What is an “octave”?
Figure 1: Two octaves at a manual
The meaning is taken from the music. An octave contains eight tones in the musical notation. The eighth tone has the double frequency of the first tone of an octave. The “concert pitch a ” has the frequency of exactly 440 Hz. The frequency spacing of a to a' is exactly an octave. The tone a' has therefore the frequency 880 Hz in the higher octave.
If a band width is dependent on the frequency and the exact cutoff frequencies are either variable or without meaning then the civing of frequencies in the measurement unit of octaves is often used in high frequency technology, too. An octave means here that the upper cutoff frequency is the double value of the lower cutoff frequency. Well, a certain assembly which contains a band width of one octave can used for example in the following frequency domains:
- 1 to 2 GHz, or
- 2 to 4 GHz, or
- 6,2 to 12,4 GHz, or
- 8,9 to 17,8 GHz.