HP 8360 Preset, User’s, Mode User, Contents-8

M.

MI--M2Sweep . . . . . . . . . . : . . . . . .

Manual Sweep . . . . . . . . . . . . . . . . .

(MARKER)

. . . . . . . . . . . . . . . . . . . .

MarkerMi . . . . . . . . . . . . . . . . . .

Marker M2 . . . . . . . . . . . . . . . . . .

MarkerM3 . . . . . . . . . . . . . . . . . .

Marker M4 . . . . . . . . . . . . . . . . . .

MarkerM5 . . . . . . . . . . . . . . . . . .

Markers All Off . . . . . . . . . . . . . . .

Measure Corx All . . . . . . . . . . . . . .

Measure Corr Current . . . . . . . . . . . .

Measure Corr Undef . . . . . . . . . . . . .

Meter Adxs . . . . . . . . . . . . . . . . . .

Meter On/Off AM . . . . . . . . . . . . . . .

Meter On/Off FM . . . . . . . . . . . . . . .

@ . . . . . . . . . . . . . . . . . . . . .

ModOut On/Off API . . . . . . . . . . . . . .

ModOut On/Off FM . . . . . . . . . . . . . .

Modulation . . . . . . . . . . . . . . . . . .

Amplitude Modulation . . . . . . . . . . . . .

FMModulation . . . . . . . . . . . . . . . .

Pulse Modulation . . . . . . . . . . . . . . . .

Module Menu . . . . . . . . . . . . . . . . .

Module Select AUTO . . . . . . . . . . . . .

Module Select Front . . . . . . . . . . . . .

Module Select None . . . . . . . . . . . . .

Module Select Rear . . . . . . . . . . . . .

Monitor Menu . . . . . . . . . . . . . . . . .

morenfm.. . . . . . . . . . . . . . . . . .

Mtr Meas Menu . . . . . . . . . . . . . . . .

P.

Peak RF Always . . . . . . . . . . . . . . . .

PeakRFOnce . . . . . . . . . . . . . . . . .

(POWER L E V E L ) . . . . . . . . . . . . . . . . .

POWER(E)

. . . . . . . . . . . . . . . . .

Pawer Offset . . . . . . . . . . . . . . . . .

Power Slope . . . . . . . . . . . . . . . . .

Power Sweep . . . . . . . . . . . . . . . . .

;w)(PRESET) . .- . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . .

Preset Mode Factory . . . ............ . . . .

Preset Mode User . . . . . . ........... . . .

M-l M-l M-3 M-4 M-5 M-5 M-6 M-6 M-7 M-7 M-8 M-8 M-9 M-9 M-10 M-10 M-11 M-12 M-12 M-14 M-17 M-19 M-23 M-24 M-24 M-25 M-26 M-26 M-27 M-28

P-l P-2 P-2 P-5 P-6 P-6 P-7 P-8 P-9 P-10

Contents-8	HP 8360
User’s	Handbook

Contents

SERIAL NUMBERS HP Part No Microfiche Part No Printed in USA November Edition Notice Restricted Rights Legend Certification Warranty Assistance Safety Notes WARNING CAUTION General Safety Considerations nIf this instrument is used in a manner not specified by CAUTION Note PREFACE Instruments Covered By This Manual Figure O-l.Typical Serial Number Label User’s Handbook Organization HP 8360 Series Documentation Typeface Conventions Regulatory Information Manufacturer’s Declaration Notice for Germany: Noise Declaration Declaration of Conformity Manufacturer’s Name: Product Name: Model Numbers: Product Options: Supplementary Information: Instrument MarkingsA Hewlett-PackardSales and Service Offices Contents Contents-2 Contents-3 Contents-4 User’s ASSIGN Page Page Preset Mode User Contents-8 (RECALL) Contents-l0 Contents-l1 Contents-l2 Contents-13 Contents-14 Figures Contents-16 Tables GETTING STARTED Note Equipment Used In Examples Introducing the HP 8360 Series Synthesized Sweepers Getting Started Basic Display Area Figure l-2.Display l-4Getting Started Basic Entry Area Figure l-3.Entry Area Getting Started Basic l-5 CW Operation and Start/Stop Frequency Sweep CW Operation Start/Stop Frequency Sweep Figure 1-4.CW Operation and Start/Stop Frequency Sweep Center Frequency/Span Page Power Level and Sweep Time Page Continuous, Single and Manual Sweep Page Marker Operation Caution 1-14Getting Started Basic Figure 1-6.Marker Operation 8.Select Delta l4kr Ref Saving and Recalling an Instrument State 1-16Getting Started Basic Figure 1-9.Saving and Recalling an Instrument State Getting Started Basic l-17 Power Sweep and Power Slope Page Page Getting Started Advanced Table l-l.Keys Under Discussion in This Section Getting Started Advanced Table l-l Keys Under Discussion in This Section (continued) 1-22Getting Started Advanced Externally Leveling the Synthesizer Figure l-11. ALC Circuit Externally Leveled Hint l-24Getting Started Advanced 100 mV 10 mV DETECTOR INPUT POWER, dBm dBV External Leveling Used With the Optional Step Attenuator l-26Getting Started Advanced Leveling with Power Meters Figure 1-13.Leveling with a Power Meter Getting Started Advanced l-27 Leveling with MM-waveSource Modules Figure 1-15. MM-waveSource Module Leveling Using a Microwave Amplifier Working with Mixers/Reverse Power Effects I-30Getting Started Advanced R F L E V E ATTENUATOR CONTROL 1 0 dB Working with Spectrum Analyzers/Reverse Power Effects 1-32Getting Started Advanced Optimizing Synthesizer Performance Creating and Applying the User Flatness Creating a User Flatness Array Automatically, Example Figure 1-16.Creating a User Flatness Array Automatically 1-34Getting Started Advanced Getting Started Advanced l-35 Creating a User Flatness Array, Example 1-36Getting Started Advanced Figure 1-19.Creating a User Flatness Array Menu l-38Getting Started Advanced Example Figure l-20 Creating Arbitrarily Spaced Frequency-CorrectionPairs in a Swept mm-wave Environment l-40Getting Started Advanced (50 l-42Getting Started Advanced Scalar Analysis Measurement with User Flatness Corrections Figure l-21. Scalar System Configuration 1-44Getting Started Advanced Getting Started Advanced l-45 1-46Getting Started Advanced Using Detector Calibration 1-48Getting Started Advanced Using the Tracking Feature ALC Bandwidth Selection Figure l-23.Decision Tree for ALC Bandwidth Selection l-50Getting Started Advanced Using Step Sweep Creating and Using a Frequency List 1-52Getting Started Advanced Using the Security Features Getting Started Advanced l-53 Changing the Preset Parameters 1-54Getting Started Advanced Getting Started Programming Programming Getting Started Programming l-55 Page Page Page Page Page Page Page Getting Started with SCPI Definitions of Terms query Standard Notation Command Mnemonics Angle Brackets How to Use Examples Command Examples Response Examples Essentials for Beginners Program and Response Messages Forgiving Listening and Precise Talking 1-66Getting Started Programming Page Figure l-25.A Simplified Command Tree Paths Through the Command Tree l-68Getting Started Programming Page Figure l-26.Proper Use of the Colon and Semicolon l-70Getting Started Programming Subsystem Command Tables Figure l-27.Simplified SWEep Command Tree Table 1-2.SWEep Command Table Reading the Command Table More About Commands Query and Event Commands Implied Commands Optional Parameters Program Message Examples Parameter Types Numeric Parameters Page Reading Instrument Errors Example Programs Example Program Description 500mV Figure l-28.Voltage Controlled Oscillator Test Program Listing l-78Getting Started Programming Program Comments l-78 Getting Started Programming Details of Commands and Responses In This Subsection Program Message Syntax Subsystem Command Syntax Figure l-30.Simplified Subsystem Command Syntax Common Command Syntax l-80Getting Started Programming Figure 1-31.Simplified Common Command Syntax Response Message Syntax Figure l-32.Simplified Response MeSSaQe Syntax Getting Started Programming l-81 SCPI Data Types Table 1-3.SCPI Data Types 1-82 Getting Started Programming Page Response Data Types Real Response Data l-84Getting Started Programming Integer Response Data Discrete Response Data String Response Data Getting Started Programming l-85 Programming Typical Measurements Using the Example Programs 1-86Getting Started Programming Use of the Command Tables Table 1-4.Sample Synthesizer Commands Table 1-4.Sample Synthesizer Commands (continued) HP-IBChec Example lrogram 1-88Getting Started Programming Local Lockout Demonstration Example Program Program Comments HINT Setting Up A Typical Sweep, Example l-90Getting Started Programming Page Queries, Example Program 1-92Getting Started Programming Saving and Recalling States, Example Getting Started Programming l-93 l-94Getting Started Programming Looping and Synchronization Using the *WAI Command, Example l-96Getting Started Programming 50: 70: Using the User Flatness Correction Commands 1-96Getting Started Programming Page Page General Status Register Model Transition Filter Event Register Enable Register An Example Sequence l-102Getting Started Programming Figure l-34.Typical Status Register Bit Changes Getting Started Programming l-103 Generalized Trigger Model Figure l-35.Generalized Trigger Model Details of Trigger States Inside the Idle State Getting Started Programming l-105 Figure l-36.Inside the Idle State Inside the Initiate State Figure l-37.Inside the Initiate State l-106Getting Started Programming Inside Event Detection States Getting Started Programming l-107 Page Common Trigger Configurations Figure l-40.The INIT Trigger Configuration The TRIG Configuration l-l10 Getting Started Programming Figure 1-41.The TRIG Trigger Configuration Description of Triggering in the HP 8360 Series Synthesizers Trigger Keyword Definitions Advanced Trigger Configurations l-l12 Getting Started Programming ABORt IMMediate ODELay SOURce Getting Started Programming l-l13 Related Documents The International Institute of Electrical and Electronics Engineers OPERATING AND PROGRAMMING REFERENCE Adrs Menu A-2Operating and Programming Reference Function Group ALC A-4Operating and Programming Reference Page A-6Operating and Programming Reference Page Figure A-2.Typical External Leveling Hookup A-8Operating and Programming Reference Page ALC Bandwidth Select Auto Select High Select Low ALC BW Menu Altmate Rep AM BW Cal Always AM BW Cal Once AM Cal Menu AM Menu AM On/Off 100%/V AM On/Off Ext AM On/Off In-t Amp1 Markers AM Type 10 dB/V AM Type 100%/V (RQS) A-20Operating and Programming Reference Arrow Keys Arrow Keys (EiEi) A-22Operating and Programming Reference Auto Fill Incr Auto Fill #F'ts Auto Fill Start Auto Fill Stop Auto Track Blank Disp (CENTER) See Also (SPAN),(m),(STOP) Center=Narker Clear Fault Clear Memory Clear Point Operating and Programming Reference C-5 CONNECTORS Multi-pin Connectors C-8Operating and Programming Reference Page out I/O TTL J/O TTL out TTL out T’TL Figure C-2. HP-IBConnector and Cable HP-IBInterface Cables Available Operating and Programming Reference C-9 C-10Operating and Programming Reference Figure C-3.Interface Signals of the Source Module Connector Operating and Programming Reference C-l1 RF Output Connector C-12Operating and Programming Reference CorPair Disable 0, Fltness Menu Menu Coupling Factor See Also AALC CW/CF Coupled ($iEqICW) Programming Codes SCPI: NONE Function Group MODULATION D-2Operating and Programming Reference Delete All Menu Menu Map 2,5 All Delete Undef D-4Operating and Programming Reference Page Menu Map k D-6Operating and Programming Reference Disp Status Pls=Off Lvl=Int RF Slp=Off AM=Off Table D-l Mnemonics used to Indicate Status (continued) D-8Operating and Programming Reference Doubler Amp Mode Off See Also Dblr hp Menu See Also Dblr hnp Menu Dblr hnp Dblr f&mp Menu Function Group FREQUENCY Step Sup Menu D-10Operating and Programming Reference HP-IB Enter Corr Programming Codes SCPI: NONE, see Fitness Menu See Also Fltneas Menu Programming Codes SCPI:NONE, see Fltness Menu see Fltness Menu SCPI: NONE,see List Menu Programming Codes SCPI: NONE, see List Menu See Also List Menu ENTRY KEYS Page Function Group SERVICE Fault Info Clear Fault F-2Operating and Programming Reference Programming Codes SCPI:See Fault Menu Fault Menu See Also Fault Menu F-4Operating and Programming Reference Fltness lbnu Auto Fill Incr Auto Fill %Pts Auto Fill Start Auto Fill Stop Figure F-l.Basic User Flatness Configuration Using an HP 4378 Power Meter F-6Operating and Programming Reference Page Figure F-3.The Sources of ALC Calibration Correction Data Figure F-4 Array Configuration when the Correction Data Frequency Span is a Subset of the Synthesizer Frequency Span Operating and Programming Reference F-9 F-10Operating and Programming Reference IALC) F-12Operating and Programming Reference FM an/Off FM adaff lOOk& F-14Operating and Programming Reference an/Off Function Group IhnoD] F-16Operating and Programming Reference FREQUENCY M E N U FREQUENCY (MENU) Freq Offset Step Swp Menu Up/Down Size CW Up/Down Size Swept FREQUENCY (MENU),Freq Offset See Also AM BW Cal Always, AM BW Cal Once, Auto Track Peak RF Always, Peak RF Once, Swp Span Cal Always Swp Span Cal Once F-20Operating and Programming Reference Enter List Dwell, List Menu SCPI:NONE, see List Menu Enter List Offset, List Menu HP-IBAddress Adrs Menu Page Page l-2Operating and Programming Reference Page l-4Operating and Programming Reference Page l-8Operating and Programming Reference Page Function Group IhnoD) Pulse Width Internal Pulse Generator Rate Internal Pulse Genexator Period Trigger See Also 0 Function Group INIOD) Function Group IMOD) Function Group IlvloD] I-10Operating and Programming Reference Function Group (MOq) l-12Operating and Programming Reference See Also (ALC_), 0,MOD Pulse On/Off External, Set Atten Page (ALC) L-4Operating and Programming Reference LINE SWITCH Auto Fill lncr Enter Power Global Duel1 Global Offset Pt Trig Menu Page See Also List Menu, Pt Trig Menu, Sweep Mode List List Menu, Pt Trig Menu, Sweep Mode List Menu, 9t Marker Ml, Start=Ml Stop=MZ Function Group SWEEP kimaL Suesp Power Sweep, Sweep'Mode List M-2Operating and Programming Reference Function Group MENU SELECT Amp1 Markers Center=Marker Delta Mkr Ref Ml--M2Sweep M-4Operating and Programming Reference Page Also M-8Operating and Programming Reference Programming Codes SCPI: MARKer:AOFF Page Page Programming Codes SCPI: MEASure:FM M-10Operating and Programming Reference Page General Circuit Theory M-12Operating and Programming Reference Figure M-l.ALC Block Diagram Amplitude Modulation M-14Operating and Programming Reference Amplitude Modulation Operating and Programming Reference M-15 Figure M-2.Power Accuracy Over the AM Dynamic Range M-16Operating and Programming Reference FM Modulation FM Modulation Operating and Programming Reference M-17 Figure M-3.FM Deviation and Rate Limits M-18Operating and Programming Reference Pulse Modulation Pulse Modulation Page Page Figure M-8.Video Feedthrough M-22Operating and Programming Reference Module Menu Function Group (ALC) Module Select Front M-24Operating and Programming Reference Page Monitor Menu M-28Operating and Programming Reference more n/m Mtr Meas Menu Peak RF Always Peak RF Once P-2Operating and Programming Reference Page P-4Operating and Programming Reference POWER (iZiG) Power Offset Power Slope P-6Operating and Programming Reference Power Sweep P-8Operating and Programming Reference Preset Mode Factory Preset Mode User Printer Adrs P-10Operating and Programming Reference Figure P-l.How [PRIOR)Works Programming Language CIIL P-12Operating and Programming Reference Page Pt Trig Penn Pulse Delay Normal P-14Operating and Programming Reference IhnoD_1 Menu Page Pulse h/Off Extrnl LMOD) Pulse On/Off Intrnl Scalar (MOD) Pulse Period Pulse Rate P-20Operating and Programming Reference Pulse Rise Time klto Pulse Rise Time Fast Pulse Rise Time SlQW Pulse Width (MOD) P-22Operating and Programming Reference Pwr Mtr Range Function Group IALC) Ref Osc Menu Freq ROTARY KNOB R-2Operating and Programming Reference Programming Codes SCPI: *SAV <num Save Lock Save User Preset S-2Operating and Programming Reference SCPI Conformance Information SCPI Conformance Information Operating and Programming Reference S-3 S-4Operating and Programming Reference Operating and Programming Reference S-5 S-6Operating and Programming Reference Operating and Programming Reference S-7 S-8Operating and Programming Reference Operating and Programming Reference S-9 S-10Operating and Programming Reference S-12Operating and Programming Reference Page SCPI COMMAND SUMMARY Introduction IEEE 488.2 Common Commands S-14Operating and Programming Reference Page S-16Operating and Programming Reference Operating and Programming Reference S-17 S-18Operating and Programming Reference SCPI COMMAND SUMMARY Table S-l.HP 8360 SCPI COMMAND SUMMARY Operating and Programming Reference S-19 Page Table S-l.HP 8360 SCPI COMMAND SUMMARY (continued) Operating and Programming Reference S-21 S-22Operating and Programming Reference Table S-l.HP 8360 SCPl COMMAND SUMMARY (continued) Operating and Programming Reference S-23 S-24Operating and Programming Reference Operating and Programming Reference S-25 S-26Operating and Programming Reference Operating and Programming Reference S-27 S-28Operating and Programming Reference Operating and Programming Reference S-29 S-30Operating and Programming Reference Operating and Programming Reference S-31 S-32Operating and Programming Reference Page S-34Operating and Programming Reference Frequency Subsystem S-36Operating and Programming Reference Page Page Operating and Programming Reference S-39 S-40Operating and Programming Reference Page Power Subsystem S-42Operating and Programming Reference Operating and Programming Reference S-43 S-44Operating and Programming Reference Operating and Programming Reference S-45 S-46Operating and Programming Reference Pulse Subsystem S-48Operating and Programming Reference Sweep Subsystem Operating and Programming Reference S-49 Combining the Sweep Mode With the Sweep Generation Command to Obtain the Desired Sweep Condition S-50Operating and Programming Reference Operating and Programming Reference S-51 S-52Operating and Programming Reference Page Page Operating and Programming Reference S-55 SCPI STATUS STRUCTURE S-56Operating and Programming Reference SCPI STATUS REGISTER STRUCTURE Operating and Programming Reference S-57 Security Menu Set Atten Software Rev S-60Operating and Programming Reference (SPAN) Page Start Sweep Trigger Auto See Also (CONT), (-1, Sweep Menu Trigger Bus Trigger Ext Step Control Master S-64Operating and Programming Reference Page Step Control Slave S-66Operating and Programming Reference Step Dwell Step Point3 Step Size Step Swp Menu Mode Trig Auto Trig Bus Menu S-70Operating and Programming Reference Step Swp Pt Trig Ext SWEEP @ii-) S-72Operating and Programming Reference Sweep Mode List Sweep Mode Ramp See Also Swp Span Cal Always See Also Freq Cal Menu Once (SWEEP] See Also (-1 SYSTEM [iii) Operating and Programming Reference S-77 SYSTEM [MENU) 10 MHz Freq Std Auto 10 MHz Freq Std Extml See Also Ref Osc Menu 10 MHz Freq Std 10MHz Freq Std None See Also Ref #SC Menu T-2Operating and Programming Reference Tracking Menu TrigOut Delay Page Uncoupl Atten Unlock Info Up/Down Power CW Up/b Size CV U-2Operating and Programming Reference Up/Dn Size Swept USER DEFINED (Giij U-4Operating and Programming Reference UsrKey Clear UsrMenu Clear U-6Operating and Programming Reference Zero Freq Waveform Menu Function Group LMOD) Zoom See Also (m,(SPAN) Z-2 Operating and Programming Reference ERROR MESSAGES 2a-2Error Messages Error Messages 2a-3 2a-4 Error Messages Synthesizer Specific SCPI Error Messages Universal SCPI Error Messages Error Messages From -499To Error Messages From -399To Error Messages From -299To 2a-6Error Messages Error Messages From - 199 to Error Messages 2a-7 2a-8Error Messages Menu Maps Page Page Page Page Page Page Page Page Page Specifications Frequency Range Resolution Frequency Bands (for CW signals) Frequency Modes: Internal 10 MHz Time Base RF Output Output Power (GHz) Accuracy (dB)4 Frequency (GHz) > 2.0 and 5 Flatness (dB) and Analog Power Sweep External Leveling Source Match Spectral Purity Spurious Signals Page Single-Sideband Phase Noise (dBc/Hz) Offset from Carrier Residual FM (RMS, 50 Hz to 15 kHz bandwidth) Standard Rise/Fall Times Minimum Repetition Frequency Overshoot, Ringing AM and Scan Simultaneous Modulations 2c-12 Internal Modulation Generator Option AM, FM Modulation Meter General Environmental Warm-UpTime Power Requirements Weight & Dimensions Inputs & Outputs Auxiliary Output RF Output External ALC input Pulse input/Output 10 MHz Reference Input 10 MHz Reference Output Sweep Output Stop Sweep Input/Output Z-AxisBlanking/Markers Output Pulse Sync Out (Option 002 only) AM/FM Output (Option 002 only) Models Options Option 001 Add Step Attenuator Page INSTALLATION Options Available 3-2INSTALLATION Line Voltage and Fuse Selection Power Cable 3-4INSTALLATION Figure 3-1.AC Power Cables Available Language Selection Remember How to View or Change a Language Selection from the Front Panel Table 3-1.Language HP-IBAddresses 3-6INSTALLATION HP-IBAddress Selection Figure 3-2.Rear Panel HP-IBSwitch Table 3-2. Factory-Set HP-IBAddresses Mating Connectors 10 MHz Frequency Reference Selection and Warmup Time How to View or Change an HP-IBaddress from the Front Panel Operating Environment Rack Mount Slide Kit (Option 806) Page Figure 3-4.Chassis Slide Kit 3-12INSTALLATION Rack Flange Kit for Synthesizers with Handles Removed Figure 3-5.Rack Mount Flanges for Synthesizers with Handles Removed 3-14INSTALLATION Rack Flange Kit for Synthesizers with Handles Attached (Option 913) Rack Flange Kit for Synthesizers with Handles Attached Figure 3-6.Rack Mount Flanges for Synthesizers with Handles Attached 3-16INSTALLATION Storage and Shipment Environment Package the Synthesizer for Shipment 3-18INSTALLATION Converting HP 6340141 Systems to HP 8360 Series Systems Manual Operation Compatibility Front Panel Operation Instrument Preset Conditions Instrument Preset Conditions for the HP 6360/8340/8341 System Connections The HP 8510 Network Analyzer The HP 8757C/E Scalar Network Analyzer The HP 83550 Series Millimeter-waveSource Modules The HP 89708 Noise Figure Meter 3-22INSTALLATION Remote Operation Language Compatibility Converting from Network Analyzer Language to SCPI Network Analyzer Language Test and Measurement System Language Numeric Suffixes Table 3-7.Numeric Suffixes sllsx Status Bytes 3-24INSTALLATION Table 3-8.Programming Language Comparison Table 3-8.Programming Language Comparison (continued) 3-28INSTALLATION Page Page Page OPERATOR’S CHECK and ROUTINE MAINTENANCE Local Operator’s Check Preliminary Check 4-2Operator’s Check/Routine Maintenance Main Check 1. Press [SERVICE) How to Replace the Line Fuse How to Clean the Fan Filter Figure 4-2.Removing the Fan Filter How to Clean the Cabinet How to Clean the Display Filter Instrument History Page Change B Change B Page Delay12 Compression Internal Pulse Generator Bandwidth Modulation Depth Sensitivity Incidental Phase Modulation Change A Change A S-7 Page IO MHz to 26.5 GHz Range Band Change A 5-10Change A Typical Change A S-11 5-12Change A siguals Ty&al HP K5623A Harmonics s2OGHz outputkeq <4OGHz OWliequencies 1WHr Minimum Repeaiaion FteqUenCY 1nbwnally s50Gi-k Ix~ternal Pulse Generator 5-16Change A Page A M , FM ~V~~OIYIIS: sine. square, triangle, ramp, noise Rate 5-18Change A Page ExmJa.lALcIllput VoWGHz Output S-20Change A AuxmryJJltelface OptiOIlS permitting acmss to Page Index Index-2 Index-3 Index-4 Index-5 Index-6 Index-7 Page Index-9 Index-10 Index Index-12 Index-13 K key Index-14 Index-15 Index-16 Index-17 Page Index-19 Index-20 Index-21 Index-22 Index-23 Index-24 Index-25 Index-26 Index-27