
ET User’s Guide
5-13
Optimizing Measurements
Reducing Trace Noise
To Eliminate Receiver Spurious Responses
Spurious responses are undesirable signals that result from various
internal mixing products.
The analyzer has two features to eliminate spurious responses. Both
features shift the frequency of the spur without changing the RF output
frequency. They shift the spur by changing frequencies internal to the
analyzer that mix to produce the RF frequency. The features are:
• dither
• spur avoid
Dither is usually most effective for narrow frequency span
measurements (generally <15 MHz), as explained in the following
paragraph. If dither does not eliminate visible spurs, use spur avoid
instead.
Dithering to Shift
Spurs
Dither shifts all spurs by a small amount once, thus it imposes no sweep
time penalty. But some spurs occurring within the measured frequency
band may not be shifted out of band, and others may be shifted in.
Therefore, dither is most effective for narrowband measurements with a
user-defined measurement calibration. To activate dithering:
1.
Press
.
2. Make a user-defined measurement calibration. Refer to
“Calibrating for Increased Measurement Accuracy,”
for calibration
procedures.
CAUTION
The measurement calibration must be performed with the same spur
avoid option used in the measurement or your results may be invalid.
Activating Spur
Avoidance
When you activate spur avoidance, the analyzer sweeps to a point before
a spur, stops the sweep, shifts the spur, sweeps through the spur
location, then shifts the spur back and continues the sweep. The
analyzer determines which spurs need to be avoided with an algorithm
based on frequencies, number of points, sweep time, and system
bandwidth.
MENU
Spur Avoid Options Dither
Summary of Contents for HP 8712ET
Page 8: ...viii ET User s Guide ...
Page 17: ...ET User s Guide 1 1 1 Installing the Analyzer ...
Page 34: ...1 18 ET User s Guide Installing the Analyzer Preventive Maintenance ...
Page 35: ...ET User s Guide 2 1 2 Getting Started ...
Page 52: ...2 18 ET User s Guide Getting Started Performing the Operator s Check ...
Page 53: ...ET User s Guide 3 1 3 Making Measurements ...
Page 118: ...3 66 ET User s Guide Making Measurements Measuring Impedance Magnitude ...
Page 119: ...ET User s Guide 4 1 4 Using Instrument Functions ...
Page 143: ...ET User s Guide 4 25 Using Instrument Functions Using Markers Figure 4 15 Delta Marker Mode ...
Page 149: ...ET User s Guide 4 31 Using Instrument Functions Using Limit Testing Figure 4 16 Limit Lines ...
Page 207: ...ET User s Guide 5 1 5 Optimizing Measurements ...
Page 226: ...5 20 ET User s Guide Optimizing Measurements Measuring Devices with Long Electrical Delay ...
Page 227: ...ET User s Guide 6 1 6 Calibrating for Increased Measurement Accuracy ...
Page 266: ...6 40 ET User s Guide Calibrating for Increased Measurement Accuracy Checking the Calibration ...
Page 267: ...ET User s Guide 7 1 7 Front Rear Panel ...
Page 292: ...7 26 ET User s Guide Front Rear Panel Line Module ...
Page 293: ...ET User s Guide 8 1 8 Hardkey Softkey Reference ...
Page 395: ...ET User s Guide 9 1 9 Specifications ...
Page 397: ...ET User s Guide 9 3 Specifications System Performance ...
Page 443: ...ET User s Guide 10 1 10 Safety and Regulatory Information ...
Page 449: ...ET User s Guide 10 7 Safety and Regulatory Information Regulatory Information ...
Page 450: ...10 8 ET User s Guide Safety and Regulatory Information Regulatory Information ...
Page 451: ...ET User s Guide 11 1 11 Factory Preset State and Memory Allocation ...