[Coco] RGB to VGA boards, test equipment needed

[Kandur]

Thanks Steve.
Please read my reply to Gene, where I'll clarify my needs.

Kandur

Sunday, September 6, 2015, 1:54:22 PM, you wrote:
> They say good for audio, which makes sense. Video signals are going to be much
> used one...if I were to buy one today, I'd want a decent 100mhz Dual Trace

> On Sep 6, 2015, at 1:19 PM, Kandur <k at qdv.pw> wrote:
>> Would these pocket oscilloscopes do for checking video signals?
>> If yes, wich one is better? Are there any others under $100?
>> http://tinyurl.com/p9jx2ec
>> http://tinyurl.com/ommymqs
>> Frida y, September 4, 2015, Barry Nelson among other things wrote,
>>> At 15khz a .1 uf capacitor has an effective impedance of 106 ohms but at the
>>> color burst clock frequency of 3.58 mhz, the same capacitor has an impedance
>>> of 0.444 ohms. Since the CoCo 3's composite video output circuit has a 10 ohm
>>> resistor on the collector of the output transistor and a 120 ohm resistor on
>>> the base, putting a .1 uf capacitor from the video output to ground should
>>> effectively ground out the high frequency color burst signal and part of the
>>> black and white video, but should leave the horizontal and vertical sync
>>> pulses virtually untouched. This should eliminate the jitter on the 80 column
>>> screen. If the capacitor doesn't do it by itself you could a small 10 ohm in
>>> series. This has the advantage of providing sync as well as a proper black level reference signal.

>> Thanks,
>> Kandur


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