Method and system for correcting frequency response of a signal sampler

A method of filtering a signal under test (SUT) sampled by a sampler, the method comprising:

• applying a first transfer function to a first frequency range of the sampled SUT, the first transfer function comprising dividing a reference frequency response of the sampler by an actual frequency response of the sampler to provide a correction of the actual frequency response of the sampler;
• applying a second transfer function to a second frequency range of the sampled SUT, the second transfer function comprising gradually removing the correction of the actual frequency response of the sampler over the second frequency range;
• and
• applying a third transfer function to a third frequency range of the sampled SUT, the third transfer function comprising compensating for excess gain incurred while applying at least one of first and second transfer functions to the first and second frequency ranges, respectively, in order to preserve statistics of the asynchronous components of the sampled SUT.

A filter for filtering a signal sampled by a sampler in an equivalent time oscilloscope, to preserve asynchronous components of the sampled signal, the filter comprising:

• a first filter region configured to apply a correction to an actual frequency response of the sampler with respect to a reference frequency response;
• a second filter region configured to gradually remove the correction of the actual frequency response of the sampler over a second frequency range, the second frequency range being higher than the first frequency range;
• and
• a third filter region configured to compensate for excess gain incurred by the first and second filter regions in order to preserve statistics of the asynchronous components of the sampled signal, the third frequency range being higher than the second frequency range.