HP Cable Box 8591C N dB Bandwidth Measurement

N dB Bandwidth Measurement

It is often necessary to measure a signal response’s bandwidth, such as when testing a band-pass lilter. The signal to be measured must be centered on the display with a span that includes the full response. Activate the measurement by turning the N dE! PTS ON OFF key (ON). The spectrum analyzer places arrow markers at the -3 dB points on either side of the response and reads the bandwidth. For other bandwidth responses enter the number of dB down desired, from 1 dB to 80 dB.

No other signal can appear on the display within N dB of the highest signal. The measured signal cannot have more than one peak that is greater than or equal to N dB. A signal must have a peak greater than the peak excursion to be identified. The default value for the peak excursion is 6 dB.

The N dB bandwidth measurement error is typically:

•about f2 % of the span, for spans < 10 MHz

•about f3 % of the span, for spans > 10 MHz

2c
b’			MKR-TRK	1.0	kHL
REF	48 8 dBrn”	AS 10 dB	37	57	dmn”
PEAK					User
					Menus
LOG
10
dB/					pKEE
					ON	OFF
					%	AM
					ON	OFF
						TOI
					ON m
WA	SB
SC	FC				Power

CORR	Me”U
	FFT
	Menu

Figure 5.32. N dB Bandwidth Measurement

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