Re: Hornby Elite earns NMRA Conformance Warranrt

On Jan 30, 11:09 pm, "Wolf K." <wolf...@xxxxxxxxxxxx> wrote:
mumbles wrote:
The article actually reports on the effect of the layout itself on the
DCC signal, and specifically the occurrence of high-frequency "bounce"
or "ringing" around the transition from -15V to +15V. This transition
should be as sharp and smooth as possible, since the quality of the
signals received by the decoder chip depends on it. If the transition is
bad, the the information packet may not be read correctly.

If that's what the article said, then it sounds like a bias towards a
particular manufacturer whose decoders rely on edge recognition to
decode the packets. Packets can be decoded by regular sampling of the
DCC signal and this is much more immune to non-monotonic edges.

BTW, all five systems showed a degradation of the square wave towards a
sine wave form when a 1.A load was placed across the track. This implies
that boosters must be used.

What were the stated output limits of the systems being tested?


The terminator was placed at the end of the 66ft "single track line",
which was simulated electronically by using two "white boxes", each of
which had the same impedance characteristics as 33ft of track.

So nothing like a typical layout! On 66ft of track I would expect more
than one loco to be loading the signal, *and moving about* and
continually changing the load characteristics. All they've done is
look at a model of an empty layout. The above comment about waveforms
degrading towards sine waves shows why this doen't really tell us
anything useful. Did they account for multiple stub droppers feeding
the track from a bus in their impedance modelling?

Was there any mention of the importance of the wire sized used for
power distribution on large layouts.

Andrew
.

Relevant Pages

  • Re: David Bedard tutorial on Decoder Pro
    ... I didn't see that particular tutorial, but depending on exactly what you're trying to do, using DecoderPro without a layout connection isn't difficult. ... My guess is that you want DecoderPro to calculate various CV values that you then manually program into your decoder. ... You would follow those same steps, except that instead of writing from JMRI to the decoder, you would note the CV values on the CV tab as outlined above. ...
    (rec.models.railroad)
  • Re: Sound chips
    ... programing track but runs ok on the layout? ... them to reprogramme the decoder for you with a 2-digit address. ... Would the shop you mention not be willing to recode it for you? ...
    (uk.rec.models.rail)
  • Re: Sound chips
    ... My suggestion would be to find someone with a 'proper' DCC system and get ... them to reprogramme the decoder for you with a 2-digit address. ... think it had been done had it as 19, then the whole layout was changed ... programing track but working on the layout, ...
    (uk.rec.models.rail)
  • Re: Buying Broadway Limited??
    ... work even though I am running a Digitrax DCC system on my layout? ... The manufacturer recommends the DN143IP decoder (I'm planning to stick ...
    (rec.models.railroad)