Re: [time-nuts] ngTADD-1

2013-04-26 Thread Kevin Rosenberg
Thanks to all for the very helpful discussion. Appreciatively, Kevin On Apr 25, 2013, at 9:26 AM, Chris Albertson albertson.ch...@gmail.com wrote: The problem with analog 10MHz is the non-linear parts at each end of the fiber optic. It would be hard to get a nice sine wave at the output.

Re: [time-nuts] ngTADD-1

2013-04-25 Thread Hal Murray
ke...@rosenberg.net said: For 1ns jitter, do you have a recommendation of modulation (ASK/PSK?) and carrier frequency? All the digital communication over fiber that I'm familiar with is simple on-off baseband, no carrier. Digital geeks use encoding rather than modulation. One

Re: [time-nuts] ngTADD-1

2013-04-25 Thread Attila Kinali
On Wed, 24 Apr 2013 10:09:14 -0600 Kevin Rosenberg ke...@rosenberg.net wrote: On Apr 24, 2013, at 2:50 AM, Attila Kinali att...@kinali.ch wrote: [...] low jitter (sub 1ns rise/fall times). For the transmitters, if possible go for those with laser diodes and modulate them (ie no on-off

Re: [time-nuts] ngTADD-1

2013-04-25 Thread Lester Veenstra
To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] ngTADD-1 ke...@rosenberg.net said: For 1ns jitter, do you have a recommendation of modulation (ASK/PSK?) and carrier frequency? All the digital communication over fiber that I'm familiar with is simple on-off

Re: [time-nuts] ngTADD-1

2013-04-25 Thread Chris Albertson
The problem with analog 10MHz is the non-linear parts at each end of the fiber optic. It would be hard to get a nice sine wave at the output. I think if you have a requirement for very clean sine wave at the far end you'd best try to phase lock a local XO. Send a 10 MHz square wave down the

Re: [time-nuts] ngTADD-1

2013-04-24 Thread Kevin Rosenberg
On Apr 23, 2013, at 4:16 PM, Bob Camp li...@rtty.us wrote: There are optical links that are better than your typical opto coupler. I have not seen many that are good to -170 dbc. Rather than for a 10 MHz signal, I might prefer an optical link rather than differential for a PPS signal. Could

Re: [time-nuts] ngTADD-1

2013-04-24 Thread Attila Kinali
On Tue, 23 Apr 2013 22:08:28 -0600 Kevin Rosenberg ke...@rosenberg.net wrote: On Apr 23, 2013, at 4:16 PM, Bob Camp li...@rtty.us wrote: There are optical links that are better than your typical opto coupler. I have not seen many that are good to -170 dbc. Rather than for a 10 MHz

Re: [time-nuts] ngTADD-1

2013-04-24 Thread Bob Camp
Hi The stuff I've seen is aimed at the military market. It's in the don't even ask about the price category for home applications. It's also new enough that I doubt it's on the surplus market yet. I'd haunt the auction sites for a complete set of parts. You'll need both ends (tx and rx) *and*

Re: [time-nuts] ngTADD-1

2013-04-24 Thread Kevin Rosenberg
On Apr 24, 2013, at 2:50 AM, Attila Kinali att...@kinali.ch wrote: [...] low jitter (sub 1ns rise/fall times). For the transmitters, if possible go for those with laser diodes and modulate them (ie no on-off switching). This will give you jitter way below 1ns (sorry, don't know any hard

Re: [time-nuts] ngTADD-1

2013-04-23 Thread WB6BNQ
Hi Kevin, You could try TOSLINK fiber cable. Yes, it is not the best as far as fiber cable goes, but it seems to be a viable method. I got the idea from a Ham in, I believe, Colorado who was using it to isolate his 10 MHz for a project. If you are interested in viewing what the other guy

Re: [time-nuts] ngTADD-1

2013-04-23 Thread Bob Camp
Hi Like any design, the first question is - what's the goal? If you have enough RF running around, then shielding is well worth looking at. How much of the cable is in variable temperature space? If it's all indoors / heated living space, even tempo may not be a big deal. All that said, I'd

Re: [time-nuts] ngTADD-1

2013-04-23 Thread Kevin Rosenberg
On Apr 23, 2013, at 4:43 AM, Bob Camp li...@rtty.us wrote: Like any design, the first question is - what's the goal? My favorite first question, too. Move my most stable OXCO in the 1 Hz to 10 KHz range to the more stable environment, and maintain its phase noise of -100 dBc/Hz @ 1 Hz and -170

Re: [time-nuts] ngTADD-1

2013-04-23 Thread Kevin Rosenberg
On Apr 23, 2013, at 2:24 AM, WB6BNQ wb6...@cox.net wrote: I had to buy the three components at three different places. The TOSLINK receiver came from Mouse (p/n 757-TORX177F,T) and cost $1.31. The TOSLINK transmitter came from DIGIKEY (p/n 1080-1428-ND) and cost $0.866. At the time, for

Re: [time-nuts] ngTADD-1

2013-04-23 Thread Bob Camp
Hi If you are only worried into 1 Hz or even 0.1 Hz, temperature on the coax will not be a big issue. If you are trying to maintain 170 dbc at the far end of the wire, shielding and isolation will be a *big* issue. You may need some pretty fancy cable and magnetics to make that work…. Bob On

Re: [time-nuts] ngTADD-1

2013-04-23 Thread Bob Camp
Hi There are optical links that are better than your typical opto coupler. I have not seen many that are good to -170 dbc. Bob On Apr 23, 2013, at 3:58 PM, Kevin Rosenberg ke...@rosenberg.net wrote: On Apr 23, 2013, at 2:24 AM, WB6BNQ wb6...@cox.net wrote: I had to buy the three components

Re: [time-nuts] ngTADD-1

2013-04-23 Thread Kevin Rosenberg
On Apr 23, 2013, at 4:04 PM, Bob Camp li...@rtty.us wrote: If you are only worried into 1 Hz or even 0.1 Hz, temperature on the coax will not be a big issue. If you are trying to maintain 170 dbc at the far end of the wire, shielding and isolation will be a *big* issue. You may need some

[time-nuts] ngTADD-1

2013-04-22 Thread Kevin Rosenberg
I hope all is going well with your next-generation TADD-1. I'm thinking just thinking about putting a T-bolt disciplining a PRS-10 discipling a Soekris 4501. I was thinking a TADD-1 one would be nice for driving 10 MHz line to another room with the TADD-1 also providing galvanic isolation.

Re: [time-nuts] ngTADD-1

2013-04-22 Thread Bob Camp
Hi U, e. Even with all the mods, a 4501 is a fairly low resolution device. It's an amazing little box and I have several of them. Some (but not all) with the mods actually done correctly. You should be able to get away with a lot when driving one. Fancy distribution stuff is not

Re: [time-nuts] ngTADD-1

2013-04-22 Thread Kevin Rosenberg
On Apr 22, 2013, at 7:13 PM, Bob Camp li...@rtty.us wrote: U, e. Even with all the mods, a 4501 is a fairly low resolution device. It's an amazing little box and I have several of them. Some (but not all) with the mods actually done correctly. Ummm, apologies for the errant posting