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# LimiterSML (Limiter)

## LimiterSML (Limiter)

##### Symbol ##### Parameters

Name

Description

Units

Default

Gain

Linear gain (real only)

None

1.0

Vmax

Maximum output voltage

V

5

Vmin

Minimum output voltage

V

−5

Rout

Output resistance

Ohm

50

Fnom

Nominal input frequency

Hz

0

Fnom ≥ 0

##### Notes/Equations
1. The Gain parameter is a real value only (not in dB or complex).
2. This model can be used in transient, harmonic balance and circuit envelope simulations.
3. When used in transient simulations, Fnom must be set to zero. Gain, Vmin and Vmax determine the output voltage time series. The output voltage time series is calculated as Gain times the input voltage time series, but is hard limited to Vmin and Vmax in case the value drops below Vmin or rises above Vmax. Hard limiting is not allowed to reduce the magnitude of the output waveform amplitude by more than a factor of 10-4 at any point in time. For example, a sine wave with a 106 V amplitude as input to a LimiterSML component with Gain=10, Vmax=1, Vmin=-1, will scale to an output waveform amplitude of 103 V, not 1 V. The value 103 comes from 106 x Gain x 10-4, where Gain=10 in this example.
4. When used in harmonic balance simulations, Fnom must be set to a non-zero fundamental or intermodulation frequency. Fnom, Gain and abs(Vmax) determines the output voltage spectrum (Vmin is not used). The output voltage spectrum is calculated as Gain times the input voltage spectrum but is scaled by min(abs(Vmax)/abs(V(Fnom)),1) at all frequencies, where
V(Fnom)=Gain x Vin(Fnom). This gain limits the entire frequency spectrum by abs(Vmax)/abs(V(Fnom)) in the case where abs(V(Fnom)) exceeds abs(Vmax). If there is no spectral component at Fnom, no gain limiting is performed. No minimum gain of 10-4 applies in this case.
5. When used in circuit envelope simulations, Fnom can be a zero or non-zero fundamental or intermodulation frequency.
• If Fnom is zero, the mode of operation is similar to that for transient analysis. If there is a baseband signal, it is hard limited as dictated by Vmin and Vmax. Hard limiting is not allowed to drop the magnitude of the output voltage by more than a factor of 10-4 at any time (refer to note 3). All other spectral components are scaled accordingly. If there is not a baseband signal, nothing happens.
• If Fnom is a non-zero fundamental or intermodulation frequency, the mode of operation is similar to that for harmonic balance analysis. All spectral components, including the baseband signal if applicable, are gain limited as dictated by min(abs(Vmax)/abs(V(Fnom)),1). For harmonic balance analysis, the value of Vmin does not matter in this case.
6. LimiterSML has more than one mode of operation. It performs clipping or limiting in a Transient or Circuit Envelope analysis, and it performs gain scaling on the spectral components in a Harmonic Balance analysis. Its mode of operation depends on the value of Fnom and the type of simulation being performed.
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