Date:2010-11-17 17:50:13 (8 years 11 months ago)
Author:Werner Almesberger
Commit:66f6ad6f7c37a5be57f139b4735f37bffba12058
Message:usrp/README: described how to perform and evaluate a measurement run

Files: usrp/README (2 diffs)

Change Details

usrp/README
1414Preparing a measurement run
1515---------------------------
1616
17Before measuring the characteristics of an antenne, we need to set up the
17Before measuring the characteristics of an antenna, we need to set up the
1818test environment and obtain a number of filtering parameters. The filters
1919are used to reduce the effect of noise on the measurements and to suppress
2020contamination from other sources.
...... 
149149
150150   The output are three numbers: the average (after eliminating
151151   outliers), the minimum, and the maximum.
152
153
154Performing a measurement run
155----------------------------
156
157The script "fscan" performs 100 scans of the 26 channels used by IEEE
158802.15.4. The frequency scan is the inner loop, so that slow changes
159in environmental parameters (background noise, temperature, etc.) will
160affect the spread of the results over the entire frequency range instead
161of causing seemingly frequency-dependent distortions.
162
163The script is written for a setup that uses a pair of hosts, both
164sharing the same file system.
165
166Usage: fscan out-dir [tx-power]
167
168The output directory must not exist yet. The transmit power is in dBm and
169defaults to 2.6 dBm.
170
171Example: ./fscan testant
172
173The full run takes approximately half an hour.
174
175The results are filtered and averaged by the script "evscan". This script
176contains the filtering parameters obtained in the preparation, described
177above.
178
179Example: ./evscan testant >testant.out
180
181The output is a graph with frequency, average signal strength, minimum
182and maximum. The format is compatible with gnuplot's "with errorbars"
183(or "with errorlines") plot style.
184
185Finally, the results can be plotted with the script "plscan", which uses
186gnuplot to output either in a window or to a PNG file.
187
188Usage: plscan [-o pngfile] file ...
189
190More than one graph can be plotted in the same run. The file name is used
191as the title for each graph. Titles are truncated at the first dot.
192
193Example: ./plscan testant.out

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