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7
Chapter 7 Tutorial
Modulation
Phase Modulation (PM) PM is very similar to FM, but for PM, the
phase of the carrier waveform is varied, rather than the frequency. The
variation in phase of the modulated waveform from the carrier waveform
is called the phase deviation, which can vary from 0 to 360 degrees.
Frequency-Shift Keying (FSK) FSK is similar to FM except the
frequency alternates between two preset values. The rate at which the
output shifts between the two frequencies (called the "carrier frequency"
and the "hop frequency") is determined by the internal rate generator or
the signal level on the rear-panel Trig In connector. Frequency changes
are instantaneous and phase-continuous.
The internal modulating signal is a square waveform with 50% duty cycle.
You can set the internal FSK rate from 2 mHz to 100 kHz.
Frequency-Shift Keying
340
Modulating Signal
Modulated Carrier
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