Last updated: 2010-03-31
Channel Power Measurement Description
Channel Power Measurement Parameters
Channel Power Measurement Results
The channel power measurement is made on the RF input signal after frequency downconversion and an analog to digital conversion. The actual power measurement is performed by the test set's digital signal processor (DSP).
The channel power measurement is used to measure the following power as defined in TS 34.122 Section 3.1.
Mean Power: The average power measured in one time slot and a bandwidth of at least (1+alpha) times the chip rate. This measurement is intended to only measure the power of TD-SCDMA modulated carrier, which in theory is 100% contained in this bandwidth.
RRC Filtered Mean Power: The averaged power measured in one time slot and with a Root Raised Cosine (RRC) filter with a roll-off factor of alpha=0.22 and a bandwidth equal to the chip rate. In theory, it is 0.246dB below the mean power.
This measurement requires the calibration data of the measurement receiver path gain, which are part of the results of the measurement calibration, see Calibrate Measurements.
Multi-Measurement Count: see Multi-Measurement Count
RRC Filter: The signal can be filtered in the DSP with a root-raised cosine (RRC) filter with a roll-off of 0.22 and a bandwidth equal to the chip rate to comply with 3GPP 34.122 conformance specifications that require RRC filtered power. The filter can also be turned off for conformance specifications requiring a mean power measurement. When the RRC filter is Off , the bandwidth of the channel power measurement is greater than (1+alpha) times the chip rate, where alpha=0.22.
Trigger Arm: see Trigger Arm
Trigger Source: see Trigger Source
Trigger Delay: see Trigger Delay
Time Slot to Measure: see Time Slot to Measure
Manual Power Range Offset: see Manual Power Range Offset
Measurement Timeout: see Measurement Timeout
Integrity Indicator: see Integrity Indicator
Channel Power (in dBm): If Multi-Measurement Count is on, average, maximum and minimum channel power results are displayed on the measurement screen.
The measured signal level is expected to be within 9 dB of the expected power.
Input signal level into the test set's RF IN/OUT connector is between -65 dBm and +28 dBm, in a 1.28 MHz bandwidth
For Non-HSDPA channel type, the frequency of the measured signal should be within 20KHz from the expected receiver frequency; For HSDPA channel type, the frequency of the measured signal should be within 2KHz from the expected receiver frequency.
GPIB Commands: SETup:TCPower, FETCh:TCPower