Measuring Signals Near Band Boundaries Using Harmonic Lock - HP 8590 E-Series User Manual

Measuring Signals Near Band Boundaries Using Harmonic Lock

Note
This application should only be performed using an HP 8592L, HP 85933,
HP 85953, or HP 85963.
When measuring signals at or near a band crossing, use the lowest band having a specified
upper frequency limit that will include the signal of interest. See specifications and
characteristics in your calibration guide for your instrument for harmonic band specifications.
Using harmonic lock, and choosing the lowest possible band to analyze a signal, ensures the
best specified measurement accuracy.
To lock onto a specific harmonic, press C-1, Band Lock , BND LOCK ON OFF (so that
ON is underlined), or select a band (see specifications and characteristics in your calibration
guide for your instrument for band specifications). After setting the harmonic lock, only center
frequencies and spans within the frequency range of the harmonic band may be entered. The
span is automatically reduced to accommodate a center frequency specified near the end of the
band 'range.
Example:
1. Connect 100 MHz COMB OUT to the spectrum analyzer input. The HP 85953 does not have
a 100 MHz COMB OUT signal, so it cannot be used for this measurement example. (An
external source must be substituted.)
2. Press [PRESET] and then the following keys:
Band Lock BND LOCK ON OFF (ON)
3. Place a marker on the farthest peak to the left by using the
difference between the two comb teet,h.
You will see three comb teeth on your display. The spectrum analyzer is locked in band 1
and will not allow multiband sweeps. See Figure 3-28.
5. To see a multiband sweep, press the following keys:
Band Lock BND LOCK ON OFF (OFF)
6. Place a marker on the farthest peak to the left by pressing
The marker readout displays the frequency and amplitude difference between the two comb
teeth. See Figure 3-29.
3-26 Making Basic Measurements
key.