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Gw Instek GDS2204E (200MHz 4 channel DSO) review

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nctnico:
When it comes to aliasing you also have to realise that the roll-off mirrors at half the sampling frequency so higher frequency signals past the Nyquist frequency still get attenuated as if the response continued.

jjoonathan:
True, I should have made it more clear that the numbers I gave were the worst case, where you have a signal just above the Nyquist frequency aliasing to just below the Nyquist frequency. It's an edge case to be sure, but like many edge cases it punches above its weight. It pops up right at the theoretical limit of what a scope can measure, and given that bandwidth costs money and both oscilloscope bandwidths and clock/data frequencies gravitate towards "nice" round numbers, it's an edge case that I could see someone hitting if they weren't careful.

nctnico:
Since there are no other graphs available I measured the bandwidth of my GDS2204E starting at 10MHz with 1 channel enabled at 1Gs/s. I noticed that switching to a more sensitive range changed the amplitude more than I expected so I measured twice using a 0dBm signal and a -20dBm signal and plotted the results in a graph (Y-axis in dB, X-axis in MHz):


The 50mV/div graph shows the -3dB frequency is around 290MHz but for 10mV/div the -3dB point is around 210MHz.

Merlot1970:
I unboxed my new GDS-2204E yesterday and fired it up..  About 15 minutes into using it, I was able to find a problem on a circuit I"ve been working on..It appeared on screen to be a high impedance power supply causing a glitch at the starting point of my circuit.  My Tek analog scope did not see this, but the Instek picked up the glitch immediately.  I'll see If i can post a photo.


First photo is the captured glitch...When the circuit initially conducts current, it wigs out.

Second photo is the corrected problem.

saturation:
Good to hear, would be interested in why the Tek couldn't pick it up and what the Instek had that found it quickly.


--- Quote from: Merlot1970 on September 19, 2016, 07:22:49 pm ---I unboxed my new GDS-2204E yesterday and fired it up..  About 15 minutes into using it, I was able to find a problem on a circuit I"ve been working on..It appeared on screen to be a high impedance power supply causing a glitch at the starting point of my circuit.  My Tek analog scope did not see this, but the Instek picked up the glitch immediately.  I'll see If i can post a photo.



--- End quote ---

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