>
>
>
> ----- Original Message -----
> From: "Dieter Doepfer" < hardware@... >
> To: "Bakis Sirros" < syrros@... >
> Sent: Monday, March 04, 2002 11:11 PM
> Subject: audio and trigger/gate signals
>
>
> > Hi Bakis,
> >
> > I'm still very busy because of the fair. But I
> have read some similar
> > questions/messages in the forum and I wanted to
> help a little.
> >
> > First of all one has to distinguish between
> "audio" and "digital" signals
> in the
> > A-100:
> >
> > Audio signals are (normally) AC coupled resp.
> symmetrical around zero. AC
> > coupled means that there is a capacitor in the
> signal path that removes DC
> > voltages and thus leads to a signal that is
> symmetrical around zero Volt.
> >
> > Digital signals (e.g. gate, trigger, clock) are
> signals that have normally
> 2
> > states: 0V and a fixed positive level (e.g. +5V or
> +12V, there is no
> functional
> > difference in the A-100 if the positive level is
> +5V, +7V, +8V or +12V as
> long
> > as the signal is used as a digital signal).
> >
> > Problems may occur if both types of signals are
> mixed. One example: the
> > sequencer A-155 has a clock input that (normally)
> has to be fed with a
> digital
> > signal (e.g. the clock output coming from the
> A-190 MIDI interface). But
> you may
> > connect the A-155 clock input to the (AC coupled)
> signal of a VCO A-110
> too. But
> > as the A-110 output and the A-155 are different
> types of signals
> (audio/digital)
> > the result cannot predicted in any case.
> >
> > Maybe we should introduce the following converter
> modules:
> > 1. analog -> digital module : i.e. a module that
> converts an AC coupled
> analog
> > signal at first into an analog signal without AC
> coupling followed by a
> > so-called comparator with adjustable threshold.
> Such a module would
> convert any
> > audio signal (e.g. from an VCO) into a digital one
> (e.g. 0/+5V) so that
> any
> > analog signal could be used to control digital
> inputs (e.g. clock of
> A-155,
> > trigger inputs of envelope generators, A-162,
> A-150/151, A-160/161 and so
> on).
> > 2. digital -> analog module: this could in the
> simplest case a capacitor
> that
> > converts any digital (e.g. 0/+5V or 0/+12V) signal
> into a AC coupled
> signal
> > symmetrical around zero V.
> >
> > I think the digital->analog module is not very
> important but the
> analog->digital
> > would help for a lot of "problems" mentioned in
> the newsgroup (especially
> for
> > controlling a digital clock/trigger/gate input
> from an ac coupled audio
> source).
> >
> > If necessary I will be able to explain this more
> detailed after the
> Frankfurt
> > fair.
> >
> > Best regards
> > Dieter Doepfer
> > Doepfer Musikelektronik GmbH
> > http://www.doepfer.de
> > email: hardware@...
> > Musikmesse Frankfurt March 13-17, 2002
> > Booth 6.0 C16 Hall 6
> >
> >
> >
>

=====
synthfreak(parallel worlds)
athens-greece
1 group owner-moderator

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