Lindos LA100 User manual

LA100 Audio Analyser
Manual
Sixth edition, June 2007
© 2007 Lindos Electronics
Part number: MN100
This manual describes LA100 software version V6.7. Please refer to any accompanying
update sheets if your LA100 displays a version number later than this when it is turned on
or reset. Users familiar with earlier software should refer to appendix I.3 for a list of new
features.
We are continuously developing and enhancing the software within the LA100 and send
major new software EPROMs to all users. You should therefore ensure that you complete
and return the enclosed registration card directly to Lindos Electronics and advise of any
change of ownership or change of address so that you receive these updates.
All comments and suggestions regarding the LA100 will be gratefully received.
LINDOS ELECTRONICS Technical Support (usually 24 hours):
Saddlemakers Lane Telephone: [phone]
Melton
WOODBRIDGE Fax: [phone]
Suffolk IP12 1PP email: [email protected]
ENGLAND

Contents
1.0 Introduction 9
1.1 Viewing Angle 9
1.2 Switching-On 9
1.3 The Keyboard 10
1.4 Reset 10
1.5 Memory Clear and Non-Volatile Memory 11
1.6 The Configuration Menu 12
1.7 Connectors 12
1.8 Technical Support 14
2.0 Manual Operation 15
2.1 Volume Control 15
2.2 Generating Tones 15
2.3 Measuring Tones 16
2.4 Channel Switching 18
2.5 Programmable Presets and Initial Settings 18
2.6 Relative Levels − Test Level (TL) 18
2.7 Measurement Options 19
2.8 Frequency Measurement 21
2.9 Phase Measurement 21
2.10 Noise Measurement 22
2.11 Rumble Measurement 23
2.12 Crosstalk Measurement 23
2.13 Distortion Measurement 24
2.14 Wow and Flutter Measurement 25
2.15 Speed Measurement 26
2.16 Difference Frequency Distortion Measurement 27
2.17 Quantising Distortion (QD) Measurement 29
2.18 Frequency Intermodulation (FIM) Measurement 29
2.19 Standards 30
2.20 400Hz High Pass Filter 30
2.21 Impedance & Impedance Correction (ZC) 30
2.22 dBu, dBV, Volts and Power Measurement 31
2.23 Printing the Displayed Values 33
2.24 Output Waveform 33
2.25 Miscellaneous Features 34
2.26 LA101 Weighting Curves 35
2.27 User Weighting Curves 35
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3.0 Sequence Testing 37
3.1 Running a Sequence 41
3.2 Page Results Mode 42
3.3 Frequency Response Results 43
3.4 Printing Sequence Results 43
3.5 Storing Results in Memory 45
3.6 Cyclic Identification Character 46
3.7 Test Level 46
3.8 Input Level 47
3.9 Choosing a Sequence 47
3.10 Interpreting Sequence Results 50
3.11 Single Channel Operation 50
3.12 Single Register Operation 52
3.13 FSK Failure − Error Codes 53
3.14 Sweep Headroom 53
3.15 Peak Programme Meter (PPM) Testing 55
3.16 Normalisation of Frequency Response 56
3.17 Subtracting Reference Curves 57
3.18 Tests Which Always Subtract a Reference Curve 57
3.19 Oscillator Weightings 57
3.20 Automatic Results Storage 59
3.21 Printout Heading 60
3.22 Printout Date 60
3.23 Running Single Segments 61
3.24 Using Filters for Sequence Measurements 62
3.25 Remote Trigger 62
3.26 Breaking into a Repeating Sequence 63
3.27 CCITT O.33 Compatibility 63
4.0 User Defined Sequences 65
4.1 The Sequence Definition 66
4.2 The LA101 Sequence Editor 68
4.3 Source Identification 69
4.4 Copying a Sequence 71
4.5 Measurement Levels 71
4.6 Test Level Segments (T,V) 72
4.7 Frequency Sweep Segments (OPQRSUXorux) 73
4.8 Noise Segments (L,M,N,n) 73
4.9 Crosstalk Segments (A,B,C,J,c) 74
4.10 Distortion Segments (D,E,F,G,I) 74
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4.11 Wow & Flutter Segment (W) 75
4.12 Phase Segments (Y, Z, z) 75
4.13 User Level Segment (K) 75
4.14 Maximum Output Level (MOL) Segments (H, h) 76
4.15 Difference Frequency Distortion (d) 77
4.16 Tone Burst/Tones Segment (!) 78
4.17 Repeating Segments and Sequences (<) 81
4.18 Multiple Results Compartments 81
4.19 Selecting a Tolerance (±) 83
4.20 Output Impedance Segment (%) 83
4.21 Sequence Level Segment (/) 84
4.22 Channel Segment (:) 84
4.23 Subroutine Segment (>) 85
4.24 Pause Segment (?) 85
4.25 Sweep Headroom (^n) 85
4.26 Subtract a Reference Curve (\n) 86
4.27 Equivalent ! Segments 86
4.28 CCITT O.33 Sequences 87
4.29 Apply weighting (=n) 88
5.0 Tolerance Testing 89
5.1 Applying a Tolerance 92
5.2 Pre-Defined Tolerances 92
5.3 Tolerance Strings 93
5.4 The Tolerance Definition 93
5.5 Printout Format 95
5.5 Printout Format 95
5.6 The LA102 Tolerance Editor 96
5.7 Editing Tolerances on a Remote Computer 98
5.8 Example Tolerance 98
6.0 Using Test Tapes and Discs 101
6.1 Test Tape Mode 101
6.2 Frequency Sweep Mode 103
6.3 Frequency Response Results 104
6.4 Automatic W&F Measurement on Test Tapes 104
7.0 Applications Advice 107
7.1 Tape Machines 107
7.2 Loudspeakers 108
7.3 Microphones & Low Level Inputs 108
7.4 Lines, Links & Networks 109
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7.5 Mixing Consoles 110
7.6 Filters and Equalisers 110
7.7 Compact Disc Players 111
7.8 Amplifiers 111
7.9 Production Testing 111
7.10 Meter Testing 111
7.11 FM Transmitter Systems 112
8.0 Using Printers 113
8.1 Setting Up the Printer 113
8.2 Printing 114
8.3 Printout Format 115
8.4 Printers and the Configuration Menu 115
8.5 Choosing a Printer 117
8.6 9 Pin Dot Matrix Printers 117
8.7 Epson LQ and Other 24 Pin Printers 118
8.8 Inkjet Printers 118
8.9 Portable Printers 119
8.10 Printer Problems 119
9.0 Remote Control 121
9.1 Connecting the LA100 to a Computer 122
9.2 The RS232 Serial Data Format 123
9.3 Entering Remote Mode 123
9.4 Command Format 125
9. 5 Some Examples 126
9.6 Hints on Writing Programs 127
9.7 Errors 130
9.8 General Purpose Commands 131
9.9 LA101 Output Commands 133
9.10 LA101 Preset Commands 135
9.11 LA101 Frequency Sweeps & Tone Burst Commands 136
9.12 LA101 Weighting Curves 137
9.13 LA102 Measurement Commands 137
9.14 Running a Sequence 141
9.15 Defining a Sequence 143
9.16 Reading Sequence Results 144
9.17 LA102 Heading and Date 150
9.18 Tolerance Testing 150
9.19 Memory Operations 151
9.20 Using the Smart Sequence Modes 152
9.21 User Sweeps 153
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9.22 Using Sequences 155
10.0 Service Information 157
10.1 EPROM Replacement 157
10.2 Recalibration 158
10.3 Power Supply Voltage 159
10.4 System Overview 159
10.5 Fault Diagnosis 160
10.6 Selftest Failed 161
10.7 5V Power Supply Check 161
10.8 ±15V Power Supply Check 162
10.9 Battery Testing 162
10.10 No LA101 Output 164
10.11 Level Errors 164
10.12 Reed Relay Faults 165
10.13 Microprocessor Faults 166
10.14 Display Faults 167
10.15 Replacing Boards 167
10.16 Spares 167
10.17 LA101 Loudspeaker 168
Appendix A Accessories 169
A.1 Items Supplied with the LA100 169
A.2 Computer Support Software 169
A.3 Conversion Kits (Rack Mount/Separate) 169
Appendix B Audio Sockets 171
B.1 Rear XLR Connectors 171
B.2 Front Jack Sockets 172
B.3 BNC Sockets 172
Appendix C RS232 Connections 173
Appendix D Circuit Diagrams 175
Appendix E Error Messages 179
Appendix F Frequency Lists 182
F.1 IEC Third Octave Frequencies (and remote codes) 182
F.2 LA101 Frequencies and Remote Codes 182
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Appendix G LA102 Filter Graphs 185
Appendix H FSK Header Format 187
Appendix I LA100 Versions 188
I.1 LA100 History 188
I.2 Upgrading Early Units 188
I.3 Software Changes 188
I.4 Rack Mounted Unit (LA100R) 192
I.5 CCITT O.41 Filter Version (LA100C) 192
I.6 Power Supply Monitoring (LA100P) 193
I.7 Telecom Australia Version (LA100T) 193
Appendix J Specification 194
J.1 LA101 Audio Oscillator 194
J.2 LA102 Audio Measuring Set 195
J.3 Common to Both Units 197
Index 199
List of Tables
1.5 Configuration Options 13
2.6 Measurement Options 20
2.19 Impedance Correction Modes 31
3.1 Default sequences 38
3.2 Test Segments 40
3.14 Allocation of Sequence Banks 47
4.1 Control segments 67
5.3 Pre-defined Tolerances in the LA102 90
8.1 Printer configurations 117
9.3 Remote Command Summary 130
F.1 Third Octave Frequencies and Remote Codes 184
F.2 LA101 Frequencies and Remote Codes 186
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8

1.0 Introduction
The first time user should read this chapter, which describes basic features common to
both units, but may then proceed to chapters 2 or 3 for a complete introduction to either
manual or sequence measurement. Sequence measurement is a very easy way of making
a predefined sequence of measurements, at the press of a few keys, without any
programming effort, and without any connection between units other than the signal path.
New users should refer to chapter 7 for applications advice on testing specific devices and
also appendix A which lists the items supplied with the LA100 and the optional
accessories which are available. Other sections of the manual give further information on
defining sequences, tolerance testing, using printers, remote computer control via the
serial (RS232) interface and on servicing the LA100 as there is no separate service
manual. In all cases the most important information can be found at the start of each
chapter; the sections towards the end of each chapter describe the technical details and
more specialist applications.
Although the LA101 Audio Oscillator and LA102 Audio Measuring Set are two
independent units, they are generally used together, and for convenience are then referred
to as the LA100 Audio Analyser. The LA100R is a rack mount version of the LA100
consisting of the LA101 and LA102 bolted together, side by side, to go into a 19" rack.
See appendix A for conversion kit details. Conversion kits 19" rack mounting
1.1 Viewing AngleLCD contrast Lighting the display Backlit display
The full-graphic liquid crystal display in these units combines great flexibility of display
with very low power consumption. Units with serial numbers below 3430 use non-backlit
displays, and for good contrast it is essential that light strikes the display from above the
normal and is reflected off towards the eye below the normal. This requires a large angle
of tilt, or high mounting on a shelf or in a rack. Later units are fitted with high contrast
backlit displays, and the viewing angle is less critical. Earlier units can be upgraded to
the backlit display. A contrast adjustment is fitted inside the top cover (section 10.14)
which gives some optimisation for different viewing angles, but the units are supplied set
for best overall results.
1.2 Switching-OnSwitching on Mains voltage Power supply Mains power supply Power supply voltage
The units can be powered either from the mains or from their internal rechargeable
batteries. The button controls the battery power and the units will always be on
when the mains is connected. There is no mains switch as power consumption is
negligible and continuous operation will do no harm. Units are normally supplied for
either 110-120V or 220-240V, 50/60Hz operation and marked accordingly on the back
9

panel; but they can be altered internally by a competent technician (see section 10.3).
For battery operation, press to turn the battery power on. To turn it off press
and hold it briefly. To conserve battery life the unit will switch off
automatically five minutes after the last key press unless it is put into battery lock by
pressing (ie hold and press ). A ‘B’ in the corner of the display
indicates battery operation, and a heavy ‘B’ indicates the battery lock condition. A
flashing ‘B’ indicates that the battery is nearing discharge, and the automatic switch-off
period then shortens to 30 seconds. Low battery Recharge time battery life
The units will operate for around 4-5 hours on a fully charged battery. The battery is
trickle-charged whenever the mains is connected and will take 36 hours to fully recharge.
(Pressing when the mains is connected will divert current from battery charging
to the backlight. The battery will not charge but the light will be brighter.
To achieve optimum power management in the unit, the backlight will operate for about
an hour from a fully charged battery. The unit will continue without backlight for about
3-4 hours.
When operating from a mains supply the backlight will be at reduced intensity for about
30 minutes after switch on if the battery is in a heavily discharged condition. Backlight
1.3 The Keyboard
In the interest of simple error free operation, the units have only a small number of keys,
each clearly labelled underneath with its main function. The deceptively simple keyboard
hides the vast range of functions which are obtained by pressing combinations of keys, as
described in this manual and in the Quick Reference Card, but they need not concern the
beginner or occasional user.
The key is like a computer’s shift key: while pressed it gives other keys a second
function (it does nothing by itself). In this manual a in front of another key indicates a
second function requiring the key to be held while the key is pressed. In particular,
to generate the numbers 6-10. Most keys repeat if held for a short while.
1.4 ResetNon-volatile memory
When turned on, or after a reset, the state of both units is determined by their
configuration settings stored in non-volatile memory. As supplied, or following removal
of the battery, configurations are set to the Lindos default settings, but these can be
changed using the configuration menu described below. In default configuration the
LA101 generates 0dBu (0.775V) at 1kHz and the LA102 goes into its flat level-
measurement mode. Tapping briefly at any time causes a reset, momentarily
displaying the unit’s serial number and software version (Fig 1.1) and providing a fresh
10
1. Introduction