| ??? 07/08/12 15:45 Read: times |
#187888 - so far so good Responding to: ???'s previous message |
Richard Erlacher said:
Did you build one of those circuits you discussed? Working on it, but I tested the trigger with two channels with odd waveforms using old cct, one with modulated 1khz signal, the other 20nsec pulses synchronized with the rising edge of the 1khz signal, the good news is this scope does trigger on the little pulses unlike the cheap DSO. How's the triggering? Do you have an attenuator on the output of your circuit so you can reduced the amplitude? How sensitive is this 'scope, i.e. what's the smallest voltage per division that it can reliably display? Can it trigger on short pulses of that magnitude? I will do this test later on, but I think the answer is yes. How about slowly rising waveforms, i.e. a waveform that rises at 1 volt/ms? Does it provide a crisp, clear display, or is it muddied by variations in the trigger voltage? (Nearly any instrument will have some ambiguity in its triggering.) It works perfectly for slow rising signal, in fact you can measure the rise and fall time of the signal with crystal clear display. How does it compare in these regards with respect to your old TEK 475? My old tek475 is junk compared to this one. at high frequency my old tek display brightness becomes dim I can hardly see it, so I made my tek475 work as a component tester in my workshop while I'm having good time with my color dso! What sort of probes did they provide, if any? Are they switchable 1x/10x types? Does the instrument recognize the impedance setting? Yes they are good 1x/10x 300MHz probes with load capacitance of 12pF. The only setting in the scope for probes is the 1x/10x/100x/1000x probes, however the bad news is when I set the probe to 10x the rise time of the signal is degraded and I can no longer see fast rise edges. There's lots of experimentation ahead, before you'll know what the 'scope really does, and how well. TBH this is the best scope I ever had and I'm quite happy with it. my FPGA knowledge is rusty so I'm slowly catching up, I'm almost done playing with DCMs so that I can generate high speed signals to put this scope testing to the limits. Unfortunately the rising time of the scope is <= 1.4nSec as per datasheet, I want to test it with sub nano seconds signals. I don't have modern high end DSO scope to compare it with but I think it is a good value for the money. I will keep you posted. Mahmood |
