Using the [ROTARY ENCODER] the range of frequency
displayed can be zoomed in or out.
Press [2] to pause/unpause the display (pause shown by
P on the screen). Press [1] to auto-scale the vertical dis-
play (shown by an R on the screen). Note that the rescal-
ing is limited and so for weak signals rescaling may not
cause the waveform to fully fit the display. Press
[BUTTON-
UP]
and
[BUTTON-DOWN]
to manually set the vertical display
scale (from x1 to x16 zoom).
[TIP] Use the spectrum analyzer feature
with ’page-lock’ enabled whilst adjusting parame-
ter controllers for e.g. filter cut-off or resonance
to see the effect on the waveform!
An automatic peak detector shows the frequency of the
strongest peak at the bottom right-hand side of the dis-
play. For example, in the figure there are many signal peaks
with the strongest one at 438 Hz.
[ADVANCED-INFO] Use the spectrum anal-
yser mode to look at the harmonics of a waveform.
With a sawtooth wave there are harmonics at 1f,
2f, 3f, 4f, 5f…all at decreasing strength. With a
pure square wave there are harmonics at 1f, 3f, 5f,
7f…that is the main reason for the different sound
to the ear. On the other hand, a pure sine wave
tone has only the 1f component. Look at the spec-
trum analyser signals and listen to the differences!
[TIP] Look at the spectrum analyser display
with high filter resonance, and sweep the cut-off
frequency around. You should see a moving strong
signal peak at the resonance frequency.
[TIP] Use the spectrum analyser to measure
the frequency of a continuous bass note. Change
the oscillator pitch and test out the response of
your sound system or room resonances!
[ADVANCED-INFO] Internally the spectrum
analyser feature works by digital sampling of the
audio signal over a fixed time period. Then an FFT
(Fast Fourier Transform) calculation is performed
on the samples to determine the strength of the
audio signal over a range of frequencies.
User Guide v1.31 [FOR SCREENREADERS]
page 44
Summary of Contents for Motas-6
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