rind mod idea

[Scott Bernardi]

Where's my brain? Of course you can't do a balanced modulator with just
summers and differencers! A balanced modulator will give you the sum and
difference FREQUENCIES, suppressing the original frequencies. No matter how
you mix two different frequency signals by adding them or subtracting them,
you are still going to get some sort of mix of the original frequencies.
Let's say you are mixing two sine waves of 800hz and 1000 hz. In straight
sum and diferrence amps, you are going to get a signal with some mix of
800hz and 1000hz.
In a balanced modulator, you will get the sum frequencies -
(800+1000)=1800hz, and the difference frequencies, (1000-800)=200hz. The
original 800 and 1000hz signals are suppressed.


>I don't believe what you describe here can give you a true ring modulator,
or "balanced modulator". Every circuit I've ever seen involves the use of a
four quadrant multiplier, not just sum and difference amplifiers.
>
>


At 04:03 PM 6/22/98 -0400, you wrote:
>Hello,
>
>I'm still recovering from that though u.s. loss yesterday.
>
>I'm new to electroinics, but I'm trying to design a ring modulator
>and have a couple questions.
>
>I have a book based on the 747 op-amp. In the book
>are small circuits for a summing amplifier and a differential amplifier.
>I was thinking that I could combine these two circuits and mix the
>outputs add a couple audio jacks and presto a genuine ring modulator,
>none of that one-input ring-mod with an internal oscillator.
>
>Now this seems almost too easy, so please tell me where I going 
>wrong...
>
>secondly, I was looking at a modulator system and saw what looked like
>a mini-patchbay that was called multiples or multiplier...
>
>could somebody explain what that is(I have a hunch) and 
>if it's simple, how to put one together.
>
>thanks in advance,
>Kristjan
>
>
>
--------------------------------------
Scott Bernardi
voice: 415-538-0439 (note new number)
fax:   415-904-8375
scott.bernardi at fritz.com