Audio Precision ATS-1 User manual

ATS-1 Audio Test System - Access
User’s Manual
Advanced Test Equipment Rentals
www.atecorp.com 800-404-ATEC (2832)
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ATS-1 Access
User’s Manual
Firmware Version 3.10
October 1998
Audio Precision Part No. 8211.0043

Copyright © 1998 Audio Precision, Inc. All rights reserved. No part of this
document may be reproduced or transmitted in any form or by any means,
electronic or mechanical, including photocopying, recording, or by any information
storage and retrieval system, without permission in writing from the publisher.
Audio Precision®, System One®, System One + DSP, System Two,
FASTTEST®, APWIN, Portable One®, Accessand Dual Domain® are
trademarks or registered trademarks of Audio Precision, Inc.
This mark signifies that the product conforms to all applicable
requirements of the European Community. A Declaration of
Conformance is included with the user information that describes the
specifications used to demonstrate conformity.
Published by:
Printed in the United States of America
Audio Precision, Inc.
PO Box 2209
Beaverton, Oregon 97075-2209
U.S. Toll Free: 1-800-231-7350
Tel: [phone] Fax: [phone]
email: [email protected]
Web: www.audioprecision.com

CONTENTS
Safety Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii
Safety Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . viii
Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
Scope of this manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
Related documentation ............................. 1-2
Introducing the ATS-1 Access . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
Filter Shapes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6
Identification of Features and Options . . . . . . . . . . . . . . . . . . . . . 1-9
IMD Option . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-9
Connector Panel Options . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-9
Optional Filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-9
Options Label . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-10
Block Diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-11
Overall Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-11
Generator Output Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-13
Analyzer Input Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-15
Getting Started . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
Connecting Mains Supply Voltage . . . . . . . . . . . . . . . . . . . . . . . . 2-1
Rackmounting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
Concepts and Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
Analog vs. Digital . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
Balanced vs. Unbalanced . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3
Self Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
Operational Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
Front Panel Controls and Connectors . . . . . . . . . . . . . . . . . . . . . . 3-1
FUNCTION Keys . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
FREQUENCY Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2
AMPLITUDE Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2
INPUT Keys . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3
OUTPUT Keys . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3
INSTRUMENT MODE Keys . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4
RECALL/SAVE Key . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4
Soft Keys . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4
ATS-1 Access User's Manual iii

LCD Display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4
dBr Zero Key . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5
GPIB Status Indicators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5
CONTRAST Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5
MONITOR Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-6
POWER Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-6
Setup Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-10
Screen Saver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-11
Controlling the Generator . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-12
Generator Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-12
Generator Loading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-14
Controlling the Analyzer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-15
Analyzer Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-15
Input Selection Keys . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-16
FUNCTION Keys . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-16
Units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-17
Is it dBm or dBu? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-20
Power Units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-21
Time and Frequency units . . . . . . . . . . . . . . . . . . . . . . . . . . 3-22
Phase units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-23
Generator Output and Analyzer Input connectors . . . . . . . . . . . . . . 3-24
Rear Panel Connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-25
Trigger Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-25
Monitor Outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-26
Printer Connector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-26
GPIB Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-27
Power Cord Connector and Line Voltage Selector . . . . . . . . . . . . 3-27
External Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-28
Analog Inputs and Outputs . . . . . . . . . . . . . . . . . . . . . . . . . 3-28
Input and Output Cables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-30
BNC Connector Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-30
Unbalanced Connections with the XLR Connector Panel . . . . . . . . . 3-33
Unbalanced Stereo Connections . . . . . . . . . . . . . . . . . . . . . . 3-35
CONTENTS
iv ATS-1 Access User's Manual

FUNCTION Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1
Amplitude . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1
Noise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-4
Level . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-5
THD+N (Total Harmonic Distortion plus Noise) . . . . . . . . . . . . . . . . . 4-7
Understanding THD+N . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-11
Surprises and Pitfalls in THD+N Measurements . . . . . . . . . . . . . . . . 4-13
What Signal is Dominant? . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-13
Selecting Bandwidth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-14
Changes with Frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-17
Changes with Amplitude . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-18
THD+N at 100% (or 0 dB) . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-19
Isolating Sources of THD+N . . . . . . . . . . . . . . . . . . . . . . . . . 4-20
SINAD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-22
Phase . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-25
IMD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-27
Ratio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-29
W+F (Wow and Flutter) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-32
XTALK (Crosstalk) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-34
AC Mains (Power Line Monitor) . . . . . . . . . . . . . . . . . . . . . . . . . . 4-36
Gen Load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-38
Bargraphs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-40
Sweeps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-42
Starting the Sweep . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-45
Continuous Sweeps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-45
External Sweeps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-46
Printing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-46
Saving and Recalling Setups . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-51
Printing Saved Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-53
Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1
Frequency Response of
Amplifiers, Mixing Consoles, Etc. . . . . . . . . . . . . . . . . . . . . . . . . . 5-1
Audio Transmission Link Testing . . . . . . . . . . . . . . . . . . . . . . . . . 5-1
Analog Tape Recorder Alignment and Performance Verification . . . . . . 5-2
Reproduce Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2
Record-Reproduce Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-3
Compact Disc Players . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-5
CONTENTS
ATS-1 Access User's Manual v

Appendix A - Changing Mains Voltage Selection . . . . . . . . . . . . . . A-1
Checking the Selected Line Voltage . . . . . . . . . . . . . . . . . . . . . . . A-1
Changing the Line Voltage Selection . . . . . . . . . . . . . . . . . . . . . . . A-2
Checking the Fuse Block Orientation . . . . . . . . . . . . . . . . . . . . . . . A-3
Changing the Fuse Block Orientation . . . . . . . . . . . . . . . . . . . . . . . A-4
Checking the Fuses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-5
Appendix B - Rackmounting . . . . . . . . . . . . . . . . . . . . . . . . . B-1
Fixed Rack Mount . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-2
Appendix C - Performing Internal Changes . . . . . . . . . . . . . . . . . C-1
Opening the Case . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-1
Changing to Alternate Connector Panels . . . . . . . . . . . . . . . . . . . . C-2
Swapping Speaker and Connector Panels . . . . . . . . . . . . . . . . . . . . C-3
Option Filter Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-6
Monitor Source Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-7
Appendix D - Specifications . . . . . . . . . . . . . . . . . . . . . . . . . D-1
Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Index-1
CONTENTS
vi ATS-1 Access User's Manual

Safety Symbols
The following symbols may be marked on the panels or covers of
equipment or modules, and are used in this manual:
WARNING! - This symbol alerts you to a potentially hazardous
condition, such as the presence of dangerous voltage that could pose a
risk of electrical shock. Refer to the accompanying Warning Label or
Tag, and exercise extreme caution.
ATTENTION! - This symbol alerts you to important operating
considerations or a potential operating condition that could damage
equipment. If you see this marked on equipment, consult the User’s
Manual or Operator’s Manual for precautionary instructions.
FUNCTIONAL EARTH TERMINAL - This symbol marks a terminal
that is electrically connected to a reference point of a measuring circuit
or output and is intended to be earthed for any functional purpose
other than safety.
PROTECTIVE EARTH TERMINAL - This symbol marks a terminal that
is bonded to conductive parts of the instrument. Confirm that this
terminal is connected to an external protective earthing system.
ATS-1 Access User's Manual vii

Safety Information
Do NOT service or repair this product unless properly qualified.
Servicing should be performed only by a qualified technician or an
authorized Audio Precision distributor.
Do NOT defeat the safety ground connection. This product is
designed to operate only from a 50/60 Hz AC power source (250 Vrms
maximum) with an approved three-conductor power cord and safety
grounding. Loss of the protective grounding connection can result in
electrical shock hazard from the accessible conductive surfaces of this
product.
For continued fire hazard protection, fuses should be replaced ONLY
with the exact value and type indicated on the rear panel of the
instrument and discussed on page 7-5 of this manual. The AC voltage
selector also must be set to the same voltage as the nominal power
source voltage (100, 120, 230, or 240 Vrms) with the appropriate
fuses. Different fuses are required depending on the line voltage.
The International Electrotechnical Commission (IEC 1010-1) requires
that measuring circuit terminals used for voltage or current
measurement be marked to indicate their Installation Category. The
Installation Category is defined by IEC 664 and is based on the
amplitude of transient or impulse voltage that can be expected from
the AC power distribution network. This product is classified as
INSTALLATION CATEGORY II, abbreviated “CAT II” on the
instrument front panel.
Do NOT substitute parts or make any modifications without the written
approval of Audio Precision. Doing so may create safety hazards.
This product contains lithium batteries. Dispose only in accordance
with applicable regulations.
This product is for indoor use - pollution degree 2.
viii ATS-1 Access User's Manual

Description
Scope of this manual
This is the primary operator’s manual for the ATS-1 Access. It
describes all aspects of the instrument’s features and functionality. For
fundamental audio test and measurement information, we refer you to
Audio Precision’s Audio Measurement Handbook, listed on the
following page.
This first section is a basic introduction to the physical and electrical
characteristics of the instrument, including options. Some simplified
diagrams and brief discussion help you gain insight into the instrument
performance.
Section 2 provides instruction and overview for connecting and turning
on the instrument, performing a self-test, and gaining insight to the
connectors and front-panel display and controls.
Section 3 provides an operational overview, description of all controls
and connectors, and discussion of the measurement units that may be
displayed. Cable diagrams are also given to aid fabrication of cables
for specialized requirements.
Specific measurement functions are described in Section 4, as well as
printing capabilities and other operational informantion.
Using the ATS-1 Access to perform tests and measurements in specific
applications is described in Section 5. Rather than detailed instrucitons,
this section provides insights for the experienced user.
Appendices A, B, and C contain service information. Most of these
operations can be performed by the average user, but we urge you to
seek assistance if you are not technically qualified to perform them.
This manual does not include test, calibration, or repair information.
Appendix D presents the instrument specifications. These specifications
are believed correct at the time of printing, but are subject to change or
correction, and therefore presented here for reference only. Consult
Audio Precision for the latest information.
&This symbol is
used throughout this
manual to direct you
to more information
on related topics.
1Description
ATS-1 Access User's Manual 1-1

The ATS-1 Access can be operated via an IEEE-488 (GPIB) controller.
Instructions are given in the ATS-1 GPIB Programmer’s Reference
Guide, listed below.
Related documentation
ATS-1 GPIB Programmer’s Reference Guide AP Part No. 8211.0045
Audio Measurement Handbook AP Part No. 8200.AMH1
Introducing the ATS-1 Access
The Audio Precision ATS-1 Access is a comprehensive two-channel
audio test instrument for performing analog measurements. It features
the following measurement functions:
.Level (two channels simultaneously)
.Noise or signal-to-noise ratio (wideband, weighted, or selective)
.THD+N (total harmonic distortion plus noise)
.Interchannel phase
.SMPTE/DIN intermodulation distortion (optional)
.Real-time two-channel amplitude ratio (interchannel balance or
device gain/loss)
.Real-time frequency-selective crosstalk
.Wow and Flutter
.SINAD (ratio of {signal + noise + distortion} to {noise +
distortion})
.Phase shift through a device
.Loading (AC resistance of the input of a device connected to the
generator output)
.AC mains check (voltage, frequency, and distortion of the AC
power line)
The ATS-1 Access can sweep most of these measurements across a
user-specified frequency or amplitude range and display a graph of the
results. The graph top and bottom values may be set by the user, even
after a sweep, with the data dynamically re-scaling. After sweeping, a
1Description
Related documentation Description
1-2 ATS-1 Access User's Manual

cursor may be used to provide numeric readout of any point on the
graph.
Printer support is provided, allowing printout of high-resolution graphs,
fast screen dumps, numerical data from sweeps or self-test, and
printout of bargraph displays.
The ATS-1 Access is capable of generating low-distortion sine and
square waveforms, plus an intermodulation distortion test signal (when
the intermodulation distortion option is installed).
Figure 1-1. ATS-1 Access
&For information
on setting up the
printer, see page
4-46.
1Description
Description Introducing the ATS-1 Access
ATS-1 Access User's Manual 1-3

Measurements may be displayed in a wide variety of units, including
the following:
.volts
.dBm (with a user-specified impedance reference)
.dBu
.dBV
.dBr (dB relative to a stored measured value)
.dBg (dB relative to the present generator output amplitude)
.watts (with a user-specified impedance reference)
.Hz/kHz
.% or dB for relative measurements
The chosen units are remembered for each measurement function, so
when you return to that function the units will be automatically
displayed.
Several band-limiting and noise-weighting filters are provided:
.Standard 22 Hz-22 kHz audio bandpass
.30 kHz and 80 kHz lowpass
.400 Hz highpass
.Tunable 1/3 octave bandpass
.A-weighting (IEC-A)
.CCIR weighting
.Sockets for two optional filters, selectable from a wide variety
The selected filter for each measurement function is remembered, so
that next time you use that function the same filter will be selected.
Signals within the audible range can be monitored using the built-in
loudspeaker or with user-supplied headphones. An external volume
control is provided.
Up to 30 complete panel setups can be stored in internal memory so
that common test setups can be easily recalled. This memory persists
even when the unit is unplugged. In addition, test setups can be stored
&For information
on filter shapes, see
page 1-6.
1Description
Introducing the ATS-1 Access Description
1-4 ATS-1 Access User's Manual

with a set of data, so that field test results can be saved for later
analysis or printing.
All measurements, settings, and graphs are displayed on a sharp, clear,
backlighted liquid crystal display.
The ATS-1 may be operated manually from the front panel, or may be
programmed via the IEEE-488 computer port. This User’s Manual
describes manual operation. See the ATS-1 GPIB Programmer’s
Reference Manual for complete documentation on controlling the
ATS-1 via IEEE-488.
The ATS-1 Access can be purchased with or without the IMD option,
which allows generation and analysis of intermodulation distortion.
The IMD measurement function conforms to the SMPTE and DIN
testing standards, and is described on page 4-27.
The ATS-1 Access may also be purchased with the EGZ option, which
replaces the 150 Ωgenerator output impedance selection with 200 Ω,
which is more common in European broadcast.
Other options include optional filters for specific band-limiting or
weighting applications, a choice of front panel connectors (described
on Page 1-8), and a rackmount kit.
Any installed options are listed on the Options Label on the rear panel.
1Description
Description Introducing the ATS-1 Access
ATS-1 Access User's Manual 1-5

Filter Shapes
This section shows the shapes of the filters built into the ATS-1 Access.
A number of other filter shapes are available as option filters.
-40
+10
-30
-20
-10
+0
d
B
r
10 200k20 50 100 200 500 1k 2k 5k 10k 20k 50k 100k
Hz
Figure 1-2. Shapes of Bandwidth-limiting filters:
22 Hz Highpass,
400 Hz Highpass,
22 kHz Lowpass,
30 kHz Lowpass,
80 kHz Lowpass
1Description
Filter Shapes Description
1-6 ATS-1 Access User's Manual

CCIR-468-4
DOLBY
Figure 1-3. Shape of CCIR filter. CCIR-468-4 has the 0 dB point at 1 kHz, while the
Dolby curve has the 0 dB point at 2 kHz.
Figure 1-4. Shape of A-weighting filter
1Description
Description Filter Shapes
ATS-1 Access User's Manual 1-7

Identification of Features and Options
IMD Option
The IMD (Intermodulation Distortion) measurement function is
available only if the IMD option has been installed. If present, this
option will be marked on the Options label on the rear panel (see page
1-9). If not present, the front-panel IMD button will have no effect.
Connector Panel Options
The connector panel normally shipped with the ATS-1 Access has
BNC connectors and banana jacks for the generator outputs and
analyzer inputs and is mounted on the front. This is the configuration
shown in the figures in this manual. Alternatively, the connector panel
may be mounted on the rear, and the speaker panel mounted on the
front.
Other connector panel options are available, and may be ordered with
the instrument or installed later by the user. Connector panel options
are: .3-pin XLR and banana jack connectors
.WE-310 tip-ring-sleeve and banana jack connectors
.1/4-inch phone and banana jack connectors
To install connector panel options or to swap the connector and
speaker panels, refer to Appendix C.
Optional Filters
In addition to the built-in filters, the ATS-1 provides two positions for
optional filters that can be installed in the field. Refer to Appendix C for
cautions and installation procedure.
1Description
Identification of Features and Options Description
1-8 ATS-1 Access User's Manual

Options Label
The Options Label (see Figure 1-5) specifies any options that are
installed in your ATS-1 Access. It is located on the lower center of the
rear panel.
The options label is filled out by the manufacturing technician when
configuring the instrument for the customer. If the IMD or EGZ options
are installed, an X will be placed in the appropriate box.
If option filters are installed, the type of filter will be marked in the
appropriate Optional Filters box.
The date of original manufacture will be written in the appropriate box.
If there are any other unique characteristics of the unit, codes will be
placed in the ‘Special’ box. These may be special modifications or
requirements from certain upgrade combinations.
Date of manufacture FW Version
Audio Measurement System
Aux 2:
Aux 1:
Optional Filters:
Installed Options:
Special
EGZ Euro. Impedances
ATS-IMD Intermod. Distortion
Figure 1-5. Options label
1Description
Description Identification of Features and Options
ATS-1 Access User's Manual 1-9

Block Diagrams
This section contains several diagrams to assist your understanding of
how the ATS-1 Access accomplishes its measurement tasks. While
knowledge of the internal circuitry is not required for operation of the
instrument, it may be more intelligently applied, and its limitations may
be better understood, by referring to these diagrams.
Overall Block Diagram
Figure 1-6 is a simplified block diagram of the ATS-1 Access.
The generator consists of a sinewave and squarewave generator
transformer-coupled to the output connectors. When the IMD option
is present, a second sinewave oscillator is added. Its output is summed
with the main oscillator to provide the necessary two-tone signal. With
the IMD waveform selected, the rear panel Analog Trigger output
carries the lower-frequency tone of the IMD tone pair for oscilloscope
triggering.
The analog analyzer consists of two identical wide-range autoranging
preamplifiers, a principal meter with filters, a secondary meter, a wow
and flutter discriminator, and phase and frequency meters.
The principal meter consists of a switchable and tunable bandpass or
bandreject filter, additional amplification, built-in high-pass and
low-pass filters, built-in CCIR and A-weighting filters, and two sockets
for optional filters. The bandreject is used in THD+N and SINAD
functions. The bandpass filter is used in the SELECTIVE modes of the
AMPLITUDE and NOISE functions and in the XTALK function.
The output of either the principal meter or the wow and flutter
discriminator feeds the primary reading detector. The primary
detector, depending on the measurement function and setup
parameters of that function, may have true RMS, average, or
quasi-peak response. The primary reading is normally displayed in the
upper-left corner of the display on the Main panel or Analyzer Only
panel and graphed with solid lines in sweeps of all functions except
PHASE.
1Description
Block Diagrams Description
1-10 ATS-1 Access User's Manual

MICROPROCESSOR
BAND PASS
BAND REJECT
FILTER
WOW &
FLUTTER
DISCRIMINATOR
MEASUREMENT
AMPLIFIER
WEIGHTING
FILTERS
PHASE/FREQ
COMPARATORS
INTERMOD
DEMODULATOR
INPUT
PREAMP
and
ATTENUATOR
PRIMARY
READING
DETECTOR
SECONDARY
READING
DETECTOR
LCD DISPLAY
INTERMODULATION DISTORTION OPTION
INPUT
TERMINATION
INPUT
TERMINATION
CHANNEL A
CHANNEL B
GENERATOR
OUTPUTS
CHANNEL
A
CHANNEL
B
IMD HF TONE
GENERATOR
SQUARE
WAVE
GENERATOR
MAIN
OSCILLATOR
SIGNAL
SUMMATION
OUTPUT
AMPLIFIER
BALANCING
TRANSFORMER
OUTPUT
ATTENUATOR
SOURCE
IMPEDANCE
SOURCE
IMPEDANCE
BACK
TERMINATION
BACK
TERMINATION
INTERNAL
JUMPER
INPUT
MONITOR
SPEAKER/
HEADPHONE
READING
MONITOR
ANALOG
TRIGGER
OUTPUT
Cut Jumper
if IMD Option
Installed
ANALYZER
INPUTS GEN-MON
SWITCHING
Figure 1-6. Overall block diagram of the ATS-1 Access
1Description
Description Block Diagrams
ATS-1 Access User's Manual 1-11