Teledyne LeCroy QPHY-BroadR-Reach - Manual (Page 27)

QPHY-BroadR-Reach Software Option
The disturbing sine wave shall be applied with the following characteristics.
Figure 20 – Disturbing Sine Wave Characteristics
Test Methodology:
The oscilloscope is set to acquire a 500 kS at 10 GS/s. The acquired signal has one and a half bits of
enhanced resolution (ERES) applied to it in order to limit the bandwidth of the oscilloscope to a value
which is suitable for this measurement. Ten records are taken, saved to file, and then passed through the
MATLAB script from the specification. The MATLAB script removes the disturbing sine wave and
measures peak distortion at equally spaced phases of the symbol period. To pass, the MATLAB script
must measure less than 15mV distortion for all 10 records.
In order to properly line up the samples it is important that the exact symbol rate is used. If Test Mode 2
was run during this session the measured symbol rate can be used, otherwise it can be entered as a
variable. It is important that the oscilloscope, DUT, and disturbing sine wave source are all frequency
locked to the transmitter reference clock.
Figure 21 – Transmitter Distortion Test Setup
922533 Rev B 27