Metrics Provided by the W-CDMA or W-CDMA (with HSDPA) Analyzer
This section contains descriptions of the individual W-CDMA or W-CDMA (with HSDPA) transmitter metrics in the Metrics view of the screen. For information on expected result values and possible causes of error if the expected results are not met, see "Interpretation of Measurement Results"
Frequency
Frequency is the selected transmitter operating frequency entered by you (or calculated from the channel number entered by you).
Freq Error (Frequency Error)
Frequency error, as set up in Controls, is the frequency difference between your transmitter's actual center frequency and the frequency (or channel) you entered.
Scramble Code
The Scrambling Code being measured (manual or auto). In W-CDMA or W-CDMA (with HSDPA), each Access Network (or BTS) output signal is scrambled by multiplying each of its data channels by a unique pseudo-noise (PN) code. In the W-CDMA specifications, this is referred to as a Scrambling Code.
Noise Floor
Noise Floor is the average power level of all the inactive channels.
Threshold
Threshold is the active channel threshold level and is an advanced setting that can be set to indicate which code channels are considered active. (For more information, see "Setting the Active Channel Threshold Level and Auto Threshold Level")
EVM Pilot and EVM Comp (Pilot and Composite Error Vector Magnitude)
EVM is the measure of signal quality specified as a percent of noise to pure signal. It is the difference between the measured waveform and the theoretical modulated waveform (the error vector). EVM metrics are used to measure the modulation quality of a transmitter. The 3GPP standard requires the Composite EVM not to exceed 17.5% for normal W-CDMA (defined as Test Models 1 and 4), and not to exceed 12.5% in the case of 16QAM HSDPA (defined as Test Model 5).
PCDE (Peak Code Domain Error)
PCDE takes the noise and projects the maximum impact it will have on all OVSF codes. PCDE is the maximum value for the code domain error for all codes (both active and inactive).
In W-CDMA or W-CDMA (with HSDPA), specifically to address the possibility of uneven error power distribution, the EVM measurement has been supplemented with PCDE. The 3GPP standard requires the PCDE not to exceed -33 dB at a spreading factor of 256, but the Conformance Test adds in a Test Tolerance of 1dB. This gives a Conformance Limit for Peak Code Domain Error of -32dB at a spreading factor of 256.
Carr Feedthru or Carr FT (Carrier Feedthrough)
Carrier Feedthrough is a result of the RF carrier signal feeding through the I/Q modulator and riding on the output circuitry without being modulated.
Chan Pwr (Channel Power)
Channel Power is the integrated power within a defined bandwidth. For W-CDMA or W-CDMA (with HSDPA) the channel bandwidth is 3.84 MHz. Channel Power measures the power the base station is transmitting across the entire 3.84 MHz W-CDMA or W-CDMA (with HSDPA) channel.
CPICH (Common Pilot Channel)
Common Pilot Channel (CPICH) is the channel that carries the scrambling code. The CPICH metric reports the power in this channel in dBc. By default, the CPICH Limits are set to Off. If you set CPICH Limits On, the default upper limit value is 0 dBc, and the lower limit value is -20 dBc.
NOTE: The CPICH default limits are set at a level suitable for catching only gross errors when field testing live signals. To perform conformance testing, you will need to set the limits to your own specifications. Conformance testing for Test Model 2 (TM2), for example, requires that the CPICH limits are set to ±2.9 dB, that is, to -7.1 dB and -12.9 dB with a -10 dBc signal.
Control Channel Delta Powers
The last column on the far right of the Metrics view shows the relative powers of the five control channels relative to the Common Pilot Channel. For example, P-CCPCH is the amplitude difference between the CPICH and the P-CCPCH. In W-CDMA or W-CDMA (with HSDPA) systems, the transmit power of all the control channels can be set at different values relative to the CPICH. the five control channel D power metrics are: