Generating A Noise Signal from a Digital Processor

[amanno]

Hey guys,

If I wanted to go about generating just a plain noise signal (don't care what the signal consist of), at a certain frequency (say 10 MHz) what is the best way to go about doing that?

If possible I would really like to use a microprocessor or ARM processor (due to the higher frequency) to generate this noise signal, however this will only produce a digital signal as a pin is switched from low to high.

Is there a simple way to transform the signal into a sine wave, without using something like a DAC since I don't care about the signal and just want noise? Or maybe a better way to generate a noise signal than using a processor?

Is there an IC power inverter for this purpose?

 

[berkeman]

Hey guys,

If I wanted to go about generating just a plain noise signal (don't care what the signal consist of), at a certain frequency (say 10 MHz) what is the best way to go about doing that?

If possible I would really like to use a microprocessor or ARM processor (due to the higher frequency) to generate this noise signal, however this will only produce a digital signal as a pin is switched from low to high.

Is there a simple way to transform the signal into a sine wave, without using something like a DAC since I don't care about the signal and just want noise? Or maybe a better way to generate a noise signal than using a processor?

Is there an IC power inverter for this purpose?

Welcome to the PF.

The simplest way is to use a random number generator to drive a DAC. You can do all of that in the uC.

If you program in C, there may already be a random() function available, depending on the version of C. If not, it is straightforward to make your own random number generator code (check wikipedia).

Making a DAC is simple with a uC as well. Look up R-2R ladder DACs -- you just use however many IO lines you want (8 to 12 usually) to form the DAC with resistors and a follower buffer.

 

[sophiecentaur]

The important thing with a 'numerically generated' noise signal is that it is not truly random. It will repeat itself, eventually. As long as the repeat is at a slow enough rate for the system you are using it into ignore it then you are ok. It isn't that difficult to achieve this but it's just something that you may want to bear in mind.