2-8 CDMA Measurement Descriptions CDMA Signal Analyzer
2-16 PN: 10580-00235 Rev. D 3GPP2 MG
Carrier Feedthrough
Carrier Feedthrough measures the amount of unmodulated signal that is leaking through the
transmitter.
Frequency 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 that is used and is
typically only useful with a good quality external frequency reference.
Noise Floor
Noise floor is the average power in the unused Walsh Codes.
Paging Code Power
Paging Code Power is a measure of Page Walsh Code power, displayed in dBm.
Q Paging Power
Q Paging Power is Quick Page Walsh Code 80 power, displayed in dBm.
Rho
Rho is a measure of modulation quality and measures the amount of power that is correctly
transmitted. An rho of 1.0 indicates a perfect signal. The standard requires > 0.912, and
common measurements are > 0.94. Due to environmental factors, rho values are typically
poor (< 0.9) when measured over the air, and are usually useful only when connected to a base
station.
Sync Power
Sync Power is a measure of Sync Walsh Code power, displayed in dBm.
Tau
Tau is the timing error. It is 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 with distance from the transmitter. If the
instrument is connected to the base station, then a Tau of 10 μs or less is specified, and 5 μs is
typical. If the timing error becomes too large, mobiles may have trouble when being handed
off to this particular base station.
Table 2-1. Code Domain Power
Code Channel Color
Pilot Red
Sync Blue
Page Green
Quick Page Purple
IS95 Traffic Yellow
CDMA2000 Traffic Orange
Noise Grey
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