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You can't use equivalent time sampling to measure spikes. Equivalent time sampling works only with repetitive/periodic signal (a sum of sines).
The way equivalent time sampling works is by shifting the sampling in time after after a trigger.
Let's say you have a 100MHz sample rate and you want...
What do you intend to do when clipping is detected ?
Just measure Vpp and App and when it gets close to your max range (get's close to clipping), do whatever you have to do (change gain, attenuate, ...).
I believe there are multiple techniques to achieve that, but in principle, high sampling rate of a period is obtained by acquiring samples from multiple periods, which then are interlaced.
Well, the oscilloscope is capable to sample every 10ns, but it won't be able to detect a signal with a full swing in less than 17ns. Effectively, you won't be able to measure rise times smaller than 17ns, even though the sampling period is 10ns. This limitation is due to step response of the...
At 100MSPS a 25MHz signal will only have 4 samples per period. Trying to display signals higher than that would be just unreadable. The maximum theoretical bandwidth is 1/2 sampling rate (Nyquist frequency).
By minimum time step they mean the minimum time per x division on your screen. At 5ns...
Re: Op amp with 120dB PSSR exhibits weird "noise" at 60dB gain when powered by traf
Ugh. I give up. I tried the biggest caps I had laying around to filter that Vcc, but no dice.
But, I replaced the 9V transformer with a tiny old 9V phone adapter and noise is .. puff .. gone. :grin:
So I'll just...
Re: Op amp with 120dB PSSR exhibits weird "noise" at 60dB gain when powered by traf
In the schematics, I replaced C2 220uF with a 470uF low ESR cap which should reduce the supply voltage ripple and should reduce the noise observed at 1000x gain when powered by transformer. But after I replaced...
Re: Op amp with 120dB PSSR exhibits weird "noise" at 60dB gain when powered by traf
I just replaced the 220uF cap with a 470uF low ESR cap and the output waveform didn't change at all. I guess it's not caused by supply voltage ripple.
I wish I had access to an oscilloscope ...
Re: Op amp with 120dB PSSR exhibits weird "noise" at 60dB gain when powered by traf
Oh. Does "Vs" in datasheet refers to "Voltage signal" or input swing? I thought it refers to "Voltage supply".
Re: Op amp with 120dB PSSR exhibits weird "noise" at 60dB gain when powered by traf
Yes, there is no second ground connection besides neutral, so no ground loops.
Yes, during the battery test, the neutral was still connected.
Actually, the op amp output is fed to an 5KHz PWM, then transferred...
Re: Op amp with 120dB PSSR exhibits weird "noise" at 60dB gain when powered by traf
My Vs is 5V. Not sure what are you suggesting. Limit non-inverting input from 2.7V to 5V ?
Re: Op amp with 120dB PSSR exhibits weird "noise" at 60dB gain when powered by traf
Yes, the circuit ground is connected to neutral. This is done so that the voltage on R20 can be measured.
There is no oscilloscope. The plot is obtained from the data saved on a SD memory card by the...
Op amp with 120dB PSRR exhibits weird "noise" at 60dB gain when powered by traf
I have built the circuit in the schematic bellow which seems to work acceptable when is powered by a 9V battery.
The circuit measures the current in the mains by the means of an very small resistive shunt (R20...
OK, I found a much better solution than mine that uses a trigger schmidt and a integrator, but for some reason the circuit doesn't oscillate in Proteus.
https://www.edn.com/design/analog/4312118/Single-IC-forms-precision-triangular-wave-generator
I designed a 3V pk-pk 7KHz triangle signal generator following the NE555 datasheet application, as shown in the picture below.
My only fear is though, that the signal might not look as good as in the simulation, considering that the op amp is at it's very edge operating at >7KHz with 100x...
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