Acterna SDA-5000 - CSO;CBT Measurements

Measuring System Performance: CSO/CBT Measurements
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CSO (Composite Second Order) is a clustering of second order beats at
certain frequencies in the spectrum. These beats cause interference to
picture quality when they fall within the video bandwidth. CTB (Composite
Triple Beat) is a clustering of third order distortion products usually around
the video carrier frequency.
The capability to make these measurements enables you to troubleshoot
and correct the cause of this unwanted distortion.
NOTE: Acterna recommends that a < 12 MHz band pass
filter be used to limit the amount of intermodulation
distortion caused by overload of the RF input of the SDA-
5000. If used, a preamplifier should be placed between the
band pass filter and the receiver.
In Spect mode, press the CSO/CTB soft key to initiate CSO/CTB
measurements. The SDA-5000 first switches to a 30 kHz resolution
bandwidth (see Fig. 6-11), measures the carrier, and then prompts you to
turn the carrier off. The signal must be unmodulated.
Fig. 6-11 CSO/CTB, Carrier ON
Press OK when the carrier has been turned off.
CSO/CBT MEASUREMENTS