Moog Music Voyager Old School - Manual (Page 26)

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Voyager OS User’s Manual - The Components
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Voyager OS User’s Manual - The Components
G – The LFO
The Voyager OS has a dedicated Low Frequency Oscillator (LFO). The LFO produces triangle and square
waves as well as stepped and smoothed Sample & Hold (S&H) signals over a range of approximately 0.2 to
50 Hz. The LFO signal is available as a modulation source on both Mod Busses.
For the Sample and Hold circuit, the LFO’s square wave is used as the S&H Trigger
input, while the Voyager’s Noise source is used for the S&H Input signal. For each
positive-going cycle of the LFO square wave, the voltage at the input of the S&H
circuit is sampled and held until the next cycle. Since the sample source is Noise
(a random signal), the voltage that appears at the output of the S&H circuit is a
random voltage that changes in time with the LFO.
The Voyager’s CV Interface jacks on the back panel of the Voyager allow additional
fl exibility with the Sample and Hold circuit. For example, if a plug is inserted into
the S&H Gate input, it will disconnect the LFO trigger; an external gate signal can
then be used to trigger the S&H circuit. Similarly, a plug inserted into the S&H
Input jack disconnects the Noise source from the S&H input. In this circumstance
when the S&H circuit is triggered, the voltage at the tip of the plug is held at the
output of the S&H circuit. This makes it possible to get interesting modulation
patterns such as the ‘staircase’ modulation shown below.
The Voyager’s Sample and Hold circuit can
create more than just random signals –
interesting stepped modulation patterns
are also possible.