HP 8591C Manuel d'utilisateur télécharger pdf (Page 167)

100

101

Resolving

Small

Signals

Hidden

Large

Signals

Using

the

Resolution

Bandwidth

Function

When dealing with resolution of signals that are not equal in amplitude, you

must consider the shape of the IF filter as well as its 3

bandwidth. The

shape of the filter is defined by the shape factor, which is the ratio of the

bandwidth to the 3

bandwidth. (Generally, the IF lilters in this

spectrum analyzer have shape factors of 15: 1 or less.) If a small signal is

too close to a larger signal, the smaller signal can be hidden by the skirt of

the larger signal. To view the smaller signal, you must select a resolution

bandwidth such that k is less than a. See Figure 4-3.

Figure 4-3. Resolution Bandwidth Requirements for Resolving Small Signals

The separation between the two signals must be greater than half the filter

width of the larger signal at the amplitude level of the smaller signal.

Example: Resolve two input signals with a frequency separation of 200

kHz

and an amplitude separation of 60

dB.

1. To obtain two signals with a 200

kHz

separation, connect the equipment

as shown in the previous section,

“Resolving Signals of Equal Amplitude

Using the Resolution Bandwidth Function.

))

2. Set the center frequency to 300 MHz and the span to 2 MHz: press

FREQUENCY)

300 (MHz), then

ISPAN]

3. Set the source to 300.2 MHz, so that the signal is 200

kHz

higher than the

calibration signal. Set the amplitude of the signal to -31

dBmV

(60

below the calibration signal).

4-6

1 2 ... 162 163 164 165 166 167 168 169 170 171 172 ... 549 550

Commentaires sur ces manuels

Pas de commentaire

HP 8591C Manuel d'utilisateur Page 167

Commentaires sur ces manuels

Produits connexes et manuels pour Mesure, test et contrôle HP 8591C