subtr. heterodyne math

Consulting services are available to program this into Excel, MathCad, Matlab, or 8048 assembly. Operators are standing by.

f1 / f2 = 0.6 f1 = 0.6 * f2

f1 = f2 - 8 f2 - 8 = 0.6 * f2

f2 - 0.6*f2 = 8

f2 = 20 f1 = 12

I read in sci.electronics.design that Claus Jensen wrote (in ) about 'subtr. heterodyne math', on Tue, 8 Feb 2005:

F1 - F2 = 8................. (1)

F2 = 0.6 x F1............... (2)

Substitute from (2) in (1):

F1 -(0.6 x F1) = 8

F1 = 20 Hz

and thus F2 = 12 Hz

Maybe I didn't understand the question.

I read in sci.electronics.design that PN2222A wrote (in ) about 'subtr. heterodyne math', on Mon, 7 Feb 2005:

No credit because no working is shown. If there had been, you would have found that F1 is the higher frequency.

No, the ratio of F1 to F1 is stated to be 1: 0.6, so F1 is larger than F2.

Hello Claus,

I guess the math is easy and has been explained. As to the XR chip I am not sure how to generate that without lots of alignment. I would cheat and used a couple DDS chips. Computer does the math, send it to the chips and out come the two desired sine waves.

Regards, Joerg

As an NZ'er you should know Harmer's Law, postulated by Brian Harmer, of WYSIWYG fame.

All spelling/grammar corrections on Usenet have an eery tendency to have spelling/grammatical errors.

Can someone help me get my head around this.

I need to generate a signal comprised of two sinewaves, F1 and F2, one each from something like an XR2206. IOW their outputs are to be summed.

The criteria is that the difference between the two generated frequencies must be a specific single frequency, and that the ratio of F1:F2 must be specifiied.

Here is an example of what is required.

The frequency difference between F1 and F2 to be 8Hz. The ratio between the F1 and F2 frequencies to be 1:0.6, ie, 1 to 0.6.

How do I solve this mathematically?

Claus

"Joerg" a écrit dans le message de news:vBSNd.1997$ snipped-for-privacy@newssvr24.news.prodigy.net...

Or you can use an XR to generate 16Hz, divide by 4 for 4Hz and mix :-)

Just one pot to trim!

^^^^

Let he who is without typos cast the first virtual stone :)

Cheers Terry

:)