HP Cable Box 8591C manual Frequency Reference Level

Getting Started

Making a Measurement

When the peak of a signal does not appear on the screen, it may be necessary to adjust the amplitude level on the screen. Press @GKiKKZJ

REF LEVEL 48.8 dBmV appears in the active function block. The REF LVL softkey label appears in inverse video to indicate that reference level is the active function. The reference level is the top graticule line on the display and is set to 48.8 dBmV. Changing the value of the reference level changes the amplitude level of the top graticule line.

If desired, use the reference level function to place the signal peak on the screen using the knob, step keys, or number/units keypad. (Marker functions determine the frequency and amplitude of a signal.)

Figure 2-5 demonstrates the relationship between center frequency and reference level. The box in the figure represents the cable TV analyzer screen. Changing the center frequency changes the horizontal placement of the signal on the screen. Changing the reference level changes the vertical placement of the signal on the screen. Increasing the span increases the frequency range that appears horizontally on the screen.

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FREQUENCY

REFERENCE

LEVEL

FREOUENC Y

Figure 2-5. Relationship between Frequency and Amplitude

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