An idea for s source for o,scope deflection amplifiers.
On Feb 28, 12:16*pm, "N9WOS" wrote:
The hardest part to build on an oscilloscope (while still maintaining
bandwidth) is the final deflection amplifiers.
Something had occurred to me a little while ago. There is a readily
available supply of chips that will do the job in a specific product. That
product is CRT SVGA monitors.
....
Wow, I admire you for even thinking of tackling something like this!
You're right that the video drivers from modern fast monitors should
work fine for deflection amplifiers, perhaps with a bit of care about
frequency compensation, and so long as they have enough output to
drive your particular CRT.
On the other hand, it does seem like a LOT of work to go to
considering that you can get a really nice used analog scope for under
$100. I have an HP1715A 200MHz 2-channel scope with nice main+delayed
sweep that I need to put on ebay (or equivalent), and I seriously
doubt I'll get $100 for it.
If you do go to all the trouble to revamp your Eico (maybe the same
scope model I started with almost 50 years ago??!!), I do hope you'll
put a good triggered sweep in it, and not just a "horizontal
oscillator." It's not too difficult to make a very respectable linear
sweep with op amps and fast comparators these days. For triggering,
for example, have a look at the Analog Devices ADCMP02 and its
siblings: fast, built-in hysteresis... I'm using one in the input of
a counter, and it goes to 100MHz easily for low level inputs, and to
well over 200MHz if I jack up the input a bit.
Cheers,
Tom
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