Wasps, DCOs, OSCs and Bill Clintons pants?

[Bjarne Nillson]

>>What is a true DCO ? - a good philosophical point.

Concerning the discussion Wasp,Oscar and DCO or VCO.

First of all, there are nothing wrong in using the divide 
N value counter as a oscillator(ex 8253).
In fact it do behave allmost like a odinary VCO regarding to
the upper frequency range where it starts to track badly,
just like a odinary VCO does. :-)

Nevertheless, compared to a odinary VCO it have supperior 
linearity, super stable over the temp range,true HARD sync.
At least a wery clear sync sound compared to some 
other sync solutions.

Now, how do we change the square wave to a saw!
Easily by a odinary integrator,the same integrator used in a VCO!

Now, the discussion starts to be interesting,
What is a VCO and what is a DCO???

Lets compare a P5 and a JX3P, the P5 have a CPU driving a DAC
who outputs a voltage to set the pitch of the oscillator.

Now, we can for sure call this a DCO??
Nooo?? Yes offcourse,a Digitaly Controlled Oscillator, right!

In the JX3P we have a CPU driving a DAC who outputs a voltage
to the integrator as a bias voltage as a compensation for the
loss of amplitude in the integrator as more the frequency 
in the VCO increases. 
Did I say VCO?? Yes,VCO!

Well, we do have a voltage controlling the oscilator here! Right!

I hope you have started to se my point here! 

One other point is, what does the word VCO or DCO stand for!

Is it the technology used! 

Or is it a marketing thing only!

Or does it only have with the application to do!

Or is it because the divide by n value counter is the actually
oscillator outputing only a square wave, and the frequency
directly controlled by the CPU inserting a 16 bit word in to 
the counters frequency controll register.

The same apply to VCF contra DCF, VCA contra DCA.
I mean, no one are argumenting about a LFO,Low Frequency Oscillator.

So why not calling a VCO or DCO for WFG instead, Wave Form Generator!!
Perhapps with a D or a A in front,of WFG depending of the way to 
generate the wave!

Regarding to the many synths using the divide by N value oscillator
BIT99/01,JX3P,Juno60/6,JX70,JX8P.MKS30,OSCar,Wasp,Gnat,
DW6000/8000,Juno1/2.Novation Bassstation ,Matrix6,MS6 etc,
most of them sound wery good.

And the way the divide oscillator are used are quiet interesting,
take the Bit99 for example it using two counters for each voice
but has a VCO (74LS221) as the master oscillator for the frequency
applyed to each counter.The pitch bend and LFO voltages are applied to
this VCO!! Strange, what do we call this?? a VCODCO or what???

Or the Oscar,this synth are using the divide 
counters in conjunction with
a 4046pll for reading waves from a ram memory.
The idea is brilliant but have a dravback and that is the PLL filter
who are slowing down the response time of the oscillator concidderably.

You can test this out by playing a low note and then a high note,
you can then hear a short glitch/portamento.

But i may be totally wrong in this conclusion!
I have not done any calculations on this PLL so it may be 
some instructions latency time in the Z80 who makes this
glitch..!!

This was just some small philosphying about 
this issue, nothing to fuzz about.



BJ [in the lands of confusion and only 9 000 000 citisens!]


PS:Please respond to the list adress not mine privately.






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