User's Manual
Table Of Contents
- Table of Contents
- List of Figures
- List of Tables
- 1 Introduction
- 2 Installation
- 3 Navigating the LCD Display Screens
- 3.1 Basic Operating Procedure
- 3.2 Starting Point: The Main LCD Touch Screen
- 3.3 LCD Display Flow Chart
- 3.4 Details of the Exciter Status Screens
- 3.4.1 System Status Screen
- 3.4.2 Transport Stream Status Screen
- 3.4.3 Adaptive Processing Board Status Screen
- 3.4.4 Digital Processing Screens
- 3.4.4.1 Modulator Board Status, Screen 1/2
- 3.4.4.2 ADC and DAC Boards Status, Screen 2/2
- 3.4.4.3 FLO FPGA Status, Summary, Screen 1/5
- 3.4.4.4 FLO FPGA, GPS & Clock Status, Screen 2/5
- 3.4.4.5 FLO FPGA, Transport Stream Status, Screen 3/5
- 3.4.4.6 FLO FPGA, SFN FIFO Status, Screen 4/5
- 3.4.4.7 FLO FPGA, MTI Status, Screen 5/5
- 3.4.5 IF & RF Processing Status Screens
- 3.4.6 System Control Status Screens
- 3.5 Built In Tests
- 3.6 Details of the System Setup Screens
- 3.7 RTAC Operating Procedures, Main Screen.
- 4 Theory of Operation
- 5 Maintenance and Troubleshooting
- 5.1 Exciter Maintenance
- 5.2 Loading Software
- 5.3 Default Settings For DIagnostics Screens
- 5.4 Typical Settings for the More Critical Exciter Setups
- 5.5 Exciter Troubleshooting Flow Charts
- 5.6 General Troubleshooting
- 5.7 System Troubleshooting
- 5.8 Exciter Troubleshooting
- 6 Parts List
- Appendix A Exciter GUI Screen Captures
APEX™ Exciter Incorporating FLO™ Technology
Theory of Operation APEX Exciter Analog Assembly Overview
Page: 4-12 888-2604-001 03/08/07
WARNING: Disconnect primary power prior to servicing.
4.4.3.3 Main Phase Lock Loop (Second LO)
Refer to Figure 4-9, Second LO Block Diagram.
The second LO covers 197-663 MHz. It is referenced to the 10 MHz reference oscillator,
which is locked to GPS. It is used to convert the 140 MHz (center channel) second IF to the
desired channel center frequency.
The second local oscillator PLL generates a CW signal which is 140 MHz above the
desired center channel frequency for VHF channels and 140 MHZ below the desired center
channel frequency for UHF channels. Refer to Table 4-2 for a list of frequencies for
channels used within the USA.
A single loop PLL, locked to the 10 MHZ reference oscillator is used to set the 865 MHz
to 1180 MHz VCO to a specific frequency within its frequency range. This chosen
frequency is applied to a divide by N circuit, where N is chosen so that its output, or a
harmonic of its output, falls on the desired second LO frequency. A tunable bandpass filter
is controlled via the micro controller to select the desired frequency and assure that the LO
output is clean.
Figure 4-9 Block Diagram Main Phase Lock Loop (2nd LO)
Table 4-2 2nd LO Output Frequencies
Channel Frequency Range 2nd LO Frequency Channel Frequency Range 2nd LO Frequency
Standard channels for USA FLO RF channel 1 through 8 for USA
2 54 - 60 MHz 197 MHz 1 698 - 704 MHz 561 MHz
4 MHz gap between channels 4 and 5. 2 704 - 710 MHz 567 MHz
6 82 - 88 MHz 225 MHz 3 710 - 716 MHz 573 MHz
7 174 - 180 MHz 317 MHz 4 716 - 722 MHz 579 MHz
13 210 - 216 MHz 353 MHz 5 722 - 728 MHz 585 MHz
14 470 - 476 MHz 333 MHz 6 728 - 734 MHz 591 MHz
69 800 - 806 MHz 663 MHz 7 734 - 740 MHz 597 MHz
8 740 - 746 MHz 603 MHz
2nd LO Output to Up
Converter, +10 dBm
2nd LO Output to Down
Converter, +10 dBm
10 MHz
Reference
Input
2-Way
Splitter
Low Pass
Filter
U36
865 - 1180
U45, Phase
÷ M
MHz VCO
U47
Tunable
Band Pass
Filters
Locked Loop
÷ N