White noise

[Kase]

How many signals are there in a white noise generator's output ( which is voltage vs frequency)? Can the whole frequency range be amplified? In a little detail, how can a frequency be kept unchanged, with only its voltage be a amplified?

 

[dave9]

?? It is one signal with variable frequency, so you can amplify it with a standard audio amplifier circuit you'd use for any other audio playback.

What are you trying to do? You can get a white noise audio file and play it on any normal audio player, home or portable stereo or phone or whatever.

 

[Harald Kapp]

a white noise generator's output ( which is voltage vs frequency)?

No. A noise generator generates voltage (or current, or power) vs. time (not frequency). The shape of the frequency spectrum of the signal defines what kind of noise it is.

In a little detail, how can a frequency be kept unchanged, with only its voltage be a amplified?

That is the inherent purpose of any amplifier: amplify the amplitude of the signal while keeping the waveform/spectrum of the output signal as true to the input signal as possible.

 

[Kase]

To dave9 and moderator:
Thank you for your replies. But I have already had a white noise source, so if I can try to learn some skill, I want to construct a (simple) amplifier myself. I shall ask more question(s), please, help me as much as you can. Thank you very much.

 

[bertus]

Hello,

When amplifying white noise, you must know over wich bandwidth you want to amplify.
Real white noise has a spectrum from 0 to infinity.
Practical white noise goes upto the bandwidth of the used amplifier.

Bertus

 

[Audioguru]

Audio noise can be white or pink. It has random frequencies and random amplitudes.
White noise has constant amplitude peaks vs frequency and sounds like mostly high frequencies.
Pink noise has equal power in each octave (white noise with a -3dB per octave lowpass filter) and sounds like it has all frequencies.
Pink noise is used to measure the frequency response of a loudspeaker.

 

[bertus]

Hello,

The wiki has a nice page about the colors of noise:
https://en.wikipedia.org/wiki/Colors_of_noise

Here is a simple circuit that creates white noise:
https://www.eeweb.com/simple-white-noise-generator/
When modified the frequency spectrum reaches into the RF range:
https://kb8ojh.net/projects/noisegen/

Bertus