I know that I saw a circuit somewhere, which produced both side bands separately. Has anyone come across such a circuit before?
What I was wanting to do is input the fundamental frequency at x and y to produce x+y then keep going until I produce 9 harmonics with a view to then add harmonics together in a mixer in order to create timbres. Additive synthesis is what I am going for.

 

I know that I saw a circuit somewhere, which produced both side bands separately. Has anyone come across such a circuit before?
What I was wanting to do is input the fundamental frequency at x and y to produce x+y then keep going until I produce 9 harmonics with a view to then add harmonics together in a mixer in order to create timbres. Additive synthesis is what I am going for.

X * Y will give you sidebands.
X + Y can be created with simple summing opamp.

 

I would synthesize different waveforms digitally using a microcontroller.

 

Okay, so to achieve multiples of the same frequency, are you suggesting that a summing arrangement would work? I may have to try that again and view with an oscilloscope instead of just relying on my ears.
Why is it said that side bands are a-b and a+b?

 

Okay, so to achieve multiples of the same frequency, are you suggesting that a summing arrangement would work? I may have to try that again and view with an oscilloscope instead of just relying on my ears.
Why is it said that side bands are a-b and a+b?

In a superheterodyne radio receiver, a local oscillator is mixed with the incoming RF signal to produced the IF (intermediate frequency).



The mixer circuit is a multiplier because the math produces sum and difference fequencies known as sidebands.

cos(A) x cos(B) = ½ [ sin(A+B) + sin(A-B) ]

(A-B) is called the lower sideband.
(A+B) is called the upper sideband.

The same thing happens when you modulate (multiply) a carrier frequency fc with a modulating frequency fm.

 

Okay, so to achieve multiples of the same frequency, are you suggesting that a summing arrangement would work? I may have to try that again and view with an oscilloscope instead of just relying on my ears.
Why is it said that side bands are a-b and a+b?

In order to create multiples of a frequency I would generate the signals digitally in an MCU and simply add them.

PASCO 9307 is a Fourier Synthesizer for experimenting with various combinations of frequency harmonics.

 

Gotta love math. Multiply to get + and -. Not confusing at all. Ha ha. I will experiment with modulation and summing circuits again.
Analogue is what I am into. Although, I have an idea of using the data out of an eeprom to generate waves. Looks doable on paper.

 

Gotta love math. Multiply to get + and -. Not confusing at all. Ha ha. I will experiment with modulation and summing circuits again.
Analogue is what I am into. Although, I have an idea of using the data out of an eeprom to generate waves. Looks doable on paper.

Are you and TS (the thread starter) Aus_DIYer the same person?

 

Tis me. I used my phone.

 

Tis me. I used my phone.

Ok. It gets confusing when a member is registered under different accounts.
It doesn't matter what device you use. You can still log in under the same account.
State which account you wish to keep and admin will merge all posts into the one account.

 

I think I fixed some of the account problem on my side. I must have created an account using my google password, which I forgot.

 

I do appreciate the idea of buying a ready made machine which will do exactly what I want. However, I do not have thousands of dollars spare at present. I do have heaps of ICs and other components and lots of spare time.