Wavecom W40PC, Manual

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WAVECOM Decoders v6.15 W40PC, W41PC, W51PC Advanced Topics
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BIT CORRELATION
The " Bit Correlation " and " Bit Length " analysis tools serve the measurement of bit length.
The "Bit Length" analysis relies on a statistical evaluation of many individual measurements,
whereas the "Bit Correlation” function displays the V1 data graphically.
The data of the "Bit Correlation" is purely sampled and displayed with respect to time. Thus
pulse and tone duration lengths as well as bit bias may be measured. The "Bit Correlation"
analysis also allows the accurate determination of baud rates in the case of asynchronous
systems with bit errors and propagation dependent distortions.
The time duration of a video line and thus the display resolution is set with the sliders "
Time
per Line ". The range is 20,000
µ
s (0.02 s) to 10,000,000
µ
s (10 s) per graphical line and
sampling takes place in steps of 14
µ
s. One graphical display line corresponds to the preset
time.
Selecting the "
Start/Stop
" button controls the effective data sampling.
By moving the mouse cursor a text field is displayed. The value of the positioned segment is
continuously displayed in the time unit "
µ
s" and the baud rate unit "Bd" with the graphical
cursor. The graphical representation of V1 polarity (mark or space) corresponds to the value of
the displayed time and the converted baud rate.
Also the correlation can be determined by using the " Bit Correlation ". The setting of time
unit per line in "Time per Line" is together with the baud rate the preset values for the
correlation.
The following example shows a correlation of 111 bits. The baudrate is 228.66 baud. The
calculation of the total system cycle length thus is (1/228.66) x 111 = 0.4854369s.