Transmit Power Measurement Description

How is a TXP measurement made?

TXP measurement provides the Burst Power and Estimated Carrier Power measurements for GMSK, 8PSK or 16QAM modulated signals. You can use Burst Capture Range to configure whether a single uplink burst or all uplink bursts in one TDMA frame are measured during the TXP measurement.

• TXP Measurement with Burst Capture Range set to Single

  When Burst Capture Range is set to Single , the TXP measurement measures the Burst Power of a single burst (GMSK modulated) at one capture of the TDMA frame, the TXP measurement supports the multislot configuration of up to 2 uplink bursts, but only the burst specified by the Measurement Burst parameter is measured each time.

  In EGPRS Active Cell and Test modes, An `Unsupported Configuration' message is displayed when using the TXP Measurement with Burst Capture Range set to Single . You should use the EGPRS Transmit Power (ETXP) Measurement instead.

  In order to provide you with a very fast TXP measurement the test set measures the power without synchronizing it to the midamble. The measurement is made with RF amplitude synchronization; therefore, the signal does not need to be demodulated to determine the midamble. This technique is different from the TXP measurement defined in 3GPP 51.010 (formerly ETSI GSM 11.10). (See Burst Synchronization of Measurements ). The power versus time measurement provides a carrier power measurement that is synchronized to the burst's midamble, and conforms to 3GPP 51.010 (formerly ETSI GSM 11.10), section 13.3 and 3GPP 51.010 (formerly ETSI GSM 11.10), section 13.16.2. (See Power versus Time Measurement Description for more details.)

  The TXP measurement can be made on the following types of input signals:

  • A multislot configuration with 1 to 2 uplink normal bursts (GMSK modulated).
  • An access (RACH) burst.
  • A CW signal.

• TXP Measurement with Burst Capture Range set to All

  When Burst Capture Range is set to All , the TXP measurement measures the Burst Power and Estimated Carrier Power of all uplink bursts (either 8PSK or GMSK modulated) at one capture of the TDMA frame. The TXP Measurement can measure both consecutive and non-consecutive uplink bursts depending on the uplink burst configuration state setting:

  • When the uplink burst configuration state is set to OFF, the TXP measurement supports the multislot configuration of up to 6 consecutive uplink bursts in all operating modes.
  • When the uplink burst configuration state is set to ON, the TXP measurement supports the uplink burst configuration of up to 7 non-consecutive uplink bursts in GPRS BCH+PDTCH or EGPRS BCH+PDTCH operation mode. The multislot configuration does not work when the uplink burst configuration state is set to ON, you should use the uplink burst configuration instead. See PDTCH Parameters to see more information about the uplink burst configuration. The Burst Capture Range is set to all and can not be changed in this senario.

  The Burst Power measurement results (with averaging turned on) conform to ETSI GSM 05.05 (Ver 8), section 4. It also conforms with 3GPP 51.010 (formerly ETSI GSM 11.10) if used as part of a type approval system. The Estimated Carrier Power measurement results meet the accuracy requirements for an estimation technique of long term average power as defined in 3GPP 51.010, annex 5.

  The TXP measurement can be made on these types of input signals.

  • A multislot configuration with 1 to 6 consecutive uplink normal bursts (GMSK, 8PSK or 16QAM modulated).
  • An access (RACH) burst.
  • An uplink burst configuration with 1 -7 uplink normal bursts (GMSK, 8PSK or 16QAM modulated) in GPRS BCH+PDTCH or EGPRS BCH+PDTCH operating mode.

See the following table for instructions on how to properly set the Burst Capture Range and how to select the correct measurement.

The TXP measurement is completely controlled by the test set. The power meter used for this measurement is zeroed automatically by the DSP as needed. No temperature dependent calibration is required because temperature compensation in the power detector circuits provide temperature stability.

Operating Consideration

The following table lists the behavior differences for different Burst Capture Range and uplink burst configuration settings.

• You must set the measurement frequency and expected power correctly in order to get the accurate power result of the measured burst when measuring the non-consecutive bursts.
• When measuring the non-consecutive bursts, the first burst in each TDMA frame is assumed as the highest burst.
• When measuring the non-consecutive bursts, the mobile station is required to query whether the hardware of the test set has been armed to accept the input RF signal before transmission. The GPIB command to query the arm state of the test set in the non-consecutive measurement state is INITiate:TXPower:BMEasure:ARMed? .
• The uplink burst configuration is only available when the operating mode is set to GPRS BCH+PDTCH or EGPRS BCH+PDTCH.

Impact on Other Measurements

The TXP measurement can operate concurrently with other measurements when the Burst Capture Range is set to Single or when the Burst Capture Range is set to All and the uplink burst configuration state is set to OFF. However, when the uplink burst configuration state is set to ON, initiating the TXP measurement will cause other running measurements to be closed.

TXP Measurement Parameters

• Arm State

  This parameter is only applicable when the uplink burst state is set to ON. The parameter indicates whether the hardware of the test set has been armed to accept input RF signal.

  The GPIB command to query this parameter is INITiate:TXPower:BMEasure:ARMed? .

• Auto Range to Highest Burst

  This parameter is only applicable when Burst Capture Range is set to All .

  Note, when Burst Capture Range is set to All , you only need to set the expected power for the highest burst, which is called `highest expected power' in the following descriptions. see Expected Power Control for information on how to set the expected power.

  This parameter determines whether the test set ranges its hardware to the highest power of the input bursts or not. If this parameter set to On , the test set ranges its hardware to the highest input burst before the measurement is performed. The specified accuracy can be achieved when the highest input burst is within the range of -30 dB to +3 dB relative to the highest expected power. If this parameter is set to Off , the test set ranges its hardware according to the highest expected power, but the highest input burst must be within the range of -3 dB to +3 dB relative to the highest expected power to achieve the specified accuracy. The figure below illustrates the ranges of the input burst which can achieve the specified accuracy based on the Auto-Ranging to Highest Burst setting.

  Note that the measurement speed will slow down when the Auto Range to Highest Burst parameter is set to ON .

  The GPIB command to set this parameter is SETup:TXPower:RANGe:AUTO .

  The Ranges of the Highest Input Burst

  
• Burst Capture Range

  This parameter determines whether a single uplink burst or all uplink bursts in a multi-slot configuration are measured during the TXP measurement. The default value for this parameter is Single . When Burst Capture Range is set to Single , the TXP measurement measures one burst which is specified by Measurement Burst . When Burst Capture Range is set to ALL , the TXP measurement measures all bursts in one TDMA frame.

  The Burst Capture Range is not available when the Uplink Burst Configuration state is set to ON.

  The GPIB command to set this parameter is SETup:TXPower:BURSt:CAPTure .

• Estimated Carrier Power

  This parameter is only applicable when Burst Capture Range is set to All and the operating mode is Active Cell (EGPRS), EGPRS BCH, EGPRS BCH+PDTCH or EGPRS BCH+TCH+PDTCH .

  This parameter specifies whether the Carrier Power is calculated. The default value for this parameter is On . This parameter is available only in the EGPRS Active cell and the EGPRS Test mode.

  The table below lists the relationship between Estimated Carrier Power State and the Estimated Carrier Power result displayed on front panel or retrieved by GPIB command.

  Estimated Carrier Power State	Modulation Format	Estimated Carrier Power displayed on front panel	Estimated Carrier Power Retrieved by GPIB command
  On	8PSK, 16QAM	Display the Estimated Carrier Power result.	returned Estimated Carrier Power result.
  On	GMSK	Display the Estimated Carrier Power while the result is equal to the Burst Power	The returned result is equal to Burst Power.
  OFF	8PSK, 16QAM	Display ----	Not Available (NAN's are returned)
  OFF	GMSK	Display the Estimated Carrier Power while the result is equal to the Burst Power	The returned result is equal to Burst Power.

  The Estimated Carrier Power is not available when the Uplink Burst Configuration state is set to ON.

  The GPIB command to set this parameter is SETup:TXPower:ECPower:STATe .

• Frame Qualification

  This parameter is only applicable when Burst Capture Range is set to All .

  This parameter is used to determine whether the number of the measured bursts and their modulation formats are correct. When Measurement Frame Qualification is set to On , the measurement checks the number of the measured bursts in a TDMA frame and the modulation format of the input signal. If they don't match the expected value, the samples are discarded and the samplers are re-armed.

  The Frame Qualification is not available when the Uplink Burst Configuration state is set to ON.

  The GPIB command to set this parameter is SETup:TXPower:FRAMe:QUALifier .

• Measurement Burst

  This parameter indicates which burst in the multislot configuration is measured if the user chooses to measure an individual burst by setting Burst Capture Range to SINGle . Measurement Burst is fixed to 1 when only a single uplink timeslot is present. See How Do I Configure the PDTCH Parameters? .

  The GPIB command to set this parameter is CALL:(PDTCH|PDTChannel):MSLot:MEASurement:BURSt .

• Measurement Timeout

  You can set the timeout state and time for this measurement. To set them separately, use SETup:TXPower:TIMeout:STATe to set the timeout state, SETup:TXPower:TIMeout:TIME to set the timeout time; use SETup:TXPower:TIMeout[:STIMe] to set the state and time simultaneously.

• Multi-measurement Count

  You can set Multi-Measurement state and count for the TXP measurement. If Multi-Measurement State is On , Multi-Measurement Count determines how many measurements are to be performed for a measurement request. If Multi-Measurement State is Off , no Multi-Measurement are performed.

  The TXP measurement use the standard Multi-Measurement implementation. Each Multi-Measurement returns the average value, maximum value, minimum value and standard deviation for the number of counts selected. No intermediate results are returned during a Multi-Measurement.

  Multi-Measurement count specifies how many loops are measured for a measurement request.

  To set Multi-Measurement state and count separately, use SETup:TXPower:COUNt:STATe to set the Multi-Measurement state, SETup:TXPower:COUNt:NUMBer to set the Multi-Measurement count; use SETup:TXPower:COUNt[:SNUMber] to set the state and count simultaneously.

• Multi-measurement Count Progress Indicator

  There is a progress indicator displayed on the front panel that shows how many measurements of the total Multi-Measurement count have been made. You can retrieve it using FETCh:TXPower:ICOunt? .

• Trigger Arm

  Trigger arm can be set to Single or Continuous , See Trigger Arm (Single or Continuous) Description for more information.

  Note, during non-consecutive burst measuring with Uplink Burst Configuration State setting to ON, the trigger arm is set to Single and can not be changed.

  The GPIB command to set this parameter is SETup:TXPower:CONTinuous .

• Trigger Delay

  This is the specified time between the trigger event and when the test set begins sampling data. See Trigger Delay Description for more information.

  The GPIB command to set this parameter is SETup:TXPower:TRIGger:DELay .

• Trigger Qualification

  This parameter defines whether the measurement will discard the samples on detection of an idle frame. If this parameter is set to ON , the samples is discarded; If the parameter is set to OFF , the measurement continues to be completed.

  The GPIB command to set this parameter is SETup:TXPower:TRIGger:QUALifier .

• Trigger Source

  Auto triggering is the recommended trigger source for each measurement. This allows the test set to choose the preferred trigger source. See Trigger Source Description . The following table shows the recommended trigger source for the TXP measurement.

  Note, When measuring the non-consecutive bursts, the trigger source will be fixed as RF Rising for the first acquisition of the measurement, then protocol trigger will be used for all the subsequent TDMA frames.

  Recommended Trigger Source

  Operating mode		Recommended Trigger Source
  Active Cell		RF Rise or Protocol for GMSK signals
  		Protocol for 8PSK signals
  Test mode		RF Rise
  CW signal		Immediate

  The GPIB command to set this parameter is SETup:TXPower:TRIGger:SOURce .

TXP Measurement Results

The results returned by the TXP measurement are Burst Power, Estimated Carrier Power and Integrity Indicator. Additionally, average, maximum, minimum and standard deviation of Burst Power and Estimated Carrier Power are returned when the Multi-Measurement state is On .

TXP Measurement Input Signal Requirements

• Single Burst Capture TXP Measurement

  When Burst Capture Range is set to Single , the TXP measurement will complete and be accurate when:

  • The input signal is within +/- 100 kHz of the expected frequency.
  • The level of the input burst is between -30 dBm and +43 dBm.
  • The level of the input burst is within +/-3 dB of the Expected Power.
• Multiple Burst Capture TXP Measurement

  When Burst Capture Range is set to All , the TXP measurement will complete and be accurate when:

  • The input signal is within +/- 100 kHz of the expected frequency.
  • The level of the input burst is between -25 dBm and +30 dBm when measureing the Burst Power of 8PSK modulated bursts.
  • The level of the input burst is between -25 dBm and +33 dBm when measureing the Burst Power of 8PSK modulated bursts.
  • The level of the input burst is between -25 dBm and +37 dBm when measuring the Burst Power of GMSK modulated bursts.
  • The level of the input burst is between -20 dBm and +33 dBm when measuring Estimated Carrier Power.
  • When the Auto Range to Highest Burst parameter is set to OFF :
    • The level of the highest input burst is within +/-3 dB of the Highest Expected Power.
    • The level of all the other input bursts are within +3dB/-30dB of the Highest Expected Power.
  • when the Auto Range to Highest Burst parameter is set to ON :
    • The level of the highest input burst is within +3dB/-30dB dB of the Highest Expected Power.
    • The level of the all other input bursts are within +3dB/-30dB of the Highest Expected Power.

How is an EGPRS transmit power (ETXP) measurement made?

For EGPRS mobiles, ETXP provides a broadband measurement of the average transmitted burst and carrier power of an 8PSK or GMSK modulated signal for a specified burst in a multislot configuration. Multislot configurations with different power levels on each burst are supported. Only one burst which you specify using CALL:(PDTCH|PDTChannel):MSLot:MEASurement:BURSt is measured at a time. You can also control the modulation and coding scheme (either 8PSK or GMSK modulation) used by the data connection to be measured using CALL:(PDTCH|PDTChannel):MCSCheme . Additionally, you can manually control what modulation should be expected for individual bursts using CALL:MODulation[:FORMat]:CONTrol:AUTO . See "Modulation Format Control (EGPRS only)" on page 10 for more information.

The EGPRS radio format allows for all GMSK, all 8PSK or a mixture of GMSK and 8PSK bursts in a multislot configuration. Additionally, when a timeslot supports an 8PSK packet data traffic channel (PDTCH), GMSK modulated control blocks can be inserted. When you specify a burst to measure, the measurement takes samples only from that burst in the multislot configuration. If the modulation is the same as the modulation and coding scheme you have selected or the modulation format you manually specified, the measurement proceeds normally. If the modulation is not the same, the samples are discarded and the measurement is re-armed. The measurement completes when a burst using the same modulation is detected.

Types of Signals ETXP can Measure

The following list summarizes the input signal attributes and mobile station operating modes for making ETXP measurements.Normal GSM TCH burst with the operating mode set to active cell and the serving cell set to EGPRS.

• Two burst multislot configuration comprising two normal PDTCH bursts with the operating mode set to active cell and the serving cell set to EGPRS.
• Single normal PDTCH burst with the mobile station in active cell mode.
• Access (RACH) burst with the mobile station in active cell mode.
• Two burst multislot configuration comprising two normal PDTCH bursts with the mobile station in EGPRS BCH, EGPRS BCH+PDTCH or EGPRS BCH+TCH+PDTCH test mode (no protocol).
• Single normal PDTCH burst with the mobile station in EGPRS BCH, EGPRS BCH+PDTCH or EGPRS BCH+TCH+PDTCH test mode (no protocol).
• Access (RACH) burst with mobile station in EGPRS BCH, EGPRS BCH+PDTCH or EGPRS BCH+TCH+PDTCH test mode (no protocol).

Input Signal Requirements

The ETXP measurement requires the following signal attributes:

• Level is between -30 dBm and +37 dBm (Peak).
• Level within +/-3 dB of the expected input level.
• Input signal is within +/- 100 kHz for GMSK signals and +/- 1 kHz for 8PSK signals of the expected frequency.

Trigger Source

Auto triggering is the recommended trigger source for each measurement. This allows the test set to choose the preferred trigger source. However you may want to select the trigger source. See Recommended Trigger Source Settings