M a k i n g M e a s u r e m e n t s U s i n g S p e c t r u m A n a l y z e r M a d e
Using the
Use the guidelines in 7Able
Table
Determining Spectrum Analyzer Settings for Viewing a Pulsed RF Signal
Spectrum Analyzer |
| Spectrum | Analyzer | Setting |
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S w e e p T i m e | Set the sweep time to be 401 times greater | Because the gate must be on at least once | ||||||||||||
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| than the pulse repetition interval IPRII: | per trace point, the sweep time has to be | |||||||||||
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| set to the pulse repetition interval times for | |
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| S w e e p | t i m e | > 4 0 1 x | PRI |
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| every point of the trace. IEach trace has | |||||
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| 401 points.) | |
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Gate | Delay | The gate | delay | is | equal | to the | signal delay | The gate delay must be set so that the | ||||||
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| plus half of the pulse width: |
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| gating captures the pulse. If the gate delay | |||||||||
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| is too short or too long, the gating can mist | |
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| G a t e | D e l a y = | S i g n a l D e l a y | + | r/2 | the pulse or include resolution bandwidth | |||||||
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| transient | responses. |
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Gate | Length | The gate | length | is | equal | to | If the gate length is too long, the signal | |||||||
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| pulse | width: |
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| display can include transients caused by the | ||
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| spectrum | analyzer filters. |
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| G a t e | l e n g t h = | r/4 |
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Video | Bandwidth | S e t t h e | v i d e o | b a n d w i d t h t o | a | v a l u e g r e a t e r | T h e v i d e o | b a n d w i d t h m u s t b e w i d e e n o u g h | ||||||
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| than 1 divided by the gate length: | so that the rise times of the video | |||||||||||
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| bandwidth do not attenuate the signal. | |
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| V i d e o | B a n d w i d t h > | gate ,!englh |
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Resolution Bandwidth | Set the resolution bandwidth to a value | The resolution bandwidth must be wide | ||||||||||||
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| greater then 2 divided by the gate delay | enough so that the charging time for the | |||||||||||
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| minus | the signal | delay: |
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| resolution bandwidth filters is less than the | |||||
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| pulse width of the signal. | |
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| R e s o l u t i o n B a n d w i d t h > |
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| G a t e D e l a y - S i g n a l D e l a y |
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