Wavetek 147 Spécifications télécharger pdf (Page 95)

Field Sweeping with the SDA-5000: Considerations for Sweep in the Field

Signal Level Considerations

At amplifier test points, the same basic connection and signal level rules

apply to the SDA-5000 as apply to the headend unit. Too much signal level

on the input of the unit can cause inconsistent sweep readings. The forward

telemetry level should be 0dBmV±12dB at the input of the SDA-5000. This

can be verified by checking the lower right corner of the unit’s display while

sweeping forward (see “Forward Sweep Operation” on page 75). If the

telemetry level is too high, adding in-line attenuators or pads on the unit’s

input is a quick way to reduce signal level.

See Also

½ Chapter 14, “SDA-5500/SDA-5510 Sweep Considerations”

discusses the connection and signal level issues for

headend units.

If both the SDA-5500 and SDA-5510 units are in service, telemetry

frequencies for both the headend and field units must be entered during the

setup of the field units.

NOTE: The field units must also be set to the multiple user

mode (if you’re using the SDA-5510), even if only one of

the maximum ten people are sweeping.

Wiring and Levels: Forward Sweep

Only one cable is required for forward sweep testing. Simply connect a test

point from the output of the amplifier to be aligned or tested to the IN port of

the SDA field unit. If the video carriers in the signal are above +20 dBmV in

the signal after test point loss, then you should use an inline pad to drop the

level to no more than +10dBmV video carrier levels. (Typically this will be the

case only when direct connections to an amplifier output are used.)

NOTE: Remember, as stated previously, too much signal

level on the input can cause inconsistent sweep readings.

The forward telemetry level should be 0dBmV ± 12dB on

the input of the SDA field unit. This can be verified by

checking the lower right corner of the unit’s display while

sweeping forward. Inline pads provide a quick way to

reduce the signal level on the input.

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Wavetek 147 Spécifications Page 95