Sum and Difference Frequency Generator

[danadakk]

A requirement came up for a design that needed to take an Fx and Fy input signal, and
generate the sum and difference freqs, then output as sine waves.

This is a general single chip approach. Basically the input signal periods are measured, the
sum and diff calculated, and then fed to an output DDS's to generate the Wavedac's clock.
Uses PSOC 5LP chip. The Wavedac is nothing more than DMA hardware feeding a table
of waveform data to internal DAC. So a wide variety of output sum and difference waveforms
can be implemented.

The approach has the latency of the math calculation and the freq cntr gate period.

Still substantial chip resources left for other uses, see right hand window, used/left resources.


Regards, Dana.

 

[KlausST]

Hi,

What you describe, isn't this what a simple mixer does?
Why do you do it digitally?
What's the benefit?

Klaus

 

[danadakk]

1) Tunability, bandwidth of solution, and accuracy of a DDS based solution. Eg signals
that are in freq domain that have small differential freqs.
2) Elimination of low accuracy / drift high order analog filtering components. Note chip has DSP if
that needed to be applied to incoming Fx and Fy. High order filters easy to implement.
3) Transform, map, an incoming f(t) signal to another y(t). This is of course another form
of filtering, applied to the output stage process.

I am limited in what further I can say about this, what I posted was a general capability.

Regards, Dana.