Crown FM600 Manuel utilisateur
FM600 Broadcast Transmitter
User's Manual
©2008 Crown Broadcast, a division of
International Radio and Electronics Corporation
25166 Leer Drive, Elkhart, Indiana, 46514-5425 U.S.A. (574) 262-8900
Revision Control
Revision Print Date
Initial Release March 2007
Important Notices
©2008, Crown Broadcast, a division of International Radio and Electronics Corporation.
Portions of this document were originally copyrighted by Michael P. Axman in 1994.
All rights reserved. No part of this publication may be reproduced, transmitted, transcribed,
stored in a retrieval system, or translated into any language in any form by any means without
the written permission of International Radio and Electronics, Inc.
Printed in U.S.A.
Crown Broadcast attempts to provide information that is accurate, complete, and useful.
Should you find inadequacies in the text, please send your comments to the following address:
International Radio and Electronics Corporation
P.O. Box 2000
Elkhart, Indiana, 46515-2000 U.S.A.
ii
Revision A January 2008
Contents
Section 1– Getting Acquainted 1-1
1.1 Your Transmitter 1-2
1.2 Applications and Options 1-3
1.2.1 Stand Alone 1-4
1.2.2 Backup 1-4
1.2.3 Exciter 1-4
1.2.4 Translator 1-5
1.2.5 Satellator 1-6
1.3 Transmitter/Exciter Specifications 1-7
1.4 Receiver Specifications 1-9
1.5 Safety Considerations 1-9
1.5.1 Dangers 1-9
1.5.2 Warnings 1-9
1.5.3 Cautions 1-9
Section 2– Installation 2-1
2.1 Operating Environment 2-2
2.2 Power Connections 2-2
2.2.1 AC Line Voltage Setting 2-2
2.2.2 Fuses 2-3
2.3 Frequency (Channel) Selection 2-4
2.3.1 Modulation Compensator 2-6
2.4 Receiver Frequency Selection 2-7
2.5 RF Connections 2-11
2.6 Audio Input Connections 2-12
2.7 SCA Input Connections 2-13
2.8 Composite Input Connection 2-13
2.9 Audio Monitor Connections 2-14
2.10 Pre-emphasis Selection 2-14
2.11 Program Input Fault Time-out 2-15
2.12 Remote I/O Connector 2-15
iii
Section 3-Operation 3-1
3.1 Initial Power-up Procedures 3-2
3.2 Power Switches 3-4
3.2.1 Power Switch 3-4
3.2.2 Carrier Switch 3-4
3.3 Front Panel Bar-Dot Displays 3-5
3.3.1 Audio Processor Input 3-5
3.3.2 Highband and Wideband Display 3-5
3.3.3 Modulation Display 3-5
3.4 Input Gain Switches 3-6
3.5 Processing Control 3-6
3.6 Stereo-Mono Switch 3-6
3.7 RF Output Control 3-7
3.8 Digital Multimeter 3-7
3.9 Fault Indicators 3-8
Section 4-Principals of Operation 4-1
4.1 Part Numbering 4-2
4.2 Audio Processor/Stereo Generator Circuit Board 4-3
4.2.1 Audio Processor Section 4-3
4.2.2 Stereo Generator Section 4-4
4.3 RF Exciter Circuit 4-6
4.4 Metering Circuit 4-7
4.5 Motherboard 4-8
4.6 Display Circuit Board 4-10
4.7 Driver Switch logic Board 4-11
4.8 RF Driver 4-13
4.9RFAmplifier 4.14
4.10 Chassis 4-15
4.11 RF Output Filter & Reflectometer 4-15
4.12 Receiver Circuit Board Option 4-16
iv
Section 5-Adjustments and Tests 5-1
5.1 Audio Processor Adjustments 5-2
5.1.1 Pre-Emphasis Selection 5-2
5.1.2 Pre-Emphasis Adjustment 5-2
5.2 Stereo Generator Adjustments 5-2
5.2.1 Separation 5-2
5.2.2 Composite Output 5-3
Using a Modulation Monitor 5-3
5.2.3 19kHz Level 5-3
5.2.4 19kHz Phase 5-3
5.3 Frequency Synthesizer Adjustments 5-3
5.3.1 Frequency (Channel) Selection 5-3
5.3.2 Modulation Compensator 5-4
5.3.3 Frequency Measurement and Adjustment 5-4
5.3.4 FSK Frequency Offset Control 5-4
5.4 Metering Board Adjustments 5-4
5.4.1 Power Calibrate 5-4
5.4.2 Power Set 5-4
5.4.3 SWR Calibrate 5-5
5.4.4 PA Current Limit 5-5
5.5 Motherboard Configuration 5-5
5.6 Display Modulation Calibration 5-5
5.7 Driver Switch Logic Adjustment 5-6
5.8 Bias Set (RF Power Amplifier) 5-6
5.9 Performance Verification 5-7
5.9.1 Audio Proof of Performance Measurements 5-7
5.9.2 De-Emphasis Input Network 5-7
5.10 Carrier Frequency 5-8
5.11 Output Power 5-8
5.12 RF Bandwidth and RF Harmonics 5-8
5.13 Pilot Frequency 5-8
5.14 Audio Frequency Response 5-8
5.15 Audio Distortion 5-9
5.16 Modulation Percentage 5-9
5.17 FM and AM Noise 5-9
5.18 Stereo Separation 5-9
5.19 Crosstalk 5-9
5.19.1 Main Channel Into Sub 5-9
5.19.2 Sub Channel Into Main 5-9
5.20 38kHz Subcarrier Suppression 5-10
5.21 Additional Checks 5-10
v
Section 6-Reference Drawings 6-1
6.1 Views 6-2
6.2 Board Layouts and Schematics 6-4
Section 7-Service and Support 7-1
7.1Service 7-2
7.2 24-Hour Support 7-2
Transmitter Output Efficiency Appendix-1
Glossary G-1
Index Index-1
vi
Section 1—Getting Acquainted
This section provides a general description of the FM600 transmitter and
introduces you to safety conventions used within this document. Review
this material before installing or operating the transmitter.
1-1Getting Acquainted
1.1 Your Transmitter
The FM600 is a member of a family of FM stereo broadcast transmitters. Crown transmitters
are known for their integration, ease-of-use, and reliability.
The integration is most apparent in the standard transmitter configuration which incorporates
audio processing, stereo generation, and RF amplification without compromised signal quality.
A single Crown transmitter can replace several pieces of equipment in a traditional system.
Ease-of-use is apparent in the user-friendly front panel interface and in the installation
procedure. Simply select your operating frequency (using 5 external switches), add an audio
source, attach an antenna, and connect AC power and you're ready to broadcast. Of course,
the FM series of transmitters also feature more sophisticated inputs and monitoring
connections if needed.
Reliability is a Crown tradition. The first Crown transmitters were designed for rigors of
worldwide and potentially portable use. The modular design, quality components, engineering
approach, and high production standards ensure stable performance.
Remote control and metering of the transmitter are made possible through a built-in I/O con-
nector. For more direct monitoring, the front panel includes a digital multimeter display and
status indicators. Automatic control circuitry provides protection for high VSWR as well as high
current, voltage, and temperature conditions.
Illustration 1-1 FM600 Stereo Broadcast Transmitter
1-2 FM600 Manual
1.2 Applications and Options
Crown transmitters are designed for versatility in applications. They have been used as
stand-alone and backup transmitters and in booster, translator, satellator, and nearcast
applications. The following discussion describes these applications further.
Model numbers describe the configuration of the product (which has to do with its intended
purpose) and the RF output power which you can expect.
The number portion of each name represents the maximum RF output power. The FM600,
for example, can generate up to 600 watts of RF output power.
Suffix letters describe the configuration. The FM600T, for example, is the standard or
transmitter configuration. Except where specified, this document describes the transmitter
configuration. In this configuration, the product includes the following components
(functions):
• Audio Processor/Stereo Generator
• RF Exciter
• Metering
• Low-Pass filter
Illustration 1–2 Standard (Transmitter) Configuration
1-3Getting Acquainted
Stereo
Generator
Circuit
Audio
Processor
Circuit
RF Exciter Circuit
Metering
Circuit
RF Low Pass filter
1.2.1 Stand-Alone
In the standard configuration, the FM600 is an ideal stand-alone transmitter. When you add
an audio source (monaural, L/R stereo, or composite signal), an antenna, and AC power,
the transmitter becomes a complete FM stereo broadcast station, capable of serving a
community.
As stand-alone transmitters, Crown units often replace multiple pieces of equipment in a
traditional setup (exciter, audio processor, RF amplifier).
1.2.2 Backup
In the standard configuration, Crown transmitters are also used in backup applications.
Should your primary transmitter become disabled, you can continue to broadcast while
repairs take place. In addition, the FM transmitters can replace disabled portions of your
existing system including the exciter, audio processor, or amplifier. Transfer switches on
each side of the existing and backup transmitters make the change-over possible with
minimal downtime.
1.2.3 Exciter
In addition to the standard configuration, the FM600 is available in optional configurations to
meet a variety of needs.
An "E" suffix, as in the FM600E, for example, represents an exciter-only configuration. In
this configuration, the audio processor and stereo generator boards are replaced with cir-
cuitry to bypass their function. The exciter configurations are the least expensive way to get
Crown quality components into your transmission system.
You might consider the Crown exciter when other portions of your system are performing
satisfactorily and you want to maximize your investment in present equipment.
1-4 FM600 Users Manual
Autres manuels pour FM600
1
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