Generating a tone that will cause aliasing is not mapped into the right frequency


I will appreciate your help with understanding the following:

  • In audacity I am choosing my project sample rate to be 8KHz (Edit–> Preferences), which means no aliasing for sound tones with frequencies of 0-4kHz.
  • By using Nyquist prompt with the following command: “return hzosc(7000)”, I am trying to generate a tone with frequency of 7KHz
  • Due to the aliasing, I am expecting to get tone with 1kHz but instead I am getting ~3KHz.
    (I see it by using the plot Spectrum feature).

I wondered why this is the result (3kHz instead of 1kHz tone after generating 7Khz tone with sampling rate of 8kHz)

I am using version 3.5.1

folding ? … Aliasing - Wikipedia

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Can you explain?

According to my knowledge I will still expect to get 1khz signal.