Ultrasonic mixer

Greetings to All: There are RF mixers such as the SBL-1 which works well in the MHz range. I am interested in mixing 25KHz with 20KHz to get 5KHz and 45KHz such that I can hear the difference thru an amp & spkr. Does anyone have any ideas as to what to use for an ultrasonic mixer? Thank you 4 your time & attention.

Reply to
fred ander
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You can use a multiplier chip to mix things down to DC. Kinda spendy though.

I use the AD734.

George H.

Reply to
George Herold

The mixer can be air. MIT gave an award for the invention of the year around 2005 : Two ultrasonic loudspeakers send 20khz and 25khz airwaves to a point where they converge. People cannot hear either ultrasound, but the non-linear aspects of air cause a mixing of the two inaudible signals and people can sit at the point of convergence and hear the 5khz sound!!! No electronic mixer is needed, just ultrasound and air !!!!!!!!!

I independently invented this in 1987, but did not publish it. Imagine how a halloween ghost voice could be used to haunt a paranoid rival ! Ha ha.

Reply to
Globemaker

Analog multiplier?

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"For a successful technology, reality must take precedence 
over public relations, for nature cannot be fooled."
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Reply to
Fred Abse

Anything that multiplies.

  • An analog multiplier.
  • A handful of 4052 analog multipliers, some op-amps, and some logic
    formatting link
  • A handful of better quality analog switches and some logic.
  • An NE612.
  • A diode-ring mixer, either fed with some Great Big Transformers, or fed with balanced signals that are generated using op-amps.
  • Two ADC channels (if the signals are already in the analog world) and a DSP chip.

etc.

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Reply to
Tim Wescott

"fred ander"

** A simple JFET stage should do the trick.

Using say a 2N5457, just ground the source and feed to drain from a +5 volt supply with a 1k to 2.2k resistor.

The non linearity will be high.

.... Phil

Reply to
Phil Allison

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Not quite your conventional double-balanced mixer, but just for fun:

Version 4
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Reply to
John Fields

***************************************************** I'm sorry ! I have absolutely no clue what this list of #s means and/or what it is used for fredander
Reply to
fred ander

Just my Point! (in Electronics Design).

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John G.
Reply to
John G

"John G"

** FFS - LEARN TO TRIM !!!!

Dickhead !!

Reply to
Phil Allison

Phil Allison presented the following explanation :

Yes you are correct I should have deleted the rubbish that was of no use to the OP. He did not recognise it, much less be able to make any use of it.

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John G.
Reply to
John G

*************************************************************************** I'm sorry! I did not mean to cause any problems. I apologize! ! ! I will try not to ask any more questions of this forum. fredander
Reply to
fred ander

--
But, he acknowledged his ignorance and was supplied with the tools he
needed to be able to view the schematic and run the simulation.
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Reply to
John Fields

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You've done nothing wrong, so please don't be put off by the bad
behavior of some here.  
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Reply to
John Fields

It's an LTSpice listing.

LTSpice is available, free, from the Linear Technology website. Download and install it, copy the lines of the newsgroup article (from "Version 4" thru the last "TEXT" line) into any old text editor, and save it as, say, "jfields_mixer.asc", then start LTSpice, and open your saved .asc file there.

John's schematic should appear before your eyes, and you can run analyses on it, plot waveforms, and edit the schematic.

LTSpice is becoming the de facto standard for exchanging, comparing, and discussing circuit suggestions on sci.electronics newsgroups, principally because its source files are pure ASCII text.

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"For a successful technology, reality must take precedence 
over public relations, for nature cannot be fooled."
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Reply to
Fred Abse

to

l)

Dang, I forgot all about the diode ring.... And we sell a product that uses one!

(Are diode rings in the mini-circuits RF mixers?)

Thanks Tim

George H.

Reply to
patricia herold

**

Nah, ask more question! That's fine. You do need to have some thick skin at times.

George H.

Reply to
patricia herold

If your signals are pure sinewaves, a good mixer is a multiplier circuit (F1 and F2 inputs give an output that has (F1+F2) and |F1-F2| frequencies). If, on the other hand, your signals are squarewaves, like from a simple NE555 type oscillator, all it takes is an XOR gate, like (in CMOS through-hole package) CD4030 or CD4077. A dollar will buy you two, each has four XOR gates.

The range of analog mixers is large, and includes almost all nonlinear electronic parts: diodes, transistors, FETs. With some care in design, any of these can mix down ultrasound. The MiniCircuits mixers are based on matched diodes, Gilbert cells use matched transistors (usually in integrated circuit form). These cover more RF range than you need. One can wire the LM13700 into two multiplier circuits, and that's about a dollar.

See figure 6 in the datasheet...

Reply to
whit3rd

**

Fred. Just ignore the abusive posters. They are numerous and some are rather arrogant. However even some of them are correct occasionally.

Reply to
Ron M.

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