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Summary of Contents for General Instrument C6M-II
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C6M-II ® Commander 6 Modulator Installation Manual TEST REF OFF video modulation (%) -20dB VIDEO C6M-II VIDEO OFF 87.5 VIDEO B AUX IF PRGM IF audio deviation (kHz) REMOTE...
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General Instrument. General Instrument reserves the right to revise this publication and to make changes in content from time to time without obligation on the part of General Instrument to provide notification of such revision or change.
Section 2 Overview Options ........................C6M-II-MOB Kit ...................... C6-DC ........................C6-RC-II Kit ......................C6M-II-SE Kit ......................Model Conventions ..................... Front Panel Controls and Displays ................Rear Panel Connectors ....................The Menu System ......................Using the Menus ..................... Changing a Menu Item ....................
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Composite Baseband Interfacing ................3-12 CMTS / MVP II / C6M-II Connections ..............3-13 C6R-VCII / CMTS / MVP II / C6M-II Connections ............. 3-14 Section 4 System Block Diagrams Video to IF Modulation System ................... Audio to IF Modulation System ..................
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External composite baseband connection ............ 3-12 Figure 3-10 C6M-II / MVP II / CMTS interfacing ............. 3-13 Figure 3-11 C6R-VCII / CMTS / MVP II / C6M-II connections ......... 3-14 Figure 4-1 Video to IF modulation system ..............Figure 4-2 Audio to IF modulation system ..............
Section 1 Introduction The C6M-II is a state-of-the-art television signal modulator for the most demanding CATV applications. The system is packaged in a space saving 1.75-inch high rack-mounted housing and uses efficient switching power supply regulators to minimize power consumption and heat.
Although these documents provide information that may be of interest to you, they are not necessary to install or operate the C6M-II modulator. Document Conventions Before you begin using the C6M-II, familiarize yourself with the stylistic conventions used in this manual: Denotes silk screening on the equipment, typically representing front and rear-panel SMALL CAPS controls, I/O connections and indicators (LEDs).
Introduction If You Need Help If you need assistance while working with the C6M-II, call the General Instrument Technical Response Center at 1-888-GEN-INST (1-888-436-4678). The Technical Response Center is open from 8:00 a.m. to 9:00 p.m. Eastern Time, Monday through Friday. When the Technical Response Center is closed, emergency service only is available on a call-back basis.
Section 2 Overview The C6M-II is a frequency agile modulator offering an output frequency range from 50 MHz to 1 GHz. All standard, HRC, IRC, and EIA frequencies are available either by keying in the frequency or using the convenient channel maps.
RS-485 type interface using RJ-12 connectors. C6M-II-SE Kit The C6M-II-SE is a stereo encoder option for generating stereo sound. It encodes baseband audio based on BTSC standards, and employs dbx-TV noise reduction circuitry to ensure a quality signal. This option does not have Second Audio Program (SAP). For SAP applications, the CMTS should be used.
Front Panel Controls and Displays The front panel of the C6M-II modulator, which includes an operational display, test ports, a keypad for adjustments, a bar graph and a status display, is illustrated in Figure 2-1. Figure 2-1 C6M-II front panel The following table describes the function of each item on the C6M-II front panel.
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BNC type coaxial connector. The eight-digit alphanumeric LED display shows all functions and controls used to operate the C6M-II. The keypad with four arrow push buttons is used to navigate through the menus. When the desired menu item is reached, the right arrow key is used to access the functions.
Overview Rear Panel Connectors The rear panel of the C6M-II modulator with options installed is illustrated in Figure 2-2. Figure 2-2 C6M-II rear panel with options installed Note: All external jumpers take precedenc e over menu selection. This includes AUX IF, VIDEO B, SUBCARRIER, and PRGM IF.
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Overview The following table describes the features on the rear panel of the C6M-II modulator. Table 2-3 Description of rear panel connections Feature Description Power line connector. Label indicates input power range. connectors are used to apply comb generator REF OUT REF IN reference signals for phase-locked operation.
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VIDEO B terminal on the rear panel. will be activated in when VIDEO IN B loss of video is detected on if this feature is enabled VIDEO IN A through the menu. These are BNC type coaxial connectors. C6M-II Installation Manual...
Overview The Menu System The C6M-II is operated by menus which are accessed by the four push buttons and the located on the front panel. The relationship of the menus is shown graphically in Figure 2 -3. Figure 2-3 Menu relationships...
If you take no action, the flashing value will revert to the previous value after a short delay. See Appendix C, Changing a Menu Item for a step-by-step description of how to change a menu item. C6M-II Installation Manual...
Video Menu Provides access to the video menu. Press the right arrow key to enter the video menu. Audio Menu Provides access to the audio menu. Press the right arrow key to enter the audio menu. C6M-II Installation Manual...
Automatic Gain Toggles IF AGC between ON (IAGC ON) and OFF Control (IF AGC) (IAGC OFF) For normal operation, it should be on. Manual Gain Control If IF AGC is turned off, MGC is available. (IF MGC) C6M-II Installation Manual...
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Displays the first seven characters of the unit remote control address. The address is same as the serial number. Address is factory programmed and cannot be changed. Address Low Displays the last six characters of the unit remote control address. C6M-II Installation Manual...
Toggles between two different input impedance. LOW indicates a 600 ohm balanced. HI indicates greater than 15 kohms. When the stereo encoder option is in operation, it is set to HI, displays MTS, and cannot be changed. C6M-II Installation Manual...
Toggles between ON and OFF. It must be ON for remote operation. When turned ON, operating parameters cannot be changed locally. Baud rate Displays communication rate. This parameter cannot be changed. Remote type Displays the remote control type. This parameter cannot be changed. C6M-II Installation Manual...
REAR PAN Attempt to change the input source while it is selected through the rear panel terminal block. Input selection by the terminal block has the highest priority. See Appendix D, Signal Priority Chart . C6M-II Installation Manual...
Provided as spares parts for the terminal block. If you are installing the C6M-II in a system that currently has a C6M and will operate in a range higher than 600 MHz, an external lowpass filter, model C6-LPF600 (928-363-000) or equivalent should be included.
Plug the unit into an appropriate power line and allow it to warm up for five minutes. Check that the indicators glow steadily. VIDEO OFF REF OFF Connect a standard baseband video signal generator to the connector on the rear VIDEO IN A " panel. C6M-II Installation Manual...
VIDEO A AUX IF via menu. When the video signal returns and the C6M-II detects its presence, it will switch back to the . To activate this feature, select AUXA ON from the Option menu. VIDEO A...
To activate this feature, select PGMA ON from the Option menu. When the video signal to video A is missing, the C6M-II automatically switches to video B as the backup source. If video B is also missing, the unit can switch to .
Channels 54, 55 and 56 are at the IRC frequencies. Channels 42, 60 and 61 have the + 25 kHz FCC frequency offsets built in. The C6M-II has the capability to output any frequency in increments of 12.5 kHz if needed. If and/or is used in HRC, IF frequency must be 45.7522875 MHz.
Installation Typical Interconnections Basic Video and Audio Interfacing Figure 3-3 shows the standard connections for a video and audio input, and RF output. Figure 3-3 Basic video/audio interfacing C6M-II Installation Manual...
Installation Satellite Link Connection Figure 3-4 shows the connection between the C6R-VCII satellite receiver and the C6M-II. Figure 3-4 Satellite link connection C6M-II Installation Manual...
Installation Satellite Link Connection with C6M-II-SE Figure 3-5 shows the connection between the C6R-VCII satellite receiver and the C6M-II with the Stereo Encoder option installed. Figure 3-5 Satellite link connection with stereo encoder C6M-II Installation Manual...
Measure the RF output and check for the following conditions: If the RF video carrier output is less than 60 dBmV, adjust the RF output on the C6M-II for 60 dBmV. Deactivate the IF AGC on the Option menu display and select auxiliary IF (INPT AUX) on the Main menu as the input.
The CW output is a 45.75 MHz carrier signal that can be used with the MVP II when it is necessary to insert a coherent IF carrier for phase-locked upconversions. Figure 3-7 illustrates the connection of the C6M-II and the MVP II in a phase-locked upconversion.
3-11 Stereo IF Interfacing The CMTS stereo encoder can be used with the C6M-II as shown in Figure 3-7 if the MOB option board is installed. To activate the subcarrier input, select the Input selection menu item INPT SUB on the Main menu or short the subcarrier terminal on the rear panel to the ground terminal.
Menu selection is recommended. The short on the rear panel is not required if the INPT CMP option is selected via the menu. Figure 3-9 External composite baseband connection C6M-II Installation Manual...
Installation 3-13 CMTS / MVP II / C6M-II Connections Figure 3-10 shows the connections between the CMTS, MVP II and C6M-II. Figure 3-10 C6M-II / MVP II / CMTS interfacing C6M-II Installation Manual...
Section 4 System Block Diagrams This section describes the operation of the C6M-II through a series of block diagrams. The text is keyed to letters on the block diagrams. Video to IF Modulation System Figure 4-1 Video to IF modulation system If the modulator option board is installed, baseband video input switching is available.
(VCO). The center frequency of the sound carrier is precisely maintained by a phase-locked loop with an internal 2.0 MHz reference. The audio VCO’s frequency is divided by two to produce the standard 4.5 MHz aural subcarrier C6M-II Installation Manual...
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The subcarrier is mixed with the unmodulated 45.75 MHz signal to create the 41.25 MHz sound IF frequency. The sound IF carrier is bandpass filtered and applied to an amplifier whose gain is controlled by the A/V separation entry on the Main menu. This control sets the desired picture/sound carrier level ratio. C6M-II Installation Manual...
A sample of that signal is provided at a front panel test point at 0 dBmV. With the option package installed, an additional relay is provided. The switch takes its two inputs inputs and delivers its output to the second input of the first from the rear panel PRGM relay switch. C6M-II Installation Manual...
20 dB below actual is brought to a front panel connector for monitoring the final output signal. The RF signal is amplified by a wideband low distortion amplifier module to provide the 60 dBmV specified picture carrier output level. C6M-II Installation Manual...
41.25 MHz Sound IF Output Level 15 to 25 dBmV CW IF Output Frequency 45.75 MHz 50 dBmV ±5 dB CW IF Output Level 30 dBmV ±1 dB @ 87.5% modulation Composite IF Output (picture IF level) Video C6M-II Installation Manual...
+35 to 45 dBmV General ac Voltage Requirements 100 to 240 Vrms, 50 to 60 Hz Power Requirements 40 watts maximum Operating Temperature 0 to 50° C Weight 13.5 lbs maximum Dimensions 19” W x 1.75” H x 17.5” D C6M-II Installation Manual...
If this is the change you want, press the key to implement the change. If you decide not to make the change, do not press . The frequency will return to the previous value after a short delay. C6M-II Installation Manual...
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Press the key to implement a change. Use the left arrow key to exit the menu. If no change is made, the value reverts to the previous setting. C6M-II Installation Manual...
The C6-LPF600 (GI Part No. 928-363-000) is installed either at the RF output of the C6M, or may be installed at the C6M RF combined output before the insertion of channels operating above 600 MHz. Typical installations with the C6M and the C6M-II are displayed below. Figure E-1 Typical installations of C6-LPF600...
Application Notes Specifications Passband Stopband Bandwidth 10 to 600 MHz 600 to 1000 MHz Insertion Loss 2.0 dB maximum –40 dB minimum @ 673 MHz Return Loss –14 dB minimum C6M-II Installation Manual...
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General Instrument Corporation GI Communications Division Printed in U.S.A. 410515-001-99, 3/97...
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Do you have a question about the C6M-II and is the answer not in the manual?
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