Response Optimization Modes - Teledyne LabMaster 10 Zi Series Operator's Manual

Response Optimization Modes

Frequency response and group delay of the oscilloscope contributes to
the pulse response characteristics of the oscilloscope. By slightly
adjusting these characteristics using digital signal processing, the
characteristic response of the oscilloscope can be optimized for your
specific application.
Frequency response is defined as the decrease in the magnitude
response with respect to frequency. A fourth-order Bessel roll-off
slightly attenuates the frequencies near the bandwidth rating of the
oscilloscope while a brick-wall frequency response passes slightly higher
frequency content.
Group delay is defined as the rate of change of the total phase shift with
respect to angular frequency through a device or transmission medium.
Amplifiers in analog oscilloscopes typically have some group delay at the
highest frequencies. This inherent group delay minimizes the preshoot
present on a step response and provides the traditional pulse response
with no preshoot before the step. When zero group delay is provided at
all frequencies, preshoot and overshoot is equalized.
Teledyne LeCroy provides three choices for Response Optimization
Mode selection. These choices combine a frequency and group delay
response to optimize the oscilloscope for particular applications.

Pulse Response - A group delay compensation minimizing
preshoot, this selection most resembles the response of an
analog oscilloscope by controlling group delay to be slightly non-
zero at the highest frequencies. In addition, a fourth-order Bessel
frequency response is implemented.
LM10Zi-GSM-E Rev A
Getting Started Guide
89