Ultrasonic mixer

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

I use the AD734.

George H.

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.

Analog multiplier?

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.

"fred ander"

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

On Fri, 28 Oct 2011 01:15:09 -0700 (PDT), fred ander wrote:

---

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

Version 4 SHEET 1 1716 1092 WIRE 80 -256 -624 -256 WIRE 160 -256 80 -256 WIRE 528 -256 160 -256 WIRE 736 -256 528 -256 WIRE 1008 -256 736 -256 WIRE 80 -224 80 -256 WIRE 528 -208 528 -256 WIRE -624 -192 -624 -256 WIRE 1088 -192 944 -192 WIRE 1088 -176 1088 -192 WIRE 160 -144 160 -256 WIRE 80 -112 80 -144 WIRE 128 -112 80 -112 WIRE 272 -112 208 -112 WIRE 1008 -112 1008 -256 WIRE 944 -96 944 -192 WIRE 976 -96 944 -96 WIRE 128 -80 -256 -80 WIRE 1088 -80 1088 -96 WIRE 1088 -80 1040 -80 WIRE 1152 -80 1088 -80 WIRE 384 -64 336 -64 WIRE 528 -64 528 -128 WIRE 576 -64 528 -64 WIRE 672 -64 640 -64 WIRE 800 -64 672 -64 WIRE 832 -64 800 -64 WIRE 976 -64 912 -64 WIRE 272 -48 240 -48 WIRE 384 -32 384 -64 WIRE -480 -16 -512 -16 WIRE -448 -16 -480 -16 WIRE -352 -16 -368 -16 WIRE -272 -16 -288 -16 WIRE -256 -16 -256 -80 WIRE -256 -16 -272 -16 WIRE -240 -16 -256 -16 WIRE -160 -16 -176 -16 WIRE -48 -16 -80 -16 WIRE -16 -16 -48 -16 WIRE 144 -16 144 -48 WIRE 160 -16 160 -48 WIRE 160 -16 144 -16 WIRE 176 -16 176 -48 WIRE 176 -16 160 -16 WIRE 240 -16 240 -48 WIRE 944 -16 944 -96 WIRE 736 0 736 -256 WIRE 240 16 384 -32 WIRE 672 16 672 -64 WIRE 704 16 672 16 WIRE -624 32 -624 -112 WIRE -624 32 -672 32 WIRE 384 32 240 -16 WIRE 800 32 800 -64 WIRE 800 32 768 32 WIRE -272 48 -272 -16 WIRE 240 48 240 16 WIRE 272 48 240 48 WIRE 384 48 384 32 WIRE 416 48 384 48 WIRE 528 48 528 -64 WIRE 528 48 496 48 WIRE 560 48 528 48 WIRE 672 48 640 48 WIRE 704 48 672 48 WIRE -480 64 -480 -16 WIRE -48 64 -48 -16 WIRE 384 64 384 48 WIRE 384 64 336 64 WIRE -672 80 -672 32 WIRE 672 80 672 48 WIRE 384 96 384 64 WIRE 944 96 944 64 WIRE 272 112 240 112 WIRE -624 160 -624 32 WIRE 80 160 80 -112 WIRE 672 160 672 144 WIRE -480 208 -480 144 WIRE -272 208 -272 128 WIRE -272 208 -480 208 WIRE -48 208 -48 144 WIRE -48 208 -272 208 WIRE 240 208 240 112 WIRE 384 208 384 176 WIRE 384 208 240 208 WIRE 384 224 384 208 WIRE -480 256 -480 208 WIRE -624 304 -624 240 WIRE 80 304 80 240 WIRE 80 304 -624 304 WIRE 144 304 144 -16 WIRE 144 304 80 304 WIRE 384 304 384 288 WIRE 384 304 144 304 WIRE 736 304 736 64 WIRE 736 304 384 304 WIRE 1008 304 1008 -48 WIRE 1008 304 736 304 FLAG -480 256 0 FLAG -512 -16 f2 FLAG -16 -16 f1 FLAG -672 80 0 FLAG 672 160 0 FLAG 944 96 0 FLAG 1152 -80 f1-f2 SYMBOL voltage -480 48 R0 WINDOW 3 24 96 Invisible 2 WINDOW 39 0 0 Left 2 SYMATTR Value SINE(0 1 20k) SYMATTR InstName V1 SYMATTR Value2 AC 1 SYMBOL voltage -48 48 M0 WINDOW 3 24 96 Invisible 2 WINDOW 39 0 0 Left 2 SYMATTR Value SINE(0 1 25k) SYMATTR InstName V2 SYMATTR Value2 AC 1 SYMBOL res -352 -32 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R2 SYMATTR Value 10k SYMBOL res -64 -32 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R4 SYMATTR Value 10k SYMBOL diode -176 -32 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName D1 SYMATTR Value 1N4148 SYMBOL diode -352 0 R270 WINDOW 0 32 32 VTop 2 WINDOW 3 0 32 VBottom 2 SYMATTR InstName D2 SYMATTR Value 1N4148 SYMBOL res -288 32 R0 SYMATTR InstName R3 SYMATTR Value 10k SYMBOL res 64 -240 R0 WINDOW 0 -40 30 Left 2 WINDOW 3 -49 61 Left 2 SYMATTR InstName R5 SYMATTR Value 100k SYMBOL res 64 144 R0 WINDOW 0 -41 39 Left 2 WINDOW 3 -55 73 Left 2 SYMATTR InstName R6 SYMATTR Value 113k SYMBOL Comparators\\LT1711 160 -96 R0 WINDOW 0 35 -80 Left 2 WINDOW 3 11 -48 Left 2 SYMATTR InstName U1 SYMBOL res 368 80 R0 WINDOW 0 -38 45 Left 2 WINDOW 3 -48 73 Left 2 SYMATTR InstName R7 SYMATTR Value 20k SYMBOL cap 400 288 R180 WINDOW 0 24 56 Left 2 WINDOW 3 24 8 Left 2 SYMATTR InstName C2 SYMATTR Value 20n SYMBOL Digital\\or 304 -144 R0 WINDOW 0 -23 10 Left 2 SYMATTR InstName A3 SYMATTR SpiceLine trise 1e-7 tfall 1e-7 vhigh 3V vlow -3V SYMBOL Digital\\or 304 144 M180 WINDOW 0 -19 117 Left 2 SYMATTR InstName A4 SYMATTR SpiceLine trise 1e-7 tfall 1e-7 vhigh 3V vlow -3v SYMBOL res 512 32 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R1 SYMATTR Value 10k SYMBOL res 656 32 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R8 SYMATTR Value 10k SYMBOL cap 640 -80 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C3 SYMATTR Value 10n SYMBOL cap 688 144 R180 WINDOW 0 45 35 Left 2 WINDOW 3 20 5 Left 2 SYMATTR InstName C4 SYMATTR Value 5n SYMBOL res 928 -80 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R9 SYMATTR Value 10k SYMBOL res 512 -224 R0 SYMATTR InstName R10 SYMATTR Value 82k SYMBOL res 928 -32 R0 SYMATTR InstName R11 SYMATTR Value 10k SYMBOL res 1072 -192 R0 SYMATTR InstName R12 SYMATTR Value 10k SYMBOL Opamps\\LT1007 736 -32 R0 SYMATTR InstName U2 SYMBOL Opamps\\LT1007 1008 -144 R0 SYMATTR InstName U3 SYMBOL Misc\\battery -624 -208 R0 WINDOW 123 0 0 Left 2 WINDOW 39 0 0 Left 2 SYMATTR InstName V5 SYMATTR Value 3 SYMBOL Misc\\battery -624 144 R0 WINDOW 123 0 0 Left 2 WINDOW 39 0 0 Left 2 SYMATTR InstName V6 SYMATTR Value 3 TEXT -600 368 Left 2 !.tran 10ms TEXT -600 336 Left 2 !;ac oct 1024 1000 50000

-- JF

Just my Point! (in Electronics Design).

"John G"

D*****ad !!

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.

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

You, on the other hand - even though you're all mouth - didn't lift a finger to help the OP or make a comment about the circuit.

Instead, you seem intent on continuing a personal vendetta.

That's fine with me, but you've already proved that you're a malevolent little creep, so you'll have to work your way up from there.

-- JF

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.

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.

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

George H.

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...

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