HP Cable Box 8591C manual Gate Not Occurring During the Pulse

Making Measurements Using Spectrum Analyzer Mode

Using the Time-Gated Spectrum Analyzer Capability Without the Gate Utility (Option 107 only)

Setting the Gate Delay and Gate Length Properly, When NOT Using the Gate Utility

If the gate delay and gate length are not set properly, you may not be viewing an accurate representation of a signal. For example, If the gate does not occur during the RF pulsed signal, the amplitude of the signal displayed on the spectrum analyzer is lower than the actual signal. See Figure 5-26.

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tRES BW 1E0 kHz #UBW 108 kHz aswp 150 msec R'

Figure 5-26. Gate Not Occurring During the Pulse

The time gate is implemented after the resolution bandwidth filtering and before the video filtering. The displayed signal is a result of the decay time for the resolution bandwidth hlters and is not an accurate representation of the input signal.

If the gate occurs at the beginning of the RF pulse signal or at the end of the RF pulse signal, the signal displayed on the spectrum analyzer can be attenuated or contain transient signals caused by the spectrum analyzer (see Figure 5-27). If this happens, decrease the gate length and change the gate delay to place the gate output during the signal.

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