In flat-top sampling, a hold circuit is sometimes required. This hold circuit can be designed as a sampler followed by

A capacitor can hold the voltage once it is changed, hence a shunt capacitor can be used as a hold circuit in flat-top sampling.

• In flat-top sampling, due to the lengthening of the sample, amplitude distortion and delay are introduced. This distortion is referred to as the aperture effect and occurs during the reconstruction of g(t) form s(t).
• The high-frequency roll-off filter with transfer function H(f) acts as a Low Pass filter that alternates the upper portion of the message spectrum, resulting in the distortion of the original signal.
• Aperture effect can be eliminated by using “Equalizer” in cascade with a reconstruction filter at the receiver to cancel the effect produced by the filter H(f) discussed.