[sdiy] passive ring modulator transformers

[Tom Wiltshire]

The 4-quadrant modulator should be the same if you feed it square waves of equal levels.

Let's call the two logic states "-1" and "+1" instead of the typical "0" and "1". Now have a look at the truth table for XNOR:

 X | Y | Out
========
-1  -1  +1
-1  +1  -1
+1  -1  -1
+1 +1  +1

Looked at like that, it's pretty clear that XNOR does 4-quadrant multiplication, but just for a very limited case! (XOR is the same, but inverted). 

Tom


On 18 Jan 2016, at 19:10, Tim Ressel <timr at circuitabbey.com> wrote:

> Hi,
> I like them both. A clean ring mod aka 4-quadrant multiplier is nice and clean and I find most versatile. An XOR ring mod on the other hand is dirty and has more of those 'am radio' effects we all love. Being a modular synth guy I get to have both.
> 
> --TimR
> 
> On 1/18/2016 6:27 AM, Magnus Danielson wrote:
>> Hi,
>> 
>> There are many different "ring mod" sounds, and I've never really liked the MS20 XOR-gate solution myself (even if MS20 was my first synt). With a sufficiently clean sine and a ring mod (ring modulator - the diode ring in a double-balanced mixer) or Gilbert cell style multiplier is for me "cleanest" and most appealing, but that is my subjective view. 2-quadrant, 1-quadrant and even digital modulations has it uses too.
>> 
>> Cheers,
>> Magnus
>> 
>> On 01/18/2016 02:03 PM, Ullrich Peter wrote:
>>> Hi Tom!
>>> 
>>> Yes, the point "ring mod != 4 quadrant multiplier" is also mentioned on Neils Webpage...
>>> 
>>> I wonder that no one mentioned the Korg MS20 digital Ring modulator with XOR gate as we are already talking about active solutions...
>>> https://www.gearslutz.com/board/electronic-music-instruments-electronic-music-production/812474-ms-20-ring-mod.html 
>>> 
>>> Ciao
>>> Peter
>>> 
>>> -----Ursprüngliche Nachricht-----
>>> Von: Tom Wiltshire [mailto:tom at electricdruid.net]
>>> Gesendet: Montag, 18. Jänner 2016 13:34
>>> An: Ullrich Peter
>>> Betreff: Re: [sdiy] passive ring modulator transformers
>>> 
>>> A good part of that thread is Neil Johnson and Graham Hinton arguing about the "ring mod != 4 quadrant multiplier" point!
>>> 
>>> The rest of it has some interesting information though.
>>> 
>>> Thanks,
>>> Tom
>>> 
>>> On 17 Jan 2016, at 20:38, Ullrich Peter <Peter.Ullrich at kapsch.net> wrote:
>>> 
>>>> There is a nice discussion on Muffwiggler regarding Ring Modulators:
>>>> 
>>>> https://www.muffwiggler.com/forum/viewtopic.php?t=127474&postdays=0&postorder=asc&start=0 
>>>> 
>>>> Also the link to an Analog Devices Application Manual...
>>>> 
>>>> Ciao
>>>> Peter
>>>> 
>>>> http://www.ullrich.at.tt
>>>> 
>>>> 
>>>> 
>>>> 
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> 
> -- 
> --Tim Ressel
> Circuit Abbey
> timr at circuitabbey.com
> 
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