Master Clock for your EtherREGEN

[JohnSwenson]

11 hours ago, dylanesque said:

Folks and gurus, thought experiment..

instead of using the minicircuits BLP-0.7 filter..

Any precedence of using a comparator circuit to convert Sine wave to Sq wave at the Clock input?

if so, how would one go about defining the parameters? Peak to peak amplitude.?

 

Comparators on their own are actually terrible at converting a sine to square. Any amplitude noise (AM) in the sine wave gets converted into jitter. The best way to do it is to filter out the noise first then feed it to the comparitor, BUT the comparitor itself generates jitter. The best way is a multistage circuit with low gain at each stage with filters before and inbetween. This is what we are going to do in the EtherrRegen 2.0.

 

John S.

[dylanesque]

12 hours ago, JohnSwenson said:

Comparators on their own are actually terrible at converting a sine to square. Any amplitude noise (AM) in the sine wave gets converted into jitter. The best way to do it is to filter out the noise first then feed it to the comparitor, BUT the comparitor itself generates jitter. The best way is a multistage circuit with low gain at each stage with filters before and inbetween. This is what we are going to do in the EtherrRegen 2.0.

 

John S.

Lovely! Thanks as always John S.

[dylanesque]

And as I recall, hence the ER2.0 will be waveform agnostic. Is this correct, that you can feed Sine wave without using the BLP filter? 

[Superdad]

38 minutes ago, dylanesque said:

And as I recall, hence the ER2.0 will be waveform agnostic.

EtherREGEN (“gen1”) already is. Both sine and square waves are fine with it. 
 

38 minutes ago, dylanesque said:

Is this correct, that you can feed Sine wave without using the BLP filter? 

You can with “gen1” as well. The Mini-Circuits low-pass filter just gets rid of any harmonics (either power supply spurie allowed by cheap clock boxes or stuff picked up by the clock cable) right before they hit the EtherREGEN. 
 

The state-of-the-art ultra low jitter sine>square wave converter chip and circuit that we will be introducing in EtherREGEN Gen2 will both negate the need for an external filter and will also enhance benefit of external clock use for sine wave clock owners. 
 

Use of a square wave clock will still be fine. 
And there is a chance that we may even run the internal Crystek CCHD-575 through the sine>square converter as well. Testing of that will be one of the final steps in development. 

[Markus8]

15 minutes ago, Superdad said:

And there is a chance that we may even run the internal Crystek CCHD-575 through the sine>square converter as well. Testing of that will be one of the final steps in development. 

What adventure would there be to expect? 

[kennyb123]

On 10/17/2023 at 9:54 AM, Superdad said:

The state-of-the-art ultra low jitter sine>square wave converter chip and circuit that we will be introducing in EtherREGEN Gen2 will both negate the need for an external filter and will also enhance benefit of external clock use for sine wave clock owners. 
 

Use of a square wave clock will still be fine

Will this circuit be bypassed if a square wave clock is used? 

[Johnnydev]

7 hours ago, kennyb123 said:

Will this circuit be bypassed if a square wave clock is used? 

square wave >square wave is not a problem, is it?

[doitttt]

I made it very simple

bought Mini-Circuits 141-12BM+ 12inch or 300mm

18pf good for sound with very low loss

silverclad beats cables over 1000 dollars

bought from mouser 40 dollars

as well as Mini-Circuits BLP-10.7+

Signal Conditioning Lumped LC Low Pass Filter, DC - 11 MHz, 50 ohms

60 dollars also at mouser

uses gustard u18 with cybershaft op20

how is the sound

better bass, midrange is more clear, top-class treble

much better sound and 3d

data sheet

https://www.mouser.dk/datasheet/2/1030/BLP_10_7_2b-3007309.pdf

https://www.mouser.dk/datasheet/2/1030/141_12BM_2b-1699951.pdf

[JohnSwenson]

On 10/18/2023 at 7:22 PM, kennyb123 said:

Will this circuit be bypassed if a square wave clock is used? 

The circuit has no way of knowing if the external clock is sine or square. It will work fine if you feed it a square, in that case it behaves as a very low phase noise single ended to differential buffer. So both can be used, the big advantage of this circuit is that a sine will be handled much better [then it is in EtherREGEN “gen1”].

 

John S.

[doitttt]

clock cable should best values in transfer
Insertion Loss 0.01 10mhz
Return Loss 60db 10mhz
signal reflection and VSWR ripple , as small as possible
Capacitance max 20pf
The cable must have a core of silver braid on copper
as short as possible 12 inch or 300mm
then 2 points are coax output from 10 mhz clock
for coaxing entrance 

 

[kennyb123]

11 hours ago, JohnSwenson said:

It will work fine if you feed it a square, in that case it behaves as a very low phase noise single ended to differential buffer. So both can be used, the big advantage of this circuit is that a sine will be handled much better [then it is in EtherREGEN “gen1”]

“Works fine” is a different standard than “optimal performance”.  Might you consider adding a switch that allows this circuit to be bypassed?  Everything tends to matter in this hobby, and while I can most certainly admire the inclusion of a feature that offers much better handling of sine wave clock signals, I would just hope that it doesn’t result in a backwards step for those using square wave clocks.  

[Superdad]

21 minutes ago, kennyb123 said:

I would just hope that it doesn’t result in a backwards step for those using square wave clocks.  

It won’t.

And there are so many other advancements in the EtherREGEN Gen2 which will elevate overall performance. I’m betting that it will outperform even just with its stock internal clock.

[kennyb123]

4 minutes ago, Superdad said:

It won’t.

And there are so many other advancements in the EtherREGEN Gen2 which will elevate overall performance. I’m betting that it will outperform even just with its stock internal clock.

I’m delighted to hear that.

[dylanesque]

14 minutes ago, kennyb123 said:

I’m delighted to hear that.

+1

[sandston]

.......yes but when can we get out little hands on it? 

[JohnSwenson]

4 hours ago, kennyb123 said:

“Works fine” is a different standard than “optimal performance”.  Might you consider adding a switch that allows this circuit to be bypassed?  Everything tends to matter in this hobby, and while I can most certainly admire the inclusion of a feature that offers much better handling of sine wave clock signals, I would just hope that it doesn’t result in a backwards step for those using square wave clocks.  

I'm sorry for the confusion, in the original ER the external clock goes through a single ended to differential converter builtin to the clock synthesizer, this WILL convert a sine into a square but not the best in the world. In the ER2.0 the external clock goes into the special very low noise sine to square converter which is a single ended to differential built in. I can't give you exact numbers as to which is better for a square wave since in the ER1.0 it is internal to another chip. Given the performances of the converter circuit and the numbers of single ended to differential converters made by the same company that makes the original clock synthesizer my guess is that the new method will have about the same for sine and square. Compared to the ER1.0 implementation the square will be slightly better and the difference for the sine will be a little bit more.

 

Note none of these are big differences! Maybe along the line of 1-2 dBc at 10Hz offset. Because of the difference in architecture measuring differences between 1.0 and 2.0 can only be done at the output of the clock synthesizer and we know the new clock synthesizer is quite a bit better than the old one, so no matter which clock you use (internal, external sine or square) it is going to be better than what we had in the ER1.0.

 

John S.

[kennyb123]

50 minutes ago, JohnSwenson said:

Compared to the ER1.0 implementation the square will be slightly better and the difference for the sine will be a little bit more.

 

Woo hoo.  Thanks for investing your energies towards improving things even further.

[Superdad]

1 hour ago, kennyb123 said:

Woo hoo.  Thanks for investing your energies towards improving things even further.

Always! 

And as ever, there do not seem to be any other firms in our market attempting anything near the sophistication of what goes into EtherREGEN.

Nobody else is using differential clocking, active differential isolators, or differential flip-flops.

And with the new EtherREGEN Gen2 will come brand new, tiny, low power, low jitter PHY chips (which we know for certain that NOBODY else is using since we got in on those with the manufacturer at beta), a much newer main switch chip, one less transceiver in the path to the ‘B’ side (since we will putting SGMII directly across the “moat”), lower jitter clock synth system, and the aforementioned extraordinary sine>square buffer.

 

Users will also enjoy Gigabit capability on thr ‘B’ side, and most likely an SFP cage on the ‘B’ side (but only one ‘B’-side port—the RJ45 or the SFP—can be active at a time; the unit will sense at power-on if active connection is present at the SFP cage).

 

And as always, we are about the only firm willing to show all our work and explain the technical details behind our designs. No vague “marketing-speak” BS from us. 
While I know it disappoints some to not have EtherREGEN in fancy milled casework, we’d rather put the $$ into the advanced logic and power supply networks on our 6-layer board—while still charging well under $1,000 and under uninspiring other switches out there. 

[doitttt]

Does Capacitance pf have anything to say in the clock cable
the shorter cable has less Capacitance maybe down 15pf
for 30cm or 300mm cable

[Jakenz]

3 hours ago, doitttt said:

Does Capacitance pf have anything to say in the clock cable
the shorter cable has less Capacitance maybe down 15pf
for 30cm or 300mm cable

Interestingly Cybershaft, at the bottom of the silver cable page you linked to, say cable  capacitance and length is a factor for square wave, but not sine. Presumably this is based on their experience measuring phase noise across a variety of equipment & cable designs and combinations.

[JohnSwenson]

8 hours ago, Jakenz said:

Interestingly Cybershaft, at the bottom of the silver cable page you linked to, say cable  capacitance and length is a factor for square wave, but not sine. Presumably this is based on their experience measuring phase noise across a variety of equipment & cable designs and combinations.

This is sort of correct, the capacitance has very little to do with a sine wave. The length, sort of. A long cable can pick up more noise which is far more problematic with a sine. So long cables should be very well shielded. So for example the difference in length for a cheap not well shielded cable can actually make a difference. Thus if you want to go a long distance use a very well shielded cable.

 

Even with a square the capacitance per se is not important, it is the capacitance AND the inductance that make up the characteristic impedance that matters. So for a square just focus on the characteristic impedance, if that is correct, the capacitance will be what it needs to be, don't worry about low or high capacitance numbers.

 

John S.

[doitttt]

thanks JohnSwenson

info the double sheild will be best on because of the noise
maybe 4 double sheild would be extra good
maybe this cable

https://www.highendcableshop.eu/product/tubulus-concentus-bnc-clock-cable

[JohnSwenson]

18 hours ago, doitttt said:

thanks JohnSwenson

info the double sheild will be best on because of the noise
maybe 4 double sheild would be extra good
maybe this cable

https://www.highendcableshop.eu/product/tubulus-concentus-bnc-clock-cable

This cable is specifically designed for square waves, most of it's "special sauce" is irrelevant for sine waves. Of course you can buy it if you want, but you are spending money on stuff you don't need. For sine wave the best cables you can get are are the "semi-rigid" type. A custom semi rigid cable from Pasternack or other RF companies will be about as good as you can get. Cybershaft also sells such a cable for about a third of the price of this cable. 

 

If you do have a square wave that is a different story, then a cable such as this MAY be appropriate. I don't know how good this really is. There are some manufacturers that go with all the fancy stuff, then get the characteristic impedance wrong or use the wrong connector. If you do this all the fancy stuff doesn't do any good. If I was going to spend this kind of money on a clock cable I would want an interdependent measurement of the characteristic impedance of the cable and connector. Particularly if it is supposed to be a 75 ohm cable. You will not believe how many times I have seen 75 ohm cables with 50 ohm connectors! 

 

John S.

[sbilotta]

1 hour ago, JohnSwenson said:

For sine wave the best cables you can get are are the "semi-rigid" type. A custom semi rigid cable from Pasternack

 

Something like this:

 

[realfx]

@JohnSwenson Do you think using this Cybershaft 50ohm matching adapter https://cybershaft.shop/products/50-ohm-matching-adapter to connect a 10Mhz square wave 50ohm clock signal with a high quality (Huber+Suhner) 50ohm cable to the 75ohm input of a Mutec MC3+ USB will be ok? Or will the square wave signal be truncated?

The Mutec has the possibility to leave the clock input without the internal 75ohm load so it´s possible to use a T-BNC with a terminating 50ohm load plugged to it but the Mutec input female BNC will still be 75ohm so, which do you think would be the right way to connect the 10Mhz square wave 50ohm signal to the Mutec? With the Cybershaft 50ohm matching adapter or with a T-BNC with a 50ohm terminating load in the Mutec clock input while setting the clock input load of the Mutec to "no load"?

 

Thanks!