Teledyne LeCroy Eye Doctor II - Manual (Page 18)

Eye Doctor II Software
De-embed Channel / De-embed Fixture
The De-embed Channel / De-embed Fixture configuration allows to you both de-embed a fixture and de-
embed a serial data channel at the same time. This is used when using a fixture to measure at the
receiver side of the serial data channel. It moves the measurement reference back to the output of the
transmitter. You then see what the serial data signal looked like at the transmitters output with the
effects of the channel and fixture removed.
De-embed Fixture Only
The De-embed Fixture Only configuration allows you to remove the fixture effects from you meas-
urements. You can then see what the serial data signal looked like at the transmitters output with the
effects of the fixture removed.
Bandwidth Limit
When De-embedding fixture or channels a bandwidth limit is required and must be set.
Bandwidth Limit imposes a reasonably sharp low pass filter in addition to the S-Parameter system
response. This is useful when de-embedding a lossy channel, to limit the amount of boost applied. When
a channel is de-embedded, high frequency response must be boosted to compensate for the high
frequency attenuation in the channel. However, if the signal has been attenuated into the noise floor,
boosting the signal on the oscilloscope makes it impossible to distinguish between the signal and the
noise. The system boosts the noise along with the signal. The Bandwidth Limit setting can limit the
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