Has anyone added a Master Clock to UpTone EtherREGEN Yet? It’s Insane!

@fsmithjack wouldn’t a sign wave be more precise than the clipped square wave? Once Hans Beekhauzen reviewed a master clock and preferred it over another because the reviewed clock was a full sin wave whereas the other less preferred one was a square wave? Please clarify. Thanks!

@fsmithjack Here is the answer to my question. It is from John Swenson from the Audiophile Style thread https://audiophilestyle.com/forums/topic/59419-master-clock-for-your-etherregen/page/2/:


”The specific reason: the clock input goes into a very low additive phase noise clock synthesizer and all its inputs are designed for square waves.

 

More general reason: all the digital circuits that use clocks actually use squarewaves so feeding a sinewave into the system either doesn't work at all or gives much higher jitter.

 

Technical explanation of the above: All clock receivers have some form of threshold circuit, it changes state when the clock voltage goes through that threshold voltage. NO signals are ever perfect, there is ALWAYS some form of amplitude noise on the signal, AND the receiver itself always has some form of fluctuations on the threshold voltage. So think of the clock signal rising towards the threshold, as it gets nearer to the threshold the amplitude of the noise comes into play, the threshold might get passed when the noise is at its peak or at its lowest point, or some place in between. This noise on the signal causes an uncertainty as to when it will actually get to the threshold, otherwise known as jitter. The faster the voltage rise of the signal the lower the time uncertainty for a given noise amplitude. Thus a square wave with very fast rise and fall times will have much lower jitter than a sinewave which has a much slower changing voltage. This is the reason a circuit designed for square wave input MAY still work with a sinewave, but the jitter in the circuit clocked by the signal will be higher.

 

There ARE some ways to convert sinewaves into square waves, but the simple ways actually increase the noise on the signal making the jitter even worse. There are some ways to do it well but they are complex and expensive and take a lot of power. Putting one of those on the clock input of the EtherREGEN would have at least doubled the cost of the device, not worth it in my opinion.

 

BTW these master clocks provide both sinewave and squarewave outputs for different applications. Radio systems that need a very stable frequency reference for running into mixers etc want a sinewave. Digital systems want a square wave. Either system CAN use the other type, but won't work nearly as well. So it is best to get the type of master clock that works well with what you want to use it for.

 I hope that makes some sense.

 John S.”