Exfo PSO-100 Series Optical Sampling Oscilloscopes Manual de usuario descargar pdf (Pagina 54)

Setting up and Using the Optical Sampling Oscilloscope

46 PSO-100

Using the Clock Input

To use the external clock input:

1. Connect an external electrical clock to the front panel.

The clock should have a peak-to-peak voltage between 0.8 and 2 volts

for clock frequencies up to 12.5 GHz. It will work also for lower

voltages, but with a slightly worse timing jitter. For clock frequencies up

to 25 GHz, higher voltages are required, between 1.5 and 3 V.

2. Select External from the Clock menu (constant time scale is

recommended for a high quality clock with low timing jitter). The

figure below shows an example using a 10 GHz sub-rate clock and a

40 Gb/s NRZ data signal, that is a ¼ clock sub-rate.

The clock signal itself is shown above the data signal.

Note: If the clock signal on the sample screen turns red, this indicates that the

clock signal is too low, and should be increased; or it may happen in a

measurement situation with frequency holes. It goes away after a while

(read more about frequency holes in Frequency Holes on page 120).

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Exfo PSO-100 Series Optical Sampling Oscilloscopes Manual de usuario Pagina 54