Campbell Scientific LoggerNet Datalogger Support Software - Manual (Page 215)

Section 6. Network Status and Resolving Communication Problems
The information recorded in the TD-RF Quality Report includes the location of
the maximum and minimum transition point for the T1 and T2 detection
windows and the size, in bytes, of the received test packet.
As has been mentioned, the magnitude of the T1 and T2 transition point
deviations from the center of the detection window is directly related to the
level of noise in the received signal. The level of noise relative to the level of
the desired information in the received signal is known as the Signal to Noise
Ratio (SNR) and is a prime metric of received RF signal quality; the greater the
level of desired information relative to the level of noise in the received signal,
the greater SNR and the greater the quality of the received signal.
The test packet size is significant as an indicator of lost packets. The over the
air (OTA) communications protocol utilized by the RF modems requires that a
1 1 1 1 1 1 1 0 0 0 1 0 0
0 204 102 0 204 102
T1 T1 T1 T2 T1 T1 T1 T2 T2 T2 T1 T2 T1
Composite of all T2 Transitions Composite of all T1 Transitions
MIN MIN MAX MAX
42 144 54 166 242
Demodulated Data Stream
Bit Rate = 3 KHz
1 2 3
TD-RF QUALITY REPORT
1 The total number of Data bytes in the test packet. Dynamically adjusted downward in
response to lost or corrupted packets.
2 The location of the Minimum and Maximum of all T2 bit transition points within the
tolerance window.
For the ideal waveform, bit transitions would occur near the center (point 102) of the
tolerance window. The magnitude of deviation from the center of the window is inversely
proportional to signal quality.
3 The location of the Minimum and Maximum of all T1 bit transition points within the
tolerance window.
4
4 4
0
+V
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