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FM_ModTuned (FM Modulator, Tuned)

Symbol

Available in ADS

Parameters

Name

Description

Units

Default

Sensitivity

Modulation sensitivity, in Hz/Volt

kHz

1

Fnom

Nominal input frequency

GHz

1

Rout

Output resistance

Ohm

50

Notes/Equations
  1. This is a tuned modulator that selects the input harmonic defined by the specified Fnom frequency and frequency modulates it by the baseband modulation input.
    If there is no analysis harmonic frequency close enough to the Fnom frequency, a warning is issued and the output is 0. The two input impedances are infinite. The output impedance is set by Rout, and is limited to a minimum value of 0.1 Ohm. The open circuit output voltage is defined by

    where
    k represents the value at the analysis harmonic frequency closest to the Fnom value
    0 represents the baseband component of the modulation input voltage.
    For time t=0, the integrator of the modulation input signal is reset to 0. In all steady-state analyses such as harmonic balance, dc, and ac, time is kept at 0, so no modulation occurs.
  2. The RF carrier is injected at pin 1; the modulating signal is injected at pin 3. The resulting FM signal is present at pin 2. The RF carrier should be a frequency-domain source; the modulating signal should be a time-domain source.
  3. This model will not function as a frequency modulator in transient and baseband envelope simulations because of the use of the complex exponential operator.
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