• Registered: 2007-05-02
  • Posts: 316

Topic: Word Clock Question

I have an ADI-8 which I use as the Word Clock Master for 2 Multifaces and a Digiface. Currently I'm connecting them using this topology:

ADI           Mulitface 1          Multiface 2             Digiface
V                  ^                        ^                          ^
=======<---->=======<---->========<---->====<75 ohm Terminator>

The cables are no more than 60 cm. However I find the BNC T-connectors I'm using aren't very good and if I knock on the rack where they're located I see the WC lights flash as the WC is lost and then reconnects. This rack has other gear that is handled often so this is getting to be annoying.

I have 3 affordable solutions:

1. Get better T-connectors.
2. Make a simple reliable version of the T-connectors: use a simple metal utility box, put 4 BNC jacks on it, body ground, centers internally connected, and connect the units to that.   
3. Build a simple clock distribution circuit using a video line amplifier.

(1)I'm pretty sure I can't find better connectors locally. (2) is the easiest solution but depends on whether the ADI-8 WC output can handle it. (3) I think I've found a chip that can do this simply (CLC1605) but it's always possible that my DIY might not be up to spec and makes the WC signal worse.

Opinions? TIA!

PC1 = HDSPe PCIe: DF-ADI-8 DS / HDSPe PCIe: MF2
MBP = HDSPe Expresscard: MF1

2 Reply by MC

  • MC
  • MC
  • Administrator
  • Offline
  • From: Germany/Thailand
  • Registered: 2007-04-06
  • Posts: 25,585

Re: Word Clock Question

1. Got the same problem regularly, makes me wonder why it seems to work everywhere else...

2. Wether this will work is somehow unpredictable. But I would try it, chances are that it will work. The problem with this 'parallel' splitting is that you can not terminate the ends. And then it is not clear how much ringing you get.

3. Try 2 first, if it doesn't work take the same housing to build the active version...

Regards
Matthias Carstens
RME

MC's Website

3 Reply by undertone (edited by undertone 2013-02-24 07:39:15)

  • Registered: 2007-05-02
  • Posts: 316

Re: Word Clock Question

WRT (2):

1. What I could do is use 5 BNC jacks and use a terminator on the fifth outer one. That would pretty much represent what's happening with the current setup. 

2. Would you know how much current the ADI-8 circuitry provides on the WC out?

Thanks for the advice!

PC1 = HDSPe PCIe: DF-ADI-8 DS / HDSPe PCIe: MF2
MBP = HDSPe Expresscard: MF1

4 Reply by MC

  • MC
  • MC
  • Administrator
  • Offline
  • From: Germany/Thailand
  • Registered: 2007-04-06
  • Posts: 25,585

Re: Word Clock Question

1. Not at all. It is about the cable length from the split point to the electronic receiver circuit. With T-connector - more or less zero. With your system - lots of centimeters.

2. I hate to repeat my manuals, sorry.

Regards
Matthias Carstens
RME

MC's Website

5 Reply by undertone (edited by undertone 2013-02-24 17:04:33)

  • Registered: 2007-05-02
  • Posts: 316

Re: Word Clock Question

MC wrote:

1. Not at all. It is about the cable length from the split point to the electronic receiver circuit. With T-connector - more or less zero. With your system - lots of centimeters.

Hmmm... I must of been out of spec from the beginning then because the way I connected things I have short BNC cables between the top of the T's to the devices (MF's and DF). I did this because I didn't have enough clearance in the rack to connect the T's directly to the WC inputs. Since this works (all show "Sync" on WC, when I don't knock the rack) then I suspect my "hack" will work. I'll let you know.

PC1 = HDSPe PCIe: DF-ADI-8 DS / HDSPe PCIe: MF2
MBP = HDSPe Expresscard: MF1
  • Registered: 2007-05-02
  • Posts: 316

Re: Word Clock Question

Here's a real case for the "KISS" principle: I went to take apart the current cabling and the BNC female on the the T-connector the cable coming out of the ADI was connected to just came apart! Had a spare T, replaced it, and PRESTO! Everything's rock solid again. Doh... fryingpan

PC1 = HDSPe PCIe: DF-ADI-8 DS / HDSPe PCIe: MF2
MBP = HDSPe Expresscard: MF1