Horozontial Sync?

[wezard 0]

I've been away from CCTV for about 18 years, used to do a lot of really high end stuff. The only available 12Vdc were toys. We often had to use cameras from different manufactures and/or power cameras from different sources. It was necessary to sync the cameras, all real cameras had sync adjust pots. Now I'm putting some cameras in my house, and seeing lots of DC cameras with internal sync, and a lot of the AC cams have internal sync. How do you sync these things so the switcher or recorder know when to switch, and so monitors don't roll when switching?

I've searched here and elsewhere, and am not finding anybody talking about it.

[Soundy 1]

Nobody's talking about it because it's not a problem anymore

[wezard 0]

Why is not a problem any more? Does every camera on the market magically switch frames at exactly the same time?

[Soundy 1]

I don't what's changed between then and now... I did take a bit of broadcast video training as part of an audio production program back in the late 80s and I know using genlock to sync was a big deal, but mainly to avoid the "flipping" problem you'd get switching from one camera to the next. The only thing that does that now on CCTV would be a low-end video switcher, and if memory serves, the last time I used one, it did still do that... but those sorts of switches are pretty much obsolete and I haven't seen on in use in years. DVRs, multiplexers, quad processors and the like, all digitize and process the video, so sync issues really don't exist anymore.

[wezard 0]

So the cameras are still changing frames at different times, the switching equipment just waits till it sees a pedestal before it starts recording or displaying again. You're loosing some information there, but I guess not enough to worry about, though back in the day, a few of our clients would throw a fit if they knew they were missing a frame between cameras.

Guess that also means the techs don't have to carry around scopes any more?

[Soundy 1]

I'd love to have a scope "just because"... might be nice sometimes for troubleshooting really weird cabling problems... but no, I've never needed one.

 

You're not losing frames, because like I say, aside from a very few, ancient input-switching units, each camera is being input and processed separately. A DVR is recording every camera individually, so technically everything is buffered anyway.

[wezard 0]

I'm hearing really good things about the Chinese digital scopes, Rigol, (not 100% sure of the spelling) in particular. You can get a new 100Mhz dual trace for less than $500.

Then there a couple of good USB scopes that plug into a laptop, clunky hard to use interface, but the data is supposed to be accurate, less than $300 for 100Mhz dual.

I've been doing industrial automation and control for quite a while now, I find my old basic model 50Mhz dual to be helpful for checking noise on lines and VFD outputs. A 4 channel would be really nice, so I could see all 3 phases at the same time, but I cant justify the cost, yet.

 

Back to Horz sync, I did not know that all inputs were being procesed and recorded independently, apparently most of my knowledge and skills are obsolete. Need a camera re-tubed and tuned? I can do that.

Mike

[tomcctv 190]

Back to Horz sync, I did not know that all inputs were being procesed and recorded independently, apparently most of my knowledge and skills are obsolete. Need a camera re-tubed and tuned? I can do that.

 

 

 

showing your age now........ thats the old videcom days the time of the old solder BNC or the niddle insert BNC. still have a few packs of them here

[wezard 0]

I've soldered my share, then we went with 2 piece crimp on, hated those, I'd rather solder, then the one piece crimp on, loved those. I still call Burle RCA half the time, is Burle still in business?

 

Any opinions on Nuvico DVR'rs, the EV8000 in particular? Already bought it, so I'm gonna use it anyway, but nice to have input.

Mike

[Soundy 1]

I'm hearing really good things about the Chinese digital scopes, Rigol, (not 100% sure of the spelling) in particular. You can get a new 100Mhz dual trace for less than $500.

Then there a couple of good USB scopes that plug into a laptop, clunky hard to use interface, but the data is supposed to be accurate, less than $300 for 100Mhz dual.

I've been doing industrial automation and control for quite a while now, I find my old basic model 50Mhz dual to be helpful for checking noise on lines and VFD outputs. A 4 channel would be really nice, so I could see all 3 phases at the same time, but I cant justify the cost, yet.

Check out some sites like DealExtreme:

 

- Pocket 4-channel digital oscilloscope for common electronic engineering tasks

- 3" LCD display

- Vertical solution: 8-bit

- Storage: single channel 8K, 4-channel 4 x 4K

- Package included:

- 1 x Oscilloscope device

- 1 x Probe

- 1 x USB cable

- 1 x Set of rubber rings

 

Under $200 Doesn't say what its range is or anything, but these things are rapidly getting cheaper and smaller - this one's about the size of your average smartphone.

 

Here's a little fancier one for a tad over $300, similar form factor to most pro-grade multimeters:

 

- Model: UTD1025CL

- Color: Red + Grey

- 3.5" 64K color TFT LCD

- Channel number: 1

- Bandwidth: 25MHz

- Rise Time: 14ns

- Sample Rate: 200MS/s

- Vertical Sensitivity: 5mV/div-20V/div

- Memory Depth: 12kpts

- Scanning Speed: 10ns/div-50s/div

- Trigger Type: Edge,Pulse,Video,Alternate

- Storage: Bitmap,Waveform,Set

- Interface: Mini USB

- Multimeter:

- DC Voltage: 400mV/4V/40V/400V ±(1%+5)

- AC Voltage: 400mV/4V/40V/400V ±(1.2%+5)

- DC Current: 400uA/4000uA ±(1.2%+5), 40mA/4000mA ±(1%+5), 10A ±(1.5%+5)

- AC Current: 400uA/4000uA ±(2%+5), 40mA/4000mA ±(1.5%+5), 10A ±(5%+5)

- Resistance: 400 ohm/4K ohm/40K ohm/400K ohm/4M ohm ±(1.2%+5), 40.00M ohm ±(1.5%+5)

- Capacitance: 51.2nF/512nF/5.12uF/51.2uF/100uF ±(3%+5)

- Built-in rechargeable 7.4V 3600mAh lithium battery

- Working time: not less than 8 hours

- Accessories:

- 1 x 100~240V 50/60HZ 1.5A power adapter (325cm cable)

- 2 x Test Leads (111cm)

- 2 x Sensors (1:1 / 10:1)

- 1 x 10A splitter

- 1 x Carrying pouch

- 1 x USB connecting cable (150cm)

- 1 x Software CD

- 1 x English Manual

 

Specifications

Item: UTD1025CL 3.5" LCD Handheld Digital Oscilloscope

Dimensions: 7.72 in x 4.33 in x 1.77 in (19.6 cm x 11.0 cm x 4.5 cm)

Weight: 82.05 oz (2326 g)

[Stanislav 0]

Not in all devices all inputs have independent ADCs.

Some frame grabber chips have a multiplexer (simple switch) between several inputs and one shared ADC. This scheme limits the maximal frame rate from multiplexed non-synchronized cameras because the ADC must wait for the moment of starting frame from the next multiplexed camera.

 

That is the reason of difference between max frame rate of "one camera for one chip" and "several multiplexed cameras for one chip".

For example for one camera - 25fps, but for several cameras in sum - 12.5fps.

 

I tested a PC-based video recording system several years ago. The system has a mode which allows to considerably increase number of frames from several multiplexed cameras. But in this mode the system became sensitive to sync. When I connected synchronized cameras - the images were good, but with non-synchronized cameras their images were unstable on vertical.

[wezard 0]

Guess I should recheck the specs on my DVR, (Nuvico EV-8000), 4 of the cams are new and the same, gonna run them on single AC supply, they should be in sync. the 5th is a brand new 12 year old high end Sony box cam with full sync adjustment, I'll sync it even if I don't really have to. The 6th is installed and blew me away, (it's DC and can't be synced). It's a tiny board cam in metal box with mount with cheap looking fixed lens. Not sure what the rules are here, so I'll put the info on a single line in case the moderators want to remove it.

 

SecurityCamera2000.com #PZ047-N with 6mm about $65.00

 

It's inside the house, looking through the carport door, which is windows from the waist up, looking east, (into rising sun). So about 60% of the frame is natural changing back light. It took me a while to figure out the onboard controls and get it dialed in, but it works great. I've seen better shots, but this is good all day and night, without IR illum. Back in my day it would have cost well over $2,000.00 to even get close to this good, and it would have been BIG.

 

If you enter through this door, you would have the side end of a cabinet wall directly in front of you at about 5', bear left into kitchen, right into living room. there is a bulletin board on the wall, I mounted the cam above the board, almost not noticeable, below the board is the alarm control. I got a 7" LCD, thin, designed for the back of a headrest in a car, and flush mounted it right beside the alarm panel. It was about $65.00. This is THE door that bad guys will peek into before entering, so the first thing they will see is an alarm panel and a live picture of themselves. I'm pretty sure this will convince them to go on down the road, maybe even pick another subdivision.

 

Given the cost of these little LCD's, and the ease with which they can be flush mounted, I'm thinking of putting one at the end of the hall by the bedrooms, right beside the thermostat, and letting it show all cams. That way we can see without being seen, or going down to the basement where the head end is.

 

Not sure how long these LCD's will last running 24/7, but for the cost, I can afford to change them every year.