Ultrasonic mixer

[whit3rd]

On Friday, October 28, 2011 1:15:09 AM UTC-7, fred ander wrote:

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.

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...
<http://www.national.com/mpf/LM/LM13700.html#Overview>

 

[Ron M.]

On Oct 30, 3:29 am, fred ander <fredander...@gmail.com> wrote:

On Oct 29, 9:09 pm, John G <greent...@ozemail.com.au> wrote:

Phil Allison presented the following explanation :> "John G"

LEARN  TO  TRIM  

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.

--
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

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