Anrtisu Cell Master MT8212B, User Manual, Page: 227 / 294

For Over The Air (OTA) measurements, the channel power will vary as the signal path
from the transmitter to receiver varies.
Freq Error
Frequency error is the difference between the received center frequency and the specified
center frequency. This is only as accurate as the frequency reference used and is typically
only useful with a good external frequency reference.
Rho
Estimated rho is a measure of modulation quality and measures the amount of power cor-
rectly transmitted. An estimated rho of 1.0 indicates a perfect signal. The standard requires
>0.912, and common measurements are >0.94. Due to environmental factors, estimated rho
values are typically poor (<0.9) when measured over the air, and are usually useful only
when connected to a base station.
Noise Floor
The average power in the unused Walsh codes displayed in CDP and OTA measurement
displays.
Tau
The timing offset, or the difference in time between when the PN sequence (or short code)
restarts, and when the PN sequence should restart. A base station needs to be aligned in
time to an absolute reference such as GPS. This cannot be measured if the PN search is set
to
No Trigger
.
Note that during OTA measurement, Tau increases as the Cell Master gets farther from the
transmitter due to the finite speed of light. If the Cell Master is connected to the base sta-
tion, Tau of 10 m s or less is specified, and 5 m s is typical. If the timing error becomes too
large, mobiles may have trouble when being handed off to this particular base station.
Ec/Io
The pilot power compared to the total channel power. Displayed in text only and OTA mea-
surement displays.
Carrier FT
Carrier Feedthrough measures the amount of unmodulated signal that is leaking through the
transmitter and is displayed in a text only display.
PN Scan (available only with Option 33)
The strongest six PNs received are displayed. The length of the bar represents the relative
strength in the channel. To the right of the bar is displayed the power of that pilot compared
to the total channel power (Ec/Io). To the left of the bar is displayed the PN number of that
pilot. This graph is not meaningful if the PN search is set to
No Trigger
.
Multipath (available only with OTA- Option 33)
The length of the bar represents the relative strength in the channel. To the right of the bar
is displayed the power of that signal compared to the total channel power. To the left of the
bar is displayed the timing error (Tau).
Pilot Dominance (available only with OTA - Option 33)
The strength of the strongest pilot compared to the next strongest pilot in the same channel.
This should be >10 dB to make good measurements.
Chapter 13 CDMA Measurement
13-5