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Agilent Technologies N9010A, Manual

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Agilent Technologies N9010A Manual Download Page 43

Chapter 5

43

Spectrum Emission Mask Measurements

Troubleshooting Hints

Troubleshooting Hints

This spectrum emission mask measurement can reveal degraded or 
defective parts in the transmitter section of the unit under test. The 
following examples are those areas to be checked further.

• Faulty DC power supply control of the transmitter power amplifier.

• RF power controller of the pre-power amplifier stage.

• I/Q control of the baseband stage.

• Some degradation in the gain and output power level of the amplifier 

due to the degraded gain control or increased distortion, or both.

• Some degradation of the amplifier linearity or other performance 

characteristics.

Power amplifiers are one of the final stage elements of a base or mobile 
transmitter and are a critical part of meeting the important power and 
spectral efficiency specifications. Since spectrum emission mask 
measures the spectral response of the amplifier to a complex wide band 
signal, it is a key measurement linking amplifier linearity and other 
performance characteristics to the stringent system specifications.

Summary of Contents for N9010A

Page 1: ...nt X Series Signal Analyzer N9079A TD SCDMA with HSPA 8PSK Measurement Application Measurement Guide This manual provides documentation for the following X Series Analyzers MXA Signal Analyzer N9020A...

Page 2: ...ent prime contract or sub contract Software is delivered and licensed as Commercial computer soft ware as defined in DFAR 252 227 7014 June 1995 or as a commercial item as defined in FAR 2 101 a or as...

Page 3: ...hall pay shipping charges to return the product to Buyer However Buyer shall pay all shipping charges duties and taxes for products returned to Agilent Technologies from another country Where to Find...

Page 4: ......

Page 5: ...easurement Results 26 4 Power vs Time Measurements Configuring the Measurement System 30 Setting the BTS Example 31 Measurement Procedure 32 Measurement Results 34 Troubleshooting Hints 36 5 Spectrum...

Page 6: ...Measurement System 84 Setting the BTS Example 86 Measurement Procedure 87 Measurement Results 88 12 Monitor Spectrum Measurements Configuring the Measurement System 90 Setting the BTS Example 91 Measu...

Page 7: ...Contents 7 Waveform Signal Envelope Views of I only or Q only 106...

Page 8: ...8 Contents...

Page 9: ...SK to select the TD SCDMA mode For information specific to individual measurements see the sections at the page numbers below Transmit Power Measurements on page 13 ACP Measurements on page 21 Power v...

Page 10: ...urement setups in the mode to the factory default parameters To preset the parameters that are specific to an active selected measurement press Meas Setup Meas Preset This returns all the measurement...

Page 11: ...apply to this measurement 3 Select and Set Up a View of the Results Press View Display Select a display format for the current measurement data Depending on the mode and measurement selected other gr...

Page 12: ...12 Chapter1 Making TD SCDMA with HSPA 8PSK Measurements Setting Up and Making a Measurement...

Page 13: ...BTS a mobile station MS a repeater or a power amplifier PA This test measures the average RF power present in the channel There are three methods to determine the power level At or above a specified t...

Page 14: ...the equipment as shown Figure 2 1 Transmit Power Measurement System 1 Using the appropriate cables attenuator and adapters connect the output signal of the BTS to the RF input of the analyzer 2 Conne...

Page 15: ...BTS and the system controller set up a call using loopback mode for the BTS to transmit the RF power as follows Frequency 2 0 GHz Output Power 20 dBm Carrier Number 1 Switching Point 3 Scramble Code 0...

Page 16: ...t Power measurement Step 9 Press Meas Setup to check the keys available to change the measurement parameters from the default condition To change the algorithm to measure the power press Meas Method a...

Page 17: ...val and increase the Threshold Lvl until a valid result is displayed For more details about changing measurement parameters see N9079A TD SCDMA with HSPA 8PSK User s and Programmer s Reference If you...

Page 18: ...on the left of the text window and on the right under the heading Current Data Output Pwr If averaging is turned off the two values will be the same When you turn averaging on the left Output Power i...

Page 19: ...the default Burst Width is inappropriate to perform a measurement it s recommended to increase the Meas Interval and Threshold Lvl or to manually enter the desired Burst Width value Figure 2 3 Transm...

Page 20: ...ower can lead to poor coverage and intermittent service for phone users Out of specification power measurements indicate a fault usually in the power amplifier circuitry They can also provide early in...

Page 21: ...r station BTS a mobile station MS a TD SCDMA repeater or a power amplifier PA ACP is a measurement of the amount of interference or power in an adjacent frequency channel The results are shown as a ba...

Page 22: ...shown Figure 3 1 Adjacent Channel Power Measurement System 1 Using the appropriate cables attenuator and adapters connect the output signal of the BTS to the RF input of the analyzer 2 Connect a BNC c...

Page 23: ...nd the system controller set up a call using loopback mode for the BTS to transmit the RF power as follows Frequency 2 0 GHz Output Power 20 dBm Carrier Number 1 Switching Point 3 Scramble Code 0 Tabl...

Page 24: ...rence frequency by pressing Meas Setup Carrier Setup Ref Carrier and enter the carrier number to be referenced and pressing Ref Car Freq and enter the carrier frequency NOTE When the number of carrier...

Page 25: ...Chapter 3 25 ACP Measurements Measurement Procedure Messages Guide...

Page 26: ...er offset channel power levels are displayed in both absolute and relative readings See Figure 3 2 Figure 3 2 ACP Bar Graph View Default Press View Display and toggle the Bar Graph key to Off to see t...

Page 27: ...Chapter 3 27 ACP Measurements Measurement Results Figure 3 4 shows a ACP measurement example with 12 carriers Figure 3 4 ACP Multiple Carriers...

Page 28: ...28 Chapter3 ACP Measurements Measurement Results...

Page 29: ...measurement on a TD SCDMA base transceiver station BTS a TD SCDMA repeater or a power amplifier PA Good PvT measurement results verify that the transmitter output power has the correct amplitude shap...

Page 30: ...the equipment as shown Figure 4 1 Pwr vs Time Measurement System 1 Using the appropriate cables adapters and attenuator connect the output signal of the BTS to the RF input of the analyzer 2 Connect...

Page 31: ...n station simulator and the system controller set up a call using loopback mode for the BTS to transmit the RF power as follows Frequency 2 0 GHz Output Power 20 dBm Carrier Number 1 Switching Point 3...

Page 32: ...o perform the measurement once NOTE Power vs Time measurement is set in the Single sweep mode Because of the switching of the Preamp state from On to Off performing Power vs Time measurements in the C...

Page 33: ...sing SPAN X Scale Ref Value 100 ms Scale Div 5 ms and press Restart or Single to perform the measurement once Pressing View Display you can turn on any of the following lines Trigger Line white Burst...

Page 34: ...n Power is displayed on the left of the text window If Meas Interval is set to 2 or above Burst Width will be displayed on the right and the Avg Pwr and Slot Width of the each active timeslot are show...

Page 35: ...Chapter 4 35 Power vs Time Measurements Measurement Results Figure 4 2 shows the Power vs Time zoomed in window Figure 4 4 Power vs Time Zoom in Ref Value 105 s Scale Div 3 s...

Page 36: ...r4 Power vs Time Measurements Troubleshooting Hints Troubleshooting Hints If a transmitter fails the Power vs Time measurement this usually indicates a problem with the units output amplifier or level...

Page 37: ...BTS a TD SCDMA repeater or a power amplifier PA SEM compares the total power level within the defined carrier bandwidth and the given offset channels on both sides of the carrier frequency to levels...

Page 38: ...ment as shown Figure 5 1 Spectrum Emission Mask Measurement System 1 Using the appropriate cables adapters and attenuator connect the output signal from the BTS to the RF input port of the analyzer 2...

Page 39: ...ssion station simulator and the system controller set up a call using loopback mode for the BTS to transmit the RF power as follows Frequency 2 0 GHz Output Power 20 dBm Carrier Number 1 Switching Poi...

Page 40: ...Step 7 Press FREQ Channel 2 GHz to set the center frequency to 2 GHz Step 8 Press Meas Spectrum Emission Mask to initiate the Spectrum Emission Mask measurement Step 9 Press Meas Setup to check the ke...

Page 41: ...he absolute peak power levels and margins from limit lines which correspond to the frequency bands on both sides of the reference channel Figure 5 2 SEM Total Power Ref Abs Pwr Freq view Figure 5 3 sh...

Page 42: ...nts Measurement Results Figure 5 4 shows the reference PSD and the integrated power levels and margins from limit lines which correspond to the frequency bands on both sides of the reference channel F...

Page 43: ...ge Some degradation in the gain and output power level of the amplifier due to the degraded gain control or increased distortion or both Some degradation of the amplifier linearity or other performanc...

Page 44: ...44 Chapter5 Spectrum Emission Mask Measurements Troubleshooting Hints...

Page 45: ...ious emission measurement on a TD SCDMA base transceiver station BTS a TD SCDMA repeater or a power amplifier PA This measurement identifies and determines the power level of spurious emissions in cer...

Page 46: ...as shown Figure 6 1 Spurious Emission Measurement System 1 Using the appropriate cables adapters notch filter and attenuator connect the output signal of the BTS to the RF input of the analyzer 2 Con...

Page 47: ...ion station simulator and the system controller set up a call using loopback mode for the BTS to transmit the RF power as follows Frequency 2 0 GHz Output Power 20 dBm Carrier Number 1 Switching Point...

Page 48: ...or Category B define the Base Station mandatory spurious emissions limits with the specified frequency ranges For more information see N9079A TD SCDMA with HSPA 8PSK User s and Programmer s Reference...

Page 49: ...yzer scans the band using the specified Range Table settings As each band is swept any signal above the Peak Threshold and has a peak excursion of greater than the Peak Excursion will be added to the...

Page 50: ...oting Hints Troubleshooting Hints If there is a frequency channel dependency in the operating characteristics of a multi carrier power amplifier it might have channel balance problems due to spurious...

Page 51: ...chapter explains how to make the occupied bandwidth measurement on a TD SCDMA base transceiver station BTS a TD SCDMA repeater or a power amplifier PA The instrument measures power across the band and...

Page 52: ...uipment as shown Figure 7 1 Occupied Bandwidth Measurement System 1 Using the appropriate cables adapters and attenuator connect the output signal of the BTS to the RF input of the analyzer 2 Connect...

Page 53: ...ion station simulator and the system controller set up a call using loopback mode for the BTS to transmit the RF power as follows Frequency 2 0 GHz Output Power 20 dBm Carrier Number 1 Switching Point...

Page 54: ...Press More Gate Source and select the desired gate source External 1 If no measurement is performed and only a symbol of yellow displays on the top right of the screen you need to check the gate setti...

Page 55: ...ter with 30 kHz bandwidth and the Measure span is 4 8 MHz which is centered on channel center frequency and compliant with 3GPP standard Transmit Freq Error The result is the transmit frequency error...

Page 56: ...Any distortion such as harmonics or intermodulation for example produces undesirable power outside the specified bandwidth Shoulders on either side of the spectrum shape indicate spectral regrowth and...

Page 57: ...ower Statistics Complementary Cumulative Distribution Function Power Stat CCDF measurement on a TD SCDMA base transceiver station BTS a TD SCDMA repeater or a power amplifier PA Power Stat CCDF curves...

Page 58: ...System 1 Using the appropriate cables adapters and attenuator connect the output signal of the BTS to the RF input of the analyzer 2 Connect a BNC cable between the frequency reference port of the BTS...

Page 59: ...Chapter 8 59 Power Statistics CCDF Measurements Configuring the Measurement System Figure 8 2 Code Domain Power Measurement System Baseband...

Page 60: ...sion station simulator and the system controller set up a call using loopback mode for the BTS to transmit the RF power as follows Frequency 2 0 GHz Output Power 20 dBm Carrier Number 1 Switching Poin...

Page 61: ...evice to toggle the device to BTS Step 6 Press Meas Power Stat CCDF to initiate the power statistics CCDF measurement Step 7 Press Trigger to select the appropriate trigger source External 1 If no mea...

Page 62: ...62 Chapter8 Power Statistics CCDF Measurements Measurement Results Measurement Results The CCDF measurement result looks similar to Figure 8 3 Figure 8 3 Power Statistics CCDF Measurement...

Page 63: ...ontribute in setting the signal power specifications for design criteria for systems amplifiers and other components For example it can help determine the optimum operating point to adjust each code t...

Page 64: ...64 Chapter8 Power Statistics CCDF Measurements Troubleshooting Hints...

Page 65: ...explains how to make the modulation accuracy composite EVM measurement on a TD SCDMA base transceiver station BTS a TD SCDMA repeater or a power amplifier PA Modulation accuracy is the ratio of the co...

Page 66: ...e equipment as shown Figure 9 1 Modulation Accuracy Measurement System 1 Using the appropriate cables adapters and attenuator connect the output signal of the BTS to the RF input of the analyzer 2 Con...

Page 67: ...Accuracy Composite EVM Measurements Configuring the Measurement System Units with option BBA can also make Baseband I jQ measurements Connect the equipment as shown Figure 9 2 Code Domain Power Measu...

Page 68: ...ansmission station simulator and the system controller set up a call using loopback mode for the BTS to transmit the RF power as follows Frequency 2 0 GHz Output Power 20 dBm Carrier Number 1 Switchin...

Page 69: ...te the modulation accuracy composite EVM measurement Step 8 Press FREQ Channel 2 GHz to set the center frequency to 2 GHz Step 9 Press Meas Setup to check the keys available to change the measurement...

Page 70: ...uld look similar to Figure 9 3 The modulation constellation is shown along with summary data for Rho EVM Peak Code Domain Error and phase and magnitude errors Figure 9 3 Modulation Accuracy I Q Measur...

Page 71: ...hows a combination view of the magnitude error phase error and EVM graph windows Figure 9 5 Modulation Accuracy Measurement I Q Error View Figure 9 6 shows a combination view of the captured data trac...

Page 72: ...ter can also create distortion that causes unacceptably high phase error In a real system a poor phase error will reduce the ability of a receiver to correctly demodulate the received signal especiall...

Page 73: ...make a code domain measurement on a TD SCDMA base transceiver station BTS a TD SCDMA repeater or a power amplifier PA Code Domain measurements provide the power data and error data for an individual c...

Page 74: ...equipment as shown Figure 10 1 Code Domain Power Measurement System RF 1 Using the appropriate cables adapters and attenuator connect the output signal of the BTS to the RF input of the analyzer 2 Con...

Page 75: ...Code Domain Measurements Configuring the Measurement System Units with option BBA can also make Baseband I jQ measurements Connect the equipment as shown Figure 10 2 Code Domain Power Measurement Sys...

Page 76: ...station simulator and the system controller set up a call using loopback mode for the BTS to transmit the RF power as follows Frequency 2 0 GHz Output Power 20 dBm Carrier Number 1 Switching Point 3 S...

Page 77: ...HSPA 8PSK Enable to enable HSPA 8PSK function NOTE If you don t install Option N9079A 2FP HSPA 8PSK Enable is grayed out Step 8 Press Mode Setup Demod to change the demodulation parameters In order to...

Page 78: ...rovides a combination view of the code domain power symbol power I Q symbol polar vector and the summary data Demod Bits provides a combination view of the graphs for the code domain power and symbol...

Page 79: ...d with a text window below it The text window shows the total power level along with the relative power levels of the various channels Figure 10 3 Code Domain Measurement CDP Graph Metrics View Figure...

Page 80: ...ors powers of the signal and the channel Figure 10 5 Code Domain Measurement Result Code Domain Quad View Figure 10 6 shows a combination view of the magnitude error vs symbol phase error vs symbol an...

Page 81: ...set parameters The Demod Bits View displays the same Code Domain Power and Symbol Power windows as the Code Domain Quad View shown in Figure 10 6 The demodulated bit stream displayed is the data conta...

Page 82: ...I Q modulator of the unit under test UUT These will be analyzed by the code domain measurements along with the QPSK EVM measurements and others Poor phase error indicates a problem at the I Q baseban...

Page 83: ...ents This chapter explains how to make a waveform time domain measurement The measurement of I and Q modulated waveforms in the time domain enables you to see the voltages which comprise the complex m...

Page 84: ...t the equipment as shown Figure 11 1 Transmit Power Measurement System 1 Using the appropriate cables adapters and attenuator connect the output signal of the BTS to the RF input of the analyzer 2 Con...

Page 85: ...veform Time Domain Measurements Configuring the Measurement System Units with option BBA can also make Baseband I jQ measurements Connect the equipment as shown Figure 11 2 Code Domain Power Measureme...

Page 86: ...ssion station simulator and the system controller set up a call using loopback mode for the BTS to transmit the RF power as follows Frequency 2 0 GHz Output Power 20 dBm Carrier Number 1 Switching Poi...

Page 87: ...ger settings You need the correct trigger signal to make the IQ Waveform measurement Step 8 Press FREQ Channel 2 GHz to set the center frequency to 2 GHz Step 9 Press View Display to select the desire...

Page 88: ...esults Measurement Results Figure 11 3 shows the IQ Waveform measurement result in RF Envelope view and Figure 11 4 shows IQ Waveform view Figure 11 3 Monitor Spectrum Measurement RF Envelope view Def...

Page 89: ...a TD SCDMA base transceiver station BTS a TD SCDMA repeater or a power amplifier PA This measurement shows a spectrum domain of the signal providing you a quick and convenient means of looking at the...

Page 90: ...e equipment as shown Figure 12 1 Transmit Power Measurement System 1 Using the appropriate cables adapters and attenuator connect the output signal of the BTS to the RF input of the analyzer 2 Connect...

Page 91: ...on station simulator and the system controller set up a call using loopback mode for the BTS to transmit the RF power as follows Frequency 2 0 GHz Output Power 20 dBm Carrier Number 1 Switching Point...

Page 92: ...ht of the screen you need to check the gate settings You need the correct gate signal to make the Monitor Spectrum measurement Step 7 Press FREQ Channel 2 GHz to set the center frequency to 2 GHz Step...

Page 93: ...Chapter 12 93 Monitor Spectrum Measurements Measurement Results Measurement Results Figure 12 2 shows the Monitor Spectrum measurement result Figure 12 2 Monitor Spectrum Measurement...

Page 94: ...94 Chapter12 Monitor Spectrum Measurements Measurement Results...

Page 95: ...95 13 Using Option BBA Baseband I Q Inputs...

Page 96: ...the measurements that can be made using Baseband I Q inputs Table 13 1 BBIQ Supported Measurements vs Mode Mode Measurements GSM IQ Waveform GMSK Phase Freq EDGE EVM 802 16 OFDMA IQ Waveform Power St...

Page 97: ...the I and Q Setup softkey menus The system supports a variety of input passive probes as well as the Agilent 1153A active differential probe using the infinimax probe interface NOTE To avoid duplicati...

Page 98: ...Z C Input a Skew value in seconds D Set up the I Probe by pressing I Probe a Select probe Attenuation b Calibrate the probe Press Calibrate to start the calibration procedure Follow the calibration p...

Page 99: ...on BBA Baseband I Q Inputs provides the ability to analyze baseband I Q signal characteristics of mobile and base station transmitters This option may be used only in conjunction with the following mo...

Page 100: ...r out of phase by 180 degrees Measurements using balanced signals can have a higher signal to noise ratio resulting in improved accuracy Noise coupled into each conductor equally in a common mode to b...

Page 101: ...rm baseband I Q refers to signals that are the fundamental products of individual I Q modulators before the I and Q component signals are combined and before upconversion to IF or RF frequencies In re...

Page 102: ...ency error magnitude and phase errors Code domain analysis including code specific metrics CCDF of Single sideband SSB metrics for assessing output quality Basic analysis of I and Q signals in isolati...

Page 103: ...Chapter 14 103 Baseband I Q Inputs Option BBA Measurement Concepts Why Make Measurements at Baseband...

Page 104: ...requency rejection modes In addition a wide range of offset voltages and probe attenuation accessories are supported at the probe interface The active probe has the advantage that it does not signific...

Page 105: ...ical connections are different mechanically not electrically Refer to the current Agilent probe data sheet for specific information regarding frequency of operation and power supply requirements Table...

Page 106: ...pectrum display of I only or Q only signals use the Complex Spectrum measurement capability in IQ Analyzer Basic Mode I only and Q only Spectrum views are conventional displayed with 0 Hz at the left...

Page 107: ...Chapter 14 107 Baseband I Q Inputs Option BBA Measurement Concepts Baseband I Q Measurement Views measure an I only or Q only waveform directly...

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