Extron electronic USP 405 manual Oscilloscope displays, Installation and Operation, cont’d

Installation and Operation, cont’d

8. View the horizontal phases again. If the phase difference is not zero, repeat steps 6 and 7 until the settings do not change.

9. Once the settings are stable, disconnect the oscilloscope, and reconnect the genlock cables.

10. Check the display(s) for proper colors and for undesirable artifacts in the image(s). Make adjustments as necessary.

11. If other USP 405s are part of this genlock daisy chain, connect the oscilloscope to each device, and repeat this procedure.

Oscilloscope displays

What you see on the oscilloscope while adjusting the USP 405 to match the genlock signal depends on the type of signal used, the type of oscilloscope, and the procedure the scope requires. This section shows some examples of oscilloscope displays.

The following diagram shows the genlock input signal (top) and an out-of- alignment NTSC composite sync output signal (bottom) displayed on a waveform monitor to check for alignment. When the phases are aligned, the wave peaks on the bottom waveform should line up with those in the reference signal above it.

Superimposed waveforms

With this method there is no way to know if the signals are 180º out of phase. A delayed sweep on a time-based scope would allow a more accurate display of the input and output signal phase relationships.

A vectorscope is more accurate than a waveform monitor. The following diagram shows an example of a vectorscope display when the horizontal phase is adjusted to align it with the burst (genlock) vector. Adjust the horizontal phase by rotating the horizontal Adjust () knob until the difference between the two vectors is 0º. This example shows black burst only (with no color). The burst vector is pointing to the left from the center.

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