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Composite video into Tektronix Waveform 1731 / WFM601-A scopes?
I’m a little obsessed with old scopes, it’s not a serious habit just a minor one, anyway…
A few months ago I got hold of a working pair of Tektronix 1731 and Tektronix WFM601-A scopes, which soon after (because I know nothing of broadcasting standards!) I discovered expect SDI inputs. Having absolutely nothing that generates SDI signals, I ordered a CVBS+VGA to SDI converter off Amazon, which turns out to accept composite video signals but will not output SD-SDI signals, which I think is what I need. :/
Can anyone give me any advice on what I should be looking for to convert composite video signals into a format the Tektronix vectorscope/waveform monitors can digest and enjoy?
I see a lot of things on ebay, but I’m not sure if it’s the ignorance of the sellers, or more likely the assumption that buyers understand what all the outputs are for, they just don’t tend to say what the output formats are or do, and as much as I like having a museum of old equipment I really don’t have the space (or money) to just randomly buy them. ☺
TIA
R.
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5 Replies
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Your TEK 1731 should accept analog inputs. If you feed it a composite signal it should work fine. Your TEK-601 will be looking for standard definition SDI inputs. What analog to digital converter are you using? Brand/model?
Not my monkeys. Not my circus.
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Thanks for the reply!
The converter I have (which doesn’t do SD-SDI despite saying so in the advert, the instructions that come with it only list 3G-SDI and HD-SDI as outputs :() is this one, the Wiistar:
https://www.amazon.co.uk/Wiistar-Converter-support-outputs-Adapter/dp/B01DLYCXW4 -
Yes the specs for the converter do indicate that it should output SD-SDI (480i). I notice that on the photos there are buttons for Mode and Format. Are you sure that these are set properly for standard definition? What are you using for an input to the unit?
Not my monkeys. Not my circus.
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Yes I’m sure, the tiny manual is pretty clear on what it outputs, it only lists SG-SDI and HD-SDI, and 720 is the minimum vertical resolution. I’ve tried a few composite signals, mainly old computer equipment (and a handheld device which supports it), and the unit definitely locks onto the signal properly. :/
So I’m pretty sure the converter is outputting SDI, but not in a format the Tek’s can deal with because it’s too new for them.
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If your converter outputs SD-SDI, which it appears to do, it should be able to use the scopes to look at the signal. Make sure that your converter is set to SD-SDI (480i is 720×480 or 720×486 depending on it’s firmware). 720p is not standard definition-it’s an HD format. You need to set your converter to 480i in order for the scoped to take in the signal.
Not my monkeys. Not my circus.
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