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SampleHoldSML (Sample Hold)

Symbol

Available in ADS

Parameters

Name

Description

Units

Default

Fnom

Nominal input and output frequency

Hz

0

Notes/Equations
  1. This model samples the input signal and holds it until the next sample event. It is a tuned model; it selects and holds just the signal at the input harmonic closest to the frequency specified by Fnom. If there is no analysis harmonic frequency close enough to the Fnom frequency, a warning is issued and the output is 0. The input impedance of both the sample clock input and the signal input is infinite. The output is a voltage source with a fixed impedance of 0.1 Ohm.
  2. The sampling instant is defined to be when the sample clock input rises through the 0.5V fixed threshold. If the baseband mode of operation is specified (Fnom ~ 0 Hz), this behaves as a normal sample and hold; the baseband input voltage at the sampling instant is output and then held indefinitely at this constant value until the next sample. If an envelope carrier frequency is specified by Fnom, the signal component at this envelope harmonic frequency is selected and its complex value at the sampling instant is held at the output. This held output appears at the same envelope harmonic frequency. For example, if an envelope analysis with a fundamental of 1 GHz is performed with a timestep of 0.1nsec and an offset frequency source at 1.001 GHz is sampled, the complex value of the envelope is sampled and held constant. The output will appear to be at the 1 GHz fundamental frequency since the complex envelope is no longer changing, until the next sample event.
  3. The Sampler model samples the entire spectrum and outputs just a real baseband voltage.
  4. SampleHoldSML works in transient and circuit envelope simulation. In transient simulation, Fnom has no effect because all signals are baseband only.
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