MOTM

On the VC Pulse Divider from Serge, there is an output called 'STEPPED'. I'm
am pretty sure
how they did it (not seeing the circuit).

The output is a stair-cased, positive-going sawtooth. The sawtooth is
generated by a 5-bit
counter, that is *clocked* by the input pulses and *reset* by the
divide-by-N pulse.
The output counter bits feed a 5-bit DAC.

So, here are some interesting things about this sawtooth:

a) for a fixed frequency in, the *amplitude* is inversly proportional to the
divide ratio. Think
about it: the longer you count, the higher the amplitude.

b) of course, for a fixed input frequency, the *output* frequency is
proportional to the divide
ratio. If you input 4Khz and divide by 8, you get out a 500Hz sawtooth with
8 steps. Assuming
a -5V to +5V output scaling (like all the other signal generators), we have
10V/32 steps = 312mv/step. So for 8 steps = -5V to -2.5V sawtooth.

For straining the brain more: this acts as a low-pass filter! Since the
divide ratio is a control
voltage, then if the input is fixed (say 2Khz) then as the divisor is swept
from 32 to 1 the
amplitude AND frequency change. But, the amplitude drops off at higher
frequency outputs
since the counter is reset faster and faster.

Of course, if you fix the divide ratio and sweep the input, the amplitude of
the sawtooth is *constant*
at the divide ratio X 312mv.

Will add $15 to the cost of the module. Discuss!

Paul S.

I see very little to discuss.  This is a very cool feature and well worth the $15. 
At the very least, it is good to get some other waveform out of the pulse divider
than square wave!  Please add this feature.

Eric

--- Paul Schreiber <synth1@...> wrote:
> On the VC Pulse Divider from Serge, there is an output called 'STEPPED'. I'm
> am pretty sure
> how they did it (not seeing the circuit).
> 
> The output is a stair-cased, positive-going sawtooth. The sawtooth is
> generated by a 5-bit
> counter, that is *clocked* by the input pulses and *reset* by the
> divide-by-N pulse.
> The output counter bits feed a 5-bit DAC.
> 
> So, here are some interesting things about this sawtooth:
> 
> a) for a fixed frequency in, the *amplitude* is inversly proportional to the
> divide ratio. Think
> about it: the longer you count, the higher the amplitude.
> 
> b) of course, for a fixed input frequency, the *output* frequency is
> proportional to the divide
> ratio. If you input 4Khz and divide by 8, you get out a 500Hz sawtooth with
> 8 steps. Assuming
> a -5V to +5V output scaling (like all the other signal generators), we have
> 10V/32 steps = 312mv/step. So for 8 steps = -5V to -2.5V sawtooth.
> 
> For straining the brain more: this acts as a low-pass filter! Since the
> divide ratio is a control
> voltage, then if the input is fixed (say 2Khz) then as the divisor is swept
> from 32 to 1 the
> amplitude AND frequency change. But, the amplitude drops off at higher
> frequency outputs
> since the counter is reset faster and faster.
> 
> Of course, if you fix the divide ratio and sweep the input, the amplitude of
> the sawtooth is *constant*
> at the divide ratio X 312mv.
> 
> Will add $15 to the cost of the module. Discuss!
> 
> Paul S.
> 
> 
> 
> 
> 
> 


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I don't use this output very much, but when I do, I use it more often as a CV 
source than a (audio) signal source. It's good for weird glissandi kinda 
things -- I always thought the output was a whole tone scale (into a 1V/oct 
input), but I never use it in a tempered music setting, just more atonal 
stuff. I should point out that Serge used 0-5V signals, so the steps are half 
what the MOTM would be. 

I find this to be a nice feature when you want another varying voltage, and I 
think it's well worth the $15. It is nice to have for those very electronic 
"everything modulate everything else" patches.

JB


In a message dated 10/14/2000 7:24:20 PM, synth1@... writes:

>On the VC Pulse Divider from Serge, there is an output called 'STEPPED'.
>I'm
>am pretty sure
>how they did it (not seeing the circuit).
>
>The output is a stair-cased, positive-going sawtooth. The sawtooth is
>generated by a 5-bit
>counter, that is *clocked* by the input pulses and *reset* by the
>divide-by-N pulse.
>The output counter bits feed a 5-bit DAC.
>
>So, here are some interesting things about this sawtooth:
>
>a) for a fixed frequency in, the *amplitude* is inversly proportional to
>the
>divide ratio. Think
>about it: the longer you count, the higher the amplitude.
>
>b) of course, for a fixed input frequency, the *output* frequency is
>proportional to the divide
>ratio. If you input 4Khz and divide by 8, you get out a 500Hz sawtooth
>with
>8 steps. Assuming
>a -5V to +5V output scaling (like all the other signal generators), we
>have
>10V/32 steps = 312mv/step. So for 8 steps = -5V to -2.5V sawtooth.
>
>For straining the brain more: this acts as a low-pass filter! Since the
>divide ratio is a control
>voltage, then if the input is fixed (say 2Khz) then as the divisor is swept
>from 32 to 1 the
>amplitude AND frequency change. But, the amplitude drops off at higher
>frequency outputs
>since the counter is reset faster and faster.
>
>Of course, if you fix the divide ratio and sweep the input, the amplitude
>of
>the sawtooth is *constant*
>at the divide ratio X 312mv.
>
>Will add $15 to the cost of the module. Discuss!

On Sat, 14 Oct 2000, Paul Schreiber wrote:

> Will add $15 to the cost of the module. Discuss!

  The VCPD already had the 4-bit RAMP output; are we talking about
changing that around a bit?  It could probably be done in the code.

Crow

/**/

> On the VC Pulse Divider from Serge, there is an output called 'STEPPED'.
I'm
> am pretty sure
> how they did it (not seeing the circuit).

I thought I was pretty sure how they did it, too, but I may me wrong:
I thought they used a charge pump like that NS app note for the
LM3900. I mean they might have used a counter, but seeing Serge's
general fondness of the 3900, I'd be surprised if he would not have
done it with that single chip. (Anybody knows for sure ?)

And yes, bringing out the ramp would be useful. (I have not done it
on my version, but I wished I had.)

JH.



>
> The output is a stair-cased, positive-going sawtooth. The sawtooth is
> generated by a 5-bit
> counter, that is *clocked* by the input pulses and *reset* by the
> divide-by-N pulse.
> The output counter bits feed a 5-bit DAC.
>
> So, here are some interesting things about this sawtooth:
>
> a) for a fixed frequency in, the *amplitude* is inversly proportional to
the
> divide ratio. Think
> about it: the longer you count, the higher the amplitude.
>
> b) of course, for a fixed input frequency, the *output* frequency is
> proportional to the divide
> ratio. If you input 4Khz and divide by 8, you get out a 500Hz sawtooth
with
> 8 steps. Assuming
> a -5V to +5V output scaling (like all the other signal generators), we
have
> 10V/32 steps = 312mv/step. So for 8 steps = -5V to -2.5V sawtooth.
>
> For straining the brain more: this acts as a low-pass filter! Since the
> divide ratio is a control
> voltage, then if the input is fixed (say 2Khz) then as the divisor is
swept
> from 32 to 1 the
> amplitude AND frequency change. But, the amplitude drops off at higher
> frequency outputs
> since the counter is reset faster and faster.
>
> Of course, if you fix the divide ratio and sweep the input, the amplitude
of

> the sawtooth is *constant*
> at the divide ratio X 312mv.
>
> Will add $15 to the cost of the module. Discuss!
>
> Paul S.
>
>
>
>
>
>

In a message dated 00-10-14 22:24:18 EDT, you write:

<< Will add $15 to the cost of the module. Discuss!
  >>


paul,
just my 2 cents worth but i`d say "yes" include it.
best,
dave v.

although I still dont know what Ill use this module for, Im all for adding as
many options, including led's : )  as possible./
Jim

jhaible@... wrote:

> > On the VC Pulse Divider from Serge, there is an output called 'STEPPED'.
> I'm
> > am pretty sure
> > how they did it (not seeing the circuit).
>
> I thought I was pretty sure how they did it, too, but I may me wrong:
> I thought they used a charge pump like that NS app note for the
> LM3900. I mean they might have used a counter, but seeing Serge's
> general fondness of the 3900, I'd be surprised if he would not have
> done it with that single chip. (Anybody knows for sure ?)
>
> And yes, bringing out the ramp would be useful. (I have not done it
> on my version, but I wished I had.)
>
> JH.
>
> >
> > The output is a stair-cased, positive-going sawtooth. The sawtooth is
> > generated by a 5-bit
> > counter, that is *clocked* by the input pulses and *reset* by the
> > divide-by-N pulse.
> > The output counter bits feed a 5-bit DAC.
> >
> > So, here are some interesting things about this sawtooth:
> >
> > a) for a fixed frequency in, the *amplitude* is inversly proportional to
> the
> > divide ratio. Think
> > about it: the longer you count, the higher the amplitude.
> >
> > b) of course, for a fixed input frequency, the *output* frequency is
> > proportional to the divide
> > ratio. If you input 4Khz and divide by 8, you get out a 500Hz sawtooth
> with
> > 8 steps. Assuming
> > a -5V to +5V output scaling (like all the other signal generators), we
> have
> > 10V/32 steps = 312mv/step. So for 8 steps = -5V to -2.5V sawtooth.
> >
> > For straining the brain more: this acts as a low-pass filter! Since the
> > divide ratio is a control
> > voltage, then if the input is fixed (say 2Khz) then as the divisor is
> swept
> > from 32 to 1 the
> > amplitude AND frequency change. But, the amplitude drops off at higher
> > frequency outputs
> > since the counter is reset faster and faster.
> >
> > Of course, if you fix the divide ratio and sweep the input, the amplitude
> of
> > the sawtooth is *constant*
> > at the divide ratio X 312mv.
> >
> > Will add $15 to the cost of the module. Discuss!
> >
> > Paul S.
> >
> >
> >
> >
> >
> >
>

I'd say it's worth the $15.

dh

At 09:32 PM 10/14/00 -0500, you wrote:
>Will add $15 to the cost of the module. Discuss!

Not that I'll change the consensus so far, but the more versatile the
module the better.  For $15 more, please add it.

I would personally be willing to pay $15 for something like this.
Larry H

Hi .
i think its a cool feture as it can save a LFO use as a arprigator,
by quantized the output in sync with the input clock you can
get wiled sequencing.

thanx
Gur Milstein 

At 21:32 14/10/00 -0500, you wrote:

>On the VC Pulse Divider from Serge, there is an output called 'STEPPED'. I'm
>am pretty sure
>how they did it (not seeing the circuit).

I studied the LM3900 app notes a year or two ago, and came to the same conclusion about the Serge pulse divider. I'm as sure as someone who has never seen the insides of a Serge module can be that it's using a purely analog LM3900 staircase generator to do the dividing. And part of me respects the pure-analog-ness of that solution. ;-)

- hdan

-----Original Message-----
From: jhaible@... [mailto:jhaible@...]
Sent: Sunday, October 15, 2000 4:23 AM
To: motm@...m
Subject: Re: [motm] Is this useful?

> On the VC Pulse Divider from Serge, there is an output called 'STEPPED'.
I'm
> am pretty sure
> how they did it (not seeing the circuit).

I thought I was pretty sure how they did it, too, but I may me wrong:
I thought they used a charge pump like that NS app note for the
LM3900. I mean they might have used a counter, but seeing Serge's
general fondness of the 3900, I'd be surprised if he would not have
done it with that single chip. (Anybody knows for sure ?)

And yes, bringing out the ramp would be useful. (I have not done it
on my version, but I wished I had.)

JH.

>
> The output is a stair-cased, positive-going sawtooth. The sawtooth is
> generated by a 5-bit
> counter, that is *clocked* by the input pulses and *reset* by the
> divide-by-N pulse.
> The output counter bits feed a 5-bit DAC.
>
> So, here are some interesting things about this sawtooth:
>
> a) for a fixed frequency in, the *amplitude* is inversly proportional to
the
> divide ratio. Think
> about it: the longer you count, the higher the amplitude.
>
> b) of course, for a fixed input frequency, the *output* frequency is
> proportional to the divide
> ratio. If you input 4Khz and divide by 8, you get out a 500Hz sawtooth
with
> 8 steps. Assuming
> a -5V to +5V output scaling (like all the other signal generators), we
have
> 10V/32 steps = 312mv/step. So for 8 steps = -5V to -2.5V sawtooth.
>
> For straining the brain more: this acts as a low-pass filter! Since the
> divide ratio is a control
> voltage, then if the input is fixed (say 2Khz) then as the divisor is
swept
> from 32 to 1 the
> amplitude AND frequency change. But, the amplitude drops off at higher
> frequency outputs
> since the counter is reset faster and faster.
>
> Of course, if you fix the divide ratio and sweep the input, the amplitude
of
> the sawtooth is *constant*
> at the divide ratio X 312mv.
>
> Will add $15 to the cost of the module. Discuss!
>
> Paul S.
>
>
>;
>
>
>

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> -----Original Message-----
> From:	Paul Schreiber [SMTP:synth1@...]
> Sent:	Saturday, October 14, 2000 7:32 PM
> To:	MOTM listserv
> Subject:	[motm] Is this useful?
> 
> On the VC Pulse Divider from Serge, there is an output called 'STEPPED'.
> I'm
> am pretty sure
> how they did it (not seeing the circuit).
> 
> The output is a stair-cased, positive-going sawtooth. The sawtooth is
> generated by a 5-bit
> counter, that is *clocked* by the input pulses and *reset* by the
> divide-by-N pulse.
> The output counter bits feed a 5-bit DAC.
> 
> So, here are some interesting things about this sawtooth:
> 
> a) for a fixed frequency in, the *amplitude* is inversly proportional to
> the
> divide ratio. Think
> about it: the longer you count, the higher the amplitude.
> 
> b) of course, for a fixed input frequency, the *output* frequency is
> proportional to the divide
> ratio. If you input 4Khz and divide by 8, you get out a 500Hz sawtooth
> with
> 8 steps. Assuming
> a -5V to +5V output scaling (like all the other signal generators), we
> have
> 10V/32 steps = 312mv/step. So for 8 steps = -5V to -2.5V sawtooth.
> 
> For straining the brain more: this acts as a low-pass filter! Since the
> divide ratio is a control
> voltage, then if the input is fixed (say 2Khz) then as the divisor is
> swept
> from 32 to 1 the
> amplitude AND frequency change. But, the amplitude drops off at higher
> frequency outputs
> since the counter is reset faster and faster.
> 
> Of course, if you fix the divide ratio and sweep the input, the amplitude
> of
> the sawtooth is *constant*
> at the divide ratio X 312mv.
> 
> Will add $15 to the cost of the module. Discuss!
>

> I studied the LM3900 app notes a year or two ago, and came to the same
> conclusion about the Serge pulse divider.  I'm as sure as someone who has
> never seen the insides of a Serge module can be that it's using a purely
> analog LM3900 staircase generator to do the dividing.  And part of me
> respects the pure-analog-ness of that solution. ;-)

There is a chance that Serge started with a 3900 circuit and upgraded it
to something more involved later, of course.

My own pulse divider story goes like this: Read the Serge catalogue,
thought it was a cool feature, designed a mildly involved analogue
circuit with CMOS gates and opamps (also a charge pump design),
and discovered that National application note *later*.

BTW, I wonder how Serge's phaser looks like, just for the sake of
curiousity.
I've once built the circuit from his patent (also LM3900-based, big
surprise),
and the effect was very interesting but not quite what I expected from a
phaser.
As the Serge phaser has a reputation for being very clean (and what I built
from the patent disclosure is the very contrary), I'm sure he's added a lot
of extra circuitry, or has switched to a different concept later.

JH.

I once opened up some later Serge modules with the intention of reverse
engineering them.  Saw lots of CA3280s but no 3900s, though this was in one
of the VCFs.  Didn't get far with the project, since the modules were very
tightly packed onto small pcbs and it wasn't my system to destroy.   

-----Original Message-----
From: jhaible@... [mailto:jhaible@...]
Sent: Monday, October 16, 2000 12:49 PM
To: motm@egroups.com
Subject: Re: [motm] Is this useful?



> I studied the LM3900 app notes a year or two ago, and came to the same
> conclusion about the Serge pulse divider.  I'm as sure as someone who has
> never seen the insides of a Serge module can be that it's using a purely
> analog LM3900 staircase generator to do the dividing.  And part of me
> respects the pure-analog-ness of that solution. ;-)

There is a chance that Serge started with a 3900 circuit and upgraded it
to something more involved later, of course.

My own pulse divider story goes like this: Read the Serge catalogue,
thought it was a cool feature, designed a mildly involved analogue
circuit with CMOS gates and opamps (also a charge pump design),
and discovered that National application note *later*.

BTW, I wonder how Serge's phaser looks like, just for the sake of
curiousity.
I've once built the circuit from his patent (also LM3900-based, big
surprise),
and the effect was very interesting but not quite what I expected from a
phaser.
As the Serge phaser has a reputation for being very clean (and what I built
from the patent disclosure is the very contrary), I'm sure he's added a lot
of extra circuitry, or has switched to a different concept later.

JH.

Hi All !

Subject says it all .

Down ?

Thanks .


Keep 'em oscillating :)


Hugo
=