[Laser] Ultrasonic Modulator?

[J. Forster]

There are two easy ways to do it, an analog multiplier or a diode ring mixer.
I'd use the analog multiplier because the frequency is so low. Think Analog
Devices or National.

You will need to amplify the mike signal to a few volts p-p, then add a DC
signal ( this can be simply done with 1 op-amp) into it so that the signal never
goes below ground, then put it into one port of the multiplier. The carrier
oscillator goes into the other port. The output goes to the power amp.

-John


KD7JYK, 49H7KR wrote:

> I am looking for a circuit where I can mix a VFO from around 10 - 30 KHz
> with a microphone.  Nothing fancy, AM OK.  This group is as close as I can
> think of for this project, I want to super-impose my voice on an ultrasonic
> carrier and send it a distance using some high power tweeters I have.  I
> have tracked down numerous sources of amplifiers that will cover this audio
> range up to several tens of Watts, looking for a modulator.
>
> Any ideas?
>
> Kurt
>
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