Nova Systems Time Base Correctors

[ARC Tech-109]

Anyone have experience with the Nova Systems Digital 700 or Digital 800 Full Frame TBC's? I can't seem to find anything around for the front DIP switch settings and neither one is very cooperative at the moment. They're both from 1992 and it appears that Nova has gone out of the TBC business.

Thanks in advance
Brett

[kf4rca]

Most likely the dip switches are for the number of lines of advance for the vertical drive. I believe it increments in BCD counting. What are you using for a reference. I'm not sure if this is a stand-alone unit. Most TBC's require an external reference (black signal) to reference to. What are you using for a video source-3/4 or VHS?

[ARC Tech-109]

Source is either 3/4U, BetaSP or 1"-C and I reference BB from a Tek 1474 NTSC generator via Kramer distro amp.

Both of the Nova TBCs were used in a dup house but I don't know what the master source was, I'm assuming it was VHS feeding VHS being it was for educational productions. They're functional to a point, not passing chroma at the moment and I want to make sure the switches are set before I dig deeper. my video feed for checkout is the demod out of my BVH-2000 and everyone is getting house BB.

[kf4rca]

Your playback machine should have an input for reference vertical coming from the TBC. (Some machines use input video for reference.) This phases the machine up to the TBC. Output phasing is for system timing (sync & subcarrier).

[ARC Tech-109]

The only machine I have that will use the ref is my BVH, all of my 3/4 decks lock to the house BB.

I also have two Microtime T100's and have never needed to use the V-pulse ref, they're older than many of our videokarma members but have never complained about the source. What I did do was feed the Nova 700 & 800 clean comp from my BVH internal TBC running a B&T tape and they would not pass chroma, the burst is there and they lock to the bouse BB, I also ran the V-pulse and got no chroma. Just to verify I then moved the T100 in place and connected everything the same and it passed chroma even without the V-pulse, I then moved to the tape demod (before internal TBC) and the T100 corrected just as it should. From there I moved to my ancient Sony VO-2860A and ran one of my old-old-old MTV captures from 1985 and got the same results. Everyone locked to the house BB the Microtime T100 was spot on but the Nova boxes only corrected the timing jitter. My monitors are Sony PVM-8044Q and a 1970 vintage Magnavox Astro sonic combo which has never been very forgiving. Both were rock solid with both the Nova and T100 except for the lack of chroma. When I flip the #6 dip I do get a phase shift in the output burst so I'm thinking there might be an internal issue with the Nova, considering the early 90's vintage they might have sour caps on the boards.

[kf4rca]

That's what I'm thinking. Were they sitting up for a long time before you got them? Surprised there is no documentation on the web.
I looked around for info on a CVS 504 TBC and could find nothing. Those were VERY popular in the 70's-80's. It was the first digital TBC (digitally controlled glass delay lines). Consolidated Video Systems won an emmy when they came out in the 70's.
Hope you didn't pay too much for them.

[ARC Tech-109]

I'd say they were last powered on during the last Bush administration. The dup house had several racks of Panasonic AG-6810's that were fed from an AG-7510 via TBC for the VHS side and two racks of VO-5600's feeding off either the SVHS, Sony 3/4U with it's own TBC or a BVH with the BVT-2000. The one Nova 800 was on the VHS side but I'm not sure about the Nova 700 and the Microtime T100's doing nothing... those are the ones that actually work.

I was involved with educational productions for a number of years working with a post house and providing them with technical support and the dup house was down the hall. Not the most elegant but it worked well. Over the years they moved to digital filling the racks with various servers pushing out the VTR's as needed so I got the last of the legacy video equipment. There were also two good VO-5850's in the pile and some other odds & ends but miss the boat on the manuals as all the file cabinets were emptied into a large gaylord and picked up by Shread-It before I was called.

I also missed out on the Microtime 2020. Ancient by all standards they were wonderful TBC's if you had the time to tailor them.

So in the present it looks like the T100's are the winners despite being a full decade older than the Nova units.

[ARC Tech-109]

So after further investigation I found the bottom of the chroma pot bused from an apparent hit... guess that would kill the color. Found some replacements at our local AxMan surplus store in St. Paul so for $2.99/ea everything is back to working normally.

Good units from what I can see, they only lock to an external BB ref and when I run my 3/4U thru on house BB it does what it should. I guess for a total of $15.00 with the gas used to ride the motorcycle that isn't a bad price to pay for two good digital TBCs.

[kf4rca]

Glad to hear that! If it worked before, it can work again! An old Chief Engineer told me that.
Are those 8 bit units? TBC's and Frame Sync's are either 8,9, or 10 bit. That has to do with quantization of the signal. Eight bit units chop the analog signal into 256 levels before dumping them into the memory. Nine bit units are 512 levels and 10 bit units 1024 levels. More bits require more memory but give a cleaner picture. The only 10 bit units I ever knew of were Sony and Tektronix. CNN had a Sony 10 bit unit when I was there. It took up about a foot of rack space.

[ARC Tech-109]

Honestly I'm not sure but I'd say they're 8-bit given the topology and limited memory space. The Microtime T100's have a single board of nothing but memory that measures a good 8x10 inches of 64k RAM plus a number of 128K EPROMS all dated late 1984 so I'm confident this is 8-bit technology most likely a four line time slice. The full frame Nova 800 has several meg of memory onboard with a number of processors so this one might be a 10-bit, hard to say without a manual or other documentation. If I get ambitious I might cross ref some of the IC's on the board to see what they're all about. There's two 128-pin quad pack processors running the show plus some EEPROM's and rows of what appears to be 640K RAM so I might make this one my primary TBC given it's capabilites.

I would imagine the Sony BVT-2000 external TBC for the type-c decks were all 10-bit given the capabilities of the recorder itself. I have the 4-card internal TBC in my BVH-2000 which is 8-lines but I have no idea at what depth, all the Sony IC's on the cards start with CX and that also happens to be the model prefix of consumer camcorders. Only thing I can confirm is it has plenty of memory to do what it needs to.

[ppppenguin]

Originally Posted by kf4rca

Are those 8 bit units? TBC's and Frame Sync's are either 8,9, or 10 bit. That has to do with quantization of the signal. Eight bit units chop the analog signal into 256 levels before dumping them into the memory. Nine bit units are 512 levels and 10 bit units 1024 levels. More bits require more memory but give a cleaner picture. The only 10 bit units I ever knew of were Sony and Tektronix. CNN had a Sony 10 bit unit when I was there. It took up about a foot of rack space.

The noise from just about any VT replay is sufficient to act as a dither signal for an 8 bit TBC. Adding extra bits then makes negligible difference.

A historical note on video analogue to digital conversion. This set the limit of what was feasible for digital video systems. High speed memory was expensive but much less of a problem. Converting video to digital used to be a very complex and critical board full of components. 8 bits was the limit of what could be done. Then TRW introduced the TDC1007. 20MHz sampling, 8 bit resolution. It was in a monstrous 64 pin ceramic DIL package and cost several hundred $$$. But it did the job in 1 chip and was used by Quantel and many others in pioneering digital video processing systems. It even won an Emmy award, such was its importance.

Knowing TRW's background in military and aerospace I wouldn't be surprised if it was first developed for military radar. The TV usage might well have been secondary.

[kf4rca]

Another important parameter is sampling. Early TBC's were 3fsc (10.7 mhz). This was determined by the Nyquist theorem. Later ones were 4fsc (14.31818 mhz). This required faster memory and reduced aliasing. Ten bit quantizing and 4fsc would later become the SMPTE standard.
Another piece of equipment I couldn't find any info on is the DPS Phaser1. It was made by Digital Processing Systems out of Toronto. It was a 9 bit unit, occupied about 10 inches of rack space and had two 6 inch fans on the rear. DPS was later bought out by SA (Scientific Atlanta). We liked it so much we bought another one when we put our second live truck in service. It used the Signetics 8x305 processor and had ECL memory. It was a workhorse. It would make chicken salad out of chicken (well, you know).
CNN had a Quantel. I thought it was over-priced at $250K. But they were the first with a DVE. But the Ampex ADO would become more popular as it was about $78K.

[kf4rca]

Do you remember ADDA? Did you hadda ADDA? It was a still store. It replaced slides and a film camera. It was 8 bit and 3fsc. But it did a lot. It used DEC drives. It was not only a still store, but also a 2 channel frame sync, and a (limited) DVE. Not sure who bought them out.

[ARC Tech-109]

So many of those orphans out there now since the digital revolution forced their obsolescence.

That being said I ran a VHS tape thru the Nova 800 full-frame and found the results rather impressive No it won't make chicken salad or even a chicken taco but it did clear up some of the timing and phasing issues well enough to recover the tape to another medium. The Nova 700 according to what I could find has a 32-line window and 8-bit depth, this one is also very sensitive to what's in the vertical interval and hangs up on the Macrovision 100% black/white stripes and freezes everything. The Microtime T100's seem to do the best all around despite their age and will clean up all that nonsense without complaining, they did their best with my VO-2860A which has its own built-in sync generator that subs in a clean pulse based on what's received from the tape but it's still subject to the timing errors. I can only lock the deck using ext BB but this doesn't seem to be a problem when everyone is dancing to the same tune.

[Electronic M]

Wish I could find a decent old broadcast TBC cheap. Seems whenever I find one it's north of $200.