Precision low frequency generation

Couple of years ago in Wales.

Dirk

Er...

I'm a newbie-lurker to this group, and enjoy the subject matter because people are usually polite or flame with a joke, but I think Dirk have pressed the boundaries of etiquette. Oh, and BTW, I'd use a phase-shift oscillator. Ken

Just what the world needs, more CO2.

John

Phase-shift oscillators are textbook darlings that usually work badly in real life. Lots of drift, lots of distortion, hard to tune.

John

But there is an equivalent description of it as an amplitude modulated mid frequency. And more imporantly here if you synthesise the right hand side of the equation using a multiplier you can get what you want on the left hand side by filtering out the unwanted high frequency.

I note that you have deliverately snipped the context.

It does for the case where the modulation is by a lower frequency sine wave on the carrier.

A(t) = m(t)sin(wt)

Normal AM modulation would insist that m(t) > 0 and relatively slowly varying to keep the sidebands controlled.

And it suggests that a fairly cute way of getting what the OP wanted would be to tweak a classic FET square law AM modulator design to match his requirements. At these low frequencies it shouldn't be too hard. eg

Perhaps when you get out of secondary school you will learn how these things are related. Until then GROW UP!

Can someone please explain why Dirk Bruere has a net stalker called Phil?

Regards, Martin Brown

I think I dissed his posse once upon a time. Who knows? [Maybe not even Allison]

Dirk

"Dirk Bruere at NeoPax"

This vile psychopathic pile of **S*IT** must be exterminated from the face of the earth.

It may take any number of wooden stakes, driven through this vile zombie's heart.

Show no mercy - it ain't human.

...... Phil

Port timing could be precise *if* the verdammdt timer tick (aka RAM refresh) was not NMI.

Then use a microcontroller - MILLIWATTS (not 100+ watts).

A *linear* system *CANNOT* create anything not given to it; the output will be the arithmetic sum or differences of the inputs (only thing added is the noise of the circuit). Software digitizes, it IS NOT LINEAR.

Dirk Bruere at NeoPax snipped-for-privacy@gmail.com posted to sci.electronics.design:

After reading all this is still sounds like you want a ultra long record 2 to 20 Hz arb generator, based on a micro, with a web interface. Then the PC can do the heavy lift waveform synthesis, send the wave to the arb and out it goes. Memory is cheap, a couple gigs of flash and a hundred megs of ram buffers and a micro or an FPGA and you are in business. USB and Ethernet interfaces to boot.

Yeah use a subtractive amp.