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I am currently doing some research on DCC and would be starting to
build a DCC receiver according to NMRA stardards in due time.

At the very moment, I would like to extract the signal waveforms from
the tracks. Any ideas how I should go about doing that.

Is there a standard voltage, current and frequency from the control
station?

Aaron

Aaron,

If you are looking to decode the packets, then try this: www.dcctester.com
which will read and decode all the packets. You can display the packets on a
built-in LCD, on a PC using Hyper Terminal, or using Stefan Trachsler's
LocoChecker here:


Hope this helps!

Bob Scheffler

Dear Bob,

The device you introduce to me is very interesting, but I am looking
for something that can show me the waveform from the rails.

I have the thought to build the device as part of my project, so was
wondering if you know how to separate the frequencies from the rails.

The picture I have in mind is something like a 'microfilter (for the
telephone line)' where the output will be to a oscillator to view
the waveforms.

I havn't buy my own set of tracks yet, therefore I would like to
know if whether there are standard voltage, current and frequency
from the rails, or is it up to individual product in the market.

All contributions are welcome

Aaron


--- In WiringForDCC@..., "Robert Scheffler" <bob@p...>
wrote:

Aaron,

If you are looking to decode the packets, then try this:

www.dcctester.com

which will read and decode all the packets. You can display the

packets on a

built-in LCD, on a PC using Hyper Terminal, or using Stefan

Trachsler's

LocoChecker here:


Hope this helps!

Bob Scheffler

Aaron,

You have some reading to do!
The standards page:


Start with the electrical spec:


Then read the packet format:



To greatly simplify, DCC is a square wave that has 2 distinct time periods,
58uS and 116uS. If the square wave is 58uS in period, it indicates a '1' and
if it is 116uS (or longer) it indicates a '0'. The amplitude of the waveform
is typically 12V-18V depending on the scale of railroad, and how much motor
voltage you want present on the rails. Because it is a square wave, you can
use a simple bridge rectifier to obtain DC power from the track without
large capacitors. This is important because there isn't room inside a loco
for large capacitors. With this DC power extracted from the rails, you can
power your decoder CPU, and let it watch the waveform to determine the bits,
and packets. If you are controlling a motor, such as a loco, you would then
use this DC power extracted from the rails and use PWM to speed control the
loco motor.

There are more details, but I hope that description helps get your head
around the concept.

Bob Scheffler
~~~~~~~~~~~~~~
www.pricom.com

Is there a standard voltage, current and frequency from the control
station?

Yes...thats what DCC standards are all about. See .

DonV