Tektronix 2714 User Manual page 257

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average noise by pressing [VID FLTR)]). It then corrects the measured
value for the difference between average and RMS amplitudes. More
corrections are added for the effects of log amplification and to ac-
count for the equivalent noise bandwidth of the resolution bandwidth
filter not being exactly 5 MHz. The resulting noise is then normalized to
the specified bandwidth.
Now turn off the markers and the video filter.
Measuring Carrier-to-Noise Ratios
To demonstrate the carrier-to-noise (C/N) ratio feature of the 2714, we
will measure the calibrator-to-27 14-noise-floor ratio in a 5 MHz
bandwidth. However, you are more likely to measure a carrier peak to
system noise ratio, but the technique is the same.
Turn on the calibrator. Then call up the Application menu, and select
the Setup Table. Choose item 1, NORM BW FOR C/N, and again enter
5 MHz for the noise bandwidth for the carrier-to-noise (C/N) measure-
ment. Return to the Application menu and select item 1 to turn on the
The spectral display reappears with the fixed marker on top of the
100 MHz signal peak (the 2714 places the fixed marker on the signal
peak nearest the center of the screen in the C/N made). The moveable
marker appears 1 division from the left screen edge.
Reposition the moveable marker 50 MHz above the signal.
The moveable marker is initially positioned only to clearly
separate it from the fixed marker. You must place the noise
marker at the frequency where you want the noise mea-
The first two items in the right on-screen column read approximately
The reading may vary slightly. You will also receive the NOISE LEVEL
LESS THAN 2DB warning.
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