# DCC Frequency



## rreiffer (Jan 14, 2009)

Hello again all,
I was wonder if anyone has an idea of the frequency range of DCC? If i do the math it runs from about 10KHz to 17KHz. (58 micro seconds as the narrowest pulse to 100 micro seconds as the widest).


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## krs (Feb 29, 2008)

Posted By rreiffer on 10 Mar 2011 06:59 PM 
Hello again all,
I was wonder if anyone has an idea of the frequency range of DCC? If i do the math it runs from about 10KHz to 17KHz. (58 micro seconds as the narrowest pulse to 100 micro seconds as the widest).


The frequency is half of what you posted.
You need to look at the complete cycle, one period of the "1" bit is 58+58 usec or a total duration of 116 usec, so the frequency is 8620 Hz and for the "0" bit it's nominal 5000 Hz.

Knut


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## George Schreyer (Jan 16, 2009)

Since the DCC signal, when it leaks to a sound system, is easily audible, the lowest frequency is lower than that.


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## rreiffer (Jan 14, 2009)

Knut, 
Duh, you are right! I forgot to devide by two!


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## MrDCC (Dec 27, 2007)

Remember 110 uS is the MINIMUM timing for zeros. Zero-stretching is used to move non-decoder-equipped locos by some DCC sets. They do this by "zero stretching" or making the length of zeros longer with one polarity than on the other, to move the locos.


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## rreiffer (Jan 14, 2009)

So the bottom line is that the frequency can be even lower. Thanks


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## Greg Elmassian (Jan 3, 2008)

Remember there are precious few DCC systems out there that still do zero stretching to run an unmodified loco on the tracks. 

If you are thinking of a high power booster, I would think there is zero market for a booster that handles this. 

Greg


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## krs (Feb 29, 2008)

Posted By Greg Elmassian on 12 Mar 2011 06:45 PM 
Remember there are precious few DCC systems out there that still do zero stretching to run an unmodified loco on the tracks. 


Not only that, you also need to have selected loco address "0" for "zero-stretching" to be active even if the system offers that feature.

With zero-stretching worst case frequency can go down to 100 Hz or so.


Maybe you could tell us why you are interested in the frequency of the DCC signal - is there anything particular you want to do?

Knut


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