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Algorithm Reference
Frequency Offset
917 Frequency Offset
918 MutualFreqOffset
Single Side Band Modulation
PAUs:
2
Frequency Offset and MutualFreqOffset perform single side band (SSB) modulation. Essentially what
this means is that every frequency component of your input sound will be offset (in frequency) or
modulated by the same amount. In the Frequency Offset algorithm, if you have the OffsetFreq and
Offs Scale parameters set to a frequency of 100 Hz, then all frequencies in your sound will be offset up (or
down) by 100 Hz. Both algorithms produce modulation both up and down and you can control the
relative amount of up and down modulation with separate level and pan controls. The Frequency Offset
algorithms are very similar to Ring Modulator, which is a dual side band modulator. If you set the up and
down level parameters to match, the output will be quite close to the Ring Modulator output. Unlike Ring
Modulator however, you can choose to listen to just the up modulation or the down modulation, and not
necessarily both. In addition, you can pan the up and down modulation outputs in different directions
(left or right).
Figure 20
Single side band modulation (frequency offset) (i) down and (ii) up. When combined
(iii) we get dual side band modulation (ring modulation).
Frequency Offset is a mono algorithm that modulates your input signal with a pure sine wave. A sine
wave contains a single frequency, so your input signal will be offset in frequency by the frequency of the
sine wave.
Figure 21
Block diagram of Frequency Offset
A B
B- A
A+ B
Frequency
A B
B- A
A B
A+ B
L Input
R Input
Lowpass
SSB
Modulator
Sine
Generator
Pan
Pan
Wet
Dry
L Output
R Output
