# how do i suppress negative frequencies?

hi there. does any one know how i can suppress negative frequencies?
i need away for the frequencies to be detected and suppressed and raise up positive frequencies.

What do you mean by negative frequencies? (There are no negative frequencies in the real world because time doesn’t go backwards.)

You can use a high-pass filter, low-pass filter, notch filter, bandpass filter, or equalizer.

oh i see. then it must of been me and my energies thanks. thanks i’ve awakened the positive energie centers. thanks for the info

Are you trying to make the audio sound brighter, with more emphasis on higher frequencies?

Do you mean negative samples (the bottom half of the Audacity waveform is more prominent than the top half, or the bottom half goes further down than the top half goes up)?

Please give as much information as possible in your posts about what you are trying to do. Otherwise no-one will be able to understand you.

Gale

Only partially true.
Ever looked at a full Fourier transform? The values above Nyquist are the negative frequencies.
For a real input, the value pairs are just the conjugate of the positive frequencies, ie the imaginary (sine) part has its sign flipped.

They are important for (analog) filter design because the frequencies go around in a circle.
To make it a digital filter, you have to apply a bilinear transform which maps the 2*pi frequencies to the range 0 to Nyquist.

And it is for instance impossible to make a Hilbert transform/filter without manipulating exactly those frequencies.
What you’ll get after that is a analytic signal (the input is the real part and the output the imaginary one with 90 ° phase shift).
As most of these things, it’s just a conceptional/mathematical point of view.

Robert