redrumloa auction: DPS Personal V-scope NOS!

[redrumloa]

Click here to see auction listing

[csirac_]

Damn... a real vector scope is quite expensive indeed!

I see the current bid is $1 USD. You must be a bit dissapointed at that ;-)

It would almost be worth setting up a dedicated classic Amiga with this thing as a real piece of bench equipment... I dont do any TV repairs, so I wonder how useful it is as a CRO?

- Paul

[MAD]

Hoya!

Sorry to be that thick but WHAT is it???

Be funky

M A D

[csirac_]

A vector scope is used in the repair of TVs. A normal CRO can only show you instantaneous voltage/vs time or voltage/vs voltage, whereas a vector scope can do some funky "demodulation" for you and can show you phasors... so, it should be able to break down baseband composite video so you can monitor it's different components: luminance, chroma, sound (L+R)/2, sound R/2, colourburst..

That left hand image with all the compressed sine waves at differnt levels looks like it is showing you at least part of a single line of TV - the colour burst on the "back porch", followed by part of a vertical white bar (white is the lowest signal level in TV, since TV pictures are inherently "not black", white has the lowest level so that less transmission power is used on average)  then the staggered steps there would be your "active line" information - obviously it's showing a test pattern that consists of some vertical bars, perhaps it is that test pattern in the third picture there, which actually has a vertical white bar as the first colour.

Actually if you count the number of steps on the left image after colour burst, there are 7, and there are 7 colour bars on the right hand test image.. I hope my exam tomorrow goes well ;-)

I've not actually used a vector scope but I'm pretty sure it's along those lines :-)

- Paul

[Edit - looks like the documentation for this suggests that was also used to monitor the baseband video signal for day to day  broadcasting at transmitter stations/studios - I guess that makes sense, it would be the "dials and guages" for the engineers/operators maintaining the transmitter equipment. Vector scopes would also be invaluable for evaluating the performance of and debugging new television prototypes, I guess...

Actually vector scopes wouldn't have to be TV specific, it would be handy to have phasor relationships on screen for other radio-related things as well.]

[redrumloa]

I see the current bid is $1 USD. You must be a bit dissapointed at that

No not really :-P  I have faith the market will bear fair value. So Paul, why havn't YOU bid yet? You seem to be an expert at this :-o

BTW: I have 2 A2000s available also if needed. They will be listed to eBay shortly.

[Framiga]

Quote

No not really I have faith the market will bear fair value. So Paul, why havn't YOU bid yet? You seem to be an expert at this

BTW: I have 2 A2000s available also if needed. They will be listed to eBay shortly.

Note that it is NTSC only and requires an ISA slot (the same board works on Amiga and on PC) and it is crontrolled via software through the serial RS232 port.

It is a great item for american/jap users.

Ciao

[csirac_]

by Framiga on 2003/6/23 23:35:59

It is a great item for american/jap users.

Ciao

I'm in Australia, so an NTSC product isn't that useful here either, however I find it hard to imagine that a vector scope can be intrinsically NTSC or PAL or SECAM, etc. It would just be the software that is different, surely... NTSC differs from PAL in the bandwidth it uses (less lines); the field frequency; it lacks the "Phase Alternating Line" part of PAL (which helps to compensate static phase error in the PLLs in the reciever that lock on to the colour burst and decode colour); NTSC has different gamma/phase encoding for colour; and I guess the subcarriers for sound etc. are different frequencies...

Ok so they are fairly different ;-)

@red:
I'm just arguing with myself whether, since it is just a monitoring device, it would work for PAL, but besides that would it be useful for other things.. I already have so much junk.. I have an A4kec030 and an A1200.. mmmmm. Naah. I'd need a credit card for starters ;-)

- Paul

[Framiga]

by csirac_ on 2003/6/23 15:26:13

Ok so they are fairly different:-)

Absolutely not compatible.

There is a DPS Waveform Monitor/Vectorscope board for Pal also. . . .however i have a Tektronix WFM and separate V-Scope Pal only companion for my job.

Ciao

[redrumloa]

Naah. I'd need a credit card for starters

Nope, I accept PayPal, money orders and cashier checks as long as it's in USD.  :-D

[jeffimix]

Well, it's 154$ now, good job. If this thing work on both PC and Amiga, wouldn't you only need an NTSC capable monitor- not Amiga??? PC compatibles don't work in NTSC.

[redrumloa]

If this thing work on both PC and Amiga, wouldn't you only need an NTSC capable monitor- not Amiga???

Correct, the Amiga need not be ntsc. However it's usefulness AFAIK would be more geared to NTSC markets.