Using The Power Measurement Functions To Make Transmitter Measurements; Occupied Bandwidth And Transmitter Frequency Error - HP 8590 E-Series User Manual

Using the Power Measurement Functions to make Transmitter
Measurements
The power menu provides several powerful transmitter measurement functions that are easy to
use. The measurements include:
Occupied Bandwidth
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Adjacent Channel Power Ratio
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Channel Power
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These transmitter power measurements can be used to measure analog and continuous carrier
digital radios. The transmitted signal can be tones, noise, or a combination of tones and noise,
without affecting the measurement accuracy. The power is measured in an rms way, so that
power and power ratio values are consistent with power meter results.
The signal or signals being measured should be displayed before activating the measurement.
The spectrum-analyzer center frequency should be set to the carrier frequency and the
reference level should be set so that the signal is near the top graticule. A power measurement
may require the user to enter the channel spacing and/or channel bandwidth before activating
the function.
The spectrum analyzer automatically selects all of the other settings for accurate and efficient
measurements. There is also a manual mode where the user selects all of the spectrum-analyzer
settings. The manual mode should be used carefully since it has limitations and requirements
that are necessary to ensure the measurement is accurate.
Power measurements are made continuously, updating at the end of each sweep. This allows
you to make adjustments and see changes as they happen. They can also be made on a single
sweep, providing time to study or record the data.
Note
Some spectrum-analyzer options may be required to make valid measurements,
particularly in narrow bandwidths.
The built-in frequency counter is standard in the HP 859OL, HP 85913,
HP 8592L, HP 85933, HP 85943, HP 8594L, HP 85953, and HP 85963. It is not
available with HP 8590L with Option 713.
The precision frequency reference is available as Option 004 for the HP 85913,
HP 85933, HP 85943, HP 85953, and HP 85963.

Occupied Bandwidth and Transmitter Frequency Error

You often need to confirm a channel's 99% occupied bandwidth. The OCCUPIED BANDWDTH
function does this easily. The user enters the channel spacing and activates the occupied
bandwidth function. Markers show the power bandwidth edges, and the spectrum analyzer
calculates and displays:
The total power in dBm (other units selectable)
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The occupied bandwidth (99% power bandwidth)
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The transmitter frequency error
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The transmitter frequency error is the frequency difference between the midpoint of the power
bandwidth and the spectrum analyzer center frequency.
For special applications you can change the percent power bandwidth from 1% to 99.99% using
the OCC BW % POWER key.
Example: Measure the 99% occupied bandwidth.
Making Measurements 4-43