[sdiy] Hypertriangularity and the 3340

[David Moylan]

Mark, I use the Texas Instruments CD74HC4046AM96, fixing pin 9 to a high 
voltage and controlling current on pin 11.  I'm also using it in a Delta 
Sigma application.  My target range is 140 kHz - 2.4 Mhz for the raw VCO 
(divided down by my Read/Write logic).  This range is bounded on the low 
end by my delta sigma loop breaking into oscillation and on the high end 
by the ADC I'm using (I was adding a loop to an existing ADC).  I had to 
trim both ends to keep them in bounds and could easily get way slower 
and up to about 4Mhz, but I wasn't trying to go faster so not sure what 
the upper bound is.

Sorry if this is a double post, had a mail hiccup on the first reply.

HTH

Dave

On 10/11/2017 07:45 PM, Mark Verbos wrote:
> Hi guys,
>
> The clock range is a huge thing. I have been experimenting a lot with Sigma-Delta type digital delays and using a 74HC4046 to get into faster ranges. I am not able to get down to 200kHz if I still want 5MHz. It kinda sucks honestly. If I could find an “ultimate” high frequency voltage controlled clock, I’d be very happy.
>
> Mark
>
>
>
>
> Sent from my iPhone
>
>> On Oct 9, 2017, at 07:59, Tom Wiltshire <tom at electricdruid.net> wrote:
>>
>>
>>> On 6 Oct 2017, at 17:40, KA4HJH <ka4hjh at gmail.com> wrote:
>>>
>>>
>>>> On Oct 6, 2017, at 11:23 AM, Tom Wiltshire <tom at electricdruid.net> wrote:
>>>>
>>>> Alternatively, in these modern days of plenty, you could use a 3340!!
>>> As Craig Anderton did with the HyperFlanger (or was one of Thomas Henry's?). IIRC, the main reason he did this was to be able to feed the sawtooth output back into the VCO to produce an exponential sawtooth wave. This eliminated the need for expo conversion on the input to the 4046 to sweep the comb filter response exponentially instead of linearly. I've never heard this effect but it *sounds* interesting.
>>>
>>> Um, I *think* he used a 4046 for the clock. I can't remember now but the trick would work with any linear HF-VCO circuit.
>>>
>>> My HyperFlanger manual is lost in a pile somewhere around here, along with most of my thoughts. 8/
>>>
>>>
>>> Terry Bowman, KA4HJH
>>> "The Mac Doctor”
>> I implemented an exponential clock modulation on the PIC-based flanger clock chip I did. It’s not a *hugely* noticeable effect, but it makes the LFO waveforms sound more like you expect them. Without it, they tend to linger at the top, sweeping through the endless Hertz of upper octaves before briefly sweeping the limited Hertz of lower octaves. That distorts the wave shape, at least according to human hearing. Of course, on a PIC, I could equally well have implemented an LFO with a hyper-triangle wave (I did exactly that once before) but in this instance, I wanted to allow the possibility of external modulation with the exponential response.
>>
>> http://electricdruid.net/flangelicious-a-super-dooper-flanger/
>>
>> One PIC is a lot simpler than a 3340, a 4046, and a 4041, although I could only get a 40:1 sweep, whereas Anderton’s more sophisticated solution manages 60:1, which is definitely at the top end of flangers.
>>
>> Tom
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-- 
David Moylan
Expedition Electronics
sonic adventures!