Changing NE IBOC Service Mode

Transcription

1 Changing NE IBOC Service Mode IS06001 Issue March 2006 Nautel Limited Peggy's Cove Road, Hackett's Cove, NS, Canada B3Z 3J4 T F U.S. customers please contact: Nautel Maine, Inc. 201 Target Industrial Circle, Bangor ME T F Copyright 2006 NAUTEL. All rights reserved.

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3 IS06001 Changing NE IBOC Service Mode INFORMATION SHEET 1 INTRODUCTION This document describes how to change the service mode on an NE IBOC exciter. Use this procedure whenever you change the service mode to ensure stable system operation. 2 SERVICE MODE OVERVIEW There are two sets of primary service modes; one set (MP1 to MP4) is for use with hybrid IBOC systems. The second set (MP5 to MP7) is for use with all-digital IBOC systems. An all-digital system also includes a set of secondary service modes (MS1 to MS4). NOTE This document covers service modes MP1 to MP3 only. At time of print, the remaining modes (MP4 and all-digital modes MP5 to MP7 and MS1 to MS4) were not approved for broadcast and are not covered in this document. Service modes vary by the number of IBOC carriers and logical channel allocation of the data on the IBOC carriers. For example, MP2 uses more IBOC carriers than MP1 and therefore has more overall data capacity. Table 1 illustrates the differences between MP1, MP2 and MP3. Changing an IBOC system from one service mode to another has some important ramifications to the transmitter system. First, increasing the number of IBOC carriers increases the required power from the transmitter if the ratio of IBOC carrier power to analog carrier power ( -20dB) is to be maintained. In a low level combined system, adding IBOC carriers results in an overall power change of about 1% (see Table 2). In a high level combined system, adding IBOC carriers may require up to a 20% increase in the transmitter RF power (see Table 3). Table 1: Service Mode Summary Service Mode # of IBOC Carriers IBOC Carrier BW, 1 sideband (Hz) Frequency Offset 1 (Hz) Total Data Capacity 2 (kb/s) Logical Channels (data capacity) MP ,041 ± 129, P1 (98.4) MP ,581 ± 122, P1(98.4), P3(12.4) MP ,485 ± 115, P1(98.4), P3(24.8) 1 Offset of the first IBOC carrier from the centre of the channel 2 Usable data capacity is less due to overhead Table 2: Low Level Combined IBOC System Service Mode Relative RF Power (db) Relative RF Power (%) FM MP1+FM MP2+FM MP3+FM Table 3: High Level Combined IBOC System (IBOC transmitter only) Service Mode Relative RF Power (db) Relative RF Power (%) MP MP MP NE IBOC Service Mode Conversion Guide Page 1 of 6 IS06001 Issue 1.1

4 For Nautel IBOC system using an NE IBOC exciter, there are several adjustments required if the service mode changes: In high level combined systems: IBOC Transmitter RF power set point I/Q Scale Factor. System Configuration: Service Mode In low level combined systems: System Configuration: Service Mode Table 4 lists the maximum RF power for Nautel transmitters used in a high level combined system as the IBOC transmitter. Table 4: RF Power Limits: IBOC only Transmitter Maximum Digital Power (W) FM1 250 FM2 500 V V EQUIPMENT REQUIRED Spectrum analyzer RF power meter 4 CHANGING SERVICE MODE (a) Save your default NE IBOC configuration (if not, the configuration will be reset when you change the service mode): Enter the NE IBOC s SYSTEM> Command menu (see Figure 1). Select the Display Results check box and enter makedef in the command field (see Figure 2). Press the Execute button. The screen in Figure 3 will be displayed to indicate that your default configuration has been saved. Figure 1: Entering the SYSTEM>Command Menu Page 2 of 6 Issue 1.1 NE IBOC Service Mode Conversion Guide IS06001

5 Figure 2: System Command Menu Figure 3: Confirmation of saved default configuration NE IBOC Service Mode Conversion Guide Page 3 of 6 IS06001 Issue 1.1

6 (b) For V5 or V10 transmitters with dual exciters, disable automatic exciter changeover (see V10/V5 Installation and Operation manual for details). (c) Unplug the HD-R data cable from the NE IBOC. NOTE For high level combined systems, a loss of HD-R data will result in a service interruption for the IBOC transmitter. Low level combined systems will continue to broadcast the analog signal. (d) If the system does not use an importer, change the service mode using the NE IBOC s GUI: See Figure 4: Enter the SYSTEM>Configuration menu and save your current configuration for possible future use. See Figure 5: Select the desired service mode from blue-green shaded choices. In the Restart Options box, select Load Default Configuration. Press the Restart button. The NE IBOC will restart. (e) If the system uses an importer, use the importer s GUI to select the configuration with the appropriate service mode. Activate the configuration. NOTE Ensure the selected configuration has been modified for correct services and bit rates. Refer to the importer s documentation for details. (f) If the transmitter system is a low level combined system, proceed to step (k). (g) For a high level combined system, determine the new power set point based on Tables 2 and 3. (h) Example: to change from MP1 to MP2, increase the transmitter s power set point by 10% (changing to MP3 requires a further increase of 10%). If the optimum set point for the new service mode is higher than the RF power limit indicated in Table 4, set the RF power set point to the RF power limit. (i) Adjust the I/Q Scale factor. See Figure 6: Enter the SIGNAL>I/Q Scale Factor menu of the NE IBOC. The NE IBOC will display the menu shown in Figure 7. Key in the appropriate I/Q scale factor (see below) and press Enter: Mode I/Q scale factor MP1 400 MP2 381 MP3 365 (j) Adjust the RF output power by the amount determined in step (h). For FM1 or FM2 transmitters, adjust the power through the M50 GUI (see the M50 Installation and Operation manual). For V5 or V10 transmitters, adjust the power through the V5 or V10 GUI (see the V10/V5 Installation and Operation manual) (k) Verify that all necessary changes have been made. You may need to reset station information and re-adjust diversity delay. (l) The IBOC carriers can now be restored. Reconnect the HD-R data cable to the NE IBOC. For V5 or V10 transmitters with dual exciters, reenable automatic exciter changeover, if desired. (m) Check the IBOC transmitter s RF power level (with an RF power meter) and spectrum (with a spectrum analyzer). Page 4 of 6 Issue 1.1 NE IBOC Service Mode Conversion Guide IS06001

7 Figure 4: Entering System Configuration Menu Figure 5: Selecting Service Mode and Restarting NE IBOC Service Mode Conversion Guide Page 5 of 6 IS06001 Issue 1.1

8 Figure 6: Entering I/Q Scale Factor Menu Figure 7: I/Q Scale Factor Menu Page 6 of 6 Issue 1.1 NE IBOC Service Mode Conversion Guide IS06001