FM_DemodTuned (FM Demodulator, Tuned)
Symbol
Available in ADS
Parameters
Name |
Description |
Units |
Default |
---|---|---|---|
Sensitivity |
Demodulation sensitivity, in Hz/Volt |
kHz |
1 |
Fnom |
Nominal input frequency |
GHz |
1 |
Rout |
Output resistance |
Ohm |
50 |
Notes/Equations
- This is a tuned demodulator that selects the input harmonic closest to the specified Fnom frequency and generates a baseband output signal equal to the instantaneous frequency of the selected carrier frequency.
If there is no analysis harmonic frequency close enough to the Fnom frequency, a warning is issued and the output is 0. Input impedance is infinite; output impedance is set by Rout, and is limited to a minimum value of 0.1 Ohm.
The instantaneous frequency difference is equal to the time derivative of the instantaneous phase. This is approximated using a simple finite difference. As long as the phase does not change by greater than 180° in one time step, the frequency calculation is non-ambiguous. The open circuit output voltage can be described as:
where
k represents the value at the analysis harmonic frequency closest to the Fnom value
0 represents the baseband component of the output voltage.
All non-baseband output frequency components are 0. - For transient and baseband envelope simulations, this model does not generate the expected results because the imaginary part of baseband signals is 0.