion effects of unequal skew paths down to the millimeter and know what an eye pattern looks like and how to optimize, you can easily destroy the integrity of a data signal as you suggested. NB7VQ14MMNG is a popular ...


Top 50 recent answers are included