3-8 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
Installation 3-9 Video Scrambling The C6M-II can be connected to a General Instrument Modulating Video Processor (MVP II) for video and audio scrambling as displayed in Figure 3-6. Note: General Instrument recommends using the C6U dual upconverter to interface with the MVP II. Figure 3-6 MVP II / C6M-II IF interfacing When connecting the MVP II to the C6M-II, use the IF set up in the MVP II Installation Manual and the following steps for connecting the C6M-II: Verify that the MVP II is in standby mode. Select video A input (INPT VA) on the Main menu and activate IF AGC on the Option menu display Tune to a test channel. Ensure that appropriate test equipment is connected to RF OUT on the rear panel. 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. When sync suppression scrambling is used, IF AGC must be turned off in the C6M-II Monitor the test equipment to verify 60 dbmv is still present at the RF output.
3-10 Installation If the RF level is not 60 dbmv, the COMP IF control on the MVP II can be adjusted. Do not exceed 32 dbmv at the IF output of the MVP II. If the RF level is still not 60 dbmv, use manual IF gain control on the Option menu to set RF level. Do not use RF level control to set the RF output level at this stage. CW Output 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. Figure 3-7 MVP II / C6M-II interfacing using the CW output
Installation 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. Use the level adjustment on the CMTS front panel to adjust the RF output sound carrier level. Figure 3-8 C6M-II / CMTS IF interfacing
3-12 Installation Composite Baseband Interfacing If the MOB option board is installed, an external composite baseband can be accepted. To use the external composite baseband input, connect the unit as shown in Figure 3-9. To activate, select the Input selection menu item INPT CMP 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
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
3-14 Installation C6R-VCII / CMTS / MVP II / C6M-II Connections Figure 3-11 shows the connections between the C6R-VCII, CMTS, MVP II and C6M-II. Figure 3-11 C6R-VCII / CMTS / MVP II / C6M-II connections
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 A B C D E F G H If the modulator option board is installed, baseband video input switching is available. The video switch includes a Video A level sensor which automatically switches to Video B when the Video A signal level is low or absent. Audio input switching follows the video input selection. A rear panel connection provides external control. Video AGC is provided with the modulator option board for use with varying video signal levels and when switching between video sources at different levels. The video system is applied to a dc clamp circuit. The dc clamp can be disabled through the menu. The clamped signal is applied to a variable gain stage to permit depth of modulation adjustment. Video modulation is controlled through the video modulation entry on the main menu. A dual diode bridge circuit provides amplitude modulation. The modulated IF output is buffered and then applied to an all-pass delay equalizer which corrects the total group delay response error generated by the C6M-II system. The signal is bandpass filtered to remove unwanted frequencies at the PIF OUT connector on the rear panel. The unmodulated 45.75 MHz carrier is generated by a phase-locked loop which locks a voltage controlled oscillator to an internal 2 MHz reference.
4-2 System Block Diagrams Audio to IF Modulation System Figure 4-2 Audio to IF modulation system A B C D E F G H Left and right audio signals are encoded per BTSC standards when the stereo encoder option is installed. If the modulator option board is installed, audio switching is provided. The audio input will follow the switched video input. The audio input range is selected from the Audio range (AUDR) entry on the Audio menu. Either the low range (AUDR LOW) which is 10 to +10 dbm, or the high range (AUDR HI) which is +5 to +25 dbm, may be selected. The audio input impedance is selected from the Audio impedance (AUDZ) entry on the Audio menu. Either low impedance (AUDZ LOW) which is 600 Ohms balanced, or high impedance (AUDZ HI) which is 15 kohms, may be selected. A variable gain stage sets the FM deviation to the required ±25 khz. This can be adjusted through the Audio deviation entry on the Main menu. An optional AGC capability is provided for situations involving an unstable audio source or switching between audio sources of different levels. This capability is enabled through the Audio AGC entry on the Audio menu. The standard broadcast television pre-emphasis can be disabled. Frequency modulation is accomplished by applying the processed audio signal to a 9.0 MHz voltage controlled oscillator (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
System Block Diagrams 4-3 frequency. I J K An optional external 4.5 MHz input switch is furnished to utilize a 4.5 MHz audio source. 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.
4-4 System Block Diagrams IF Switching and AGC System Figure 4-3 IF switching and AGC system A B C D E F G H I J The picture IF signal input is taken from the rear panel connectors. This signal is amplified to compensate for the loss of the surface acoustic wave (SAW) filter that follows. This filter generates the required television vestigial sideband response shape and eliminates unwanted frequencies. The sound IF signal input is taken from the rear panel connectors. A SAW bandpass filter removes unwanted frequencies. The filtered IF signals are combined to produce a composite IF signal. The signal is split and buffered. One of the signals is a composite IF output while the other is fed to a two-input IF relay switch. When not in use, the composite IF output should be terminated with 75 Ohms. The second input to the relay is normally from the AUX-IF input connector. After IF switching operations, the signal is applied to the Automatic IF Level Control (ALC) subsystem. This circuit assures constant input level to the output converter system when switching between IF signal sources that do not have equal level. The ALC function can be disabled when required for processing non-standard signals. The composite IF signal is buffered and filtered to remove any spurious signals and delivered to the IF-to-channel converter system input. 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 from the rear panel AUX-IF and PRGM-IF inputs and delivers its output to the second input of the first relay switch.
System Block Diagrams 4-5 IF to Channel Converter System Figure 4-4 IF to channel converter system A B C D E F G H The IF input signal is applied to the first mixer. The local oscillator signal for the first mixer is generated by a voltage-controlled oscillator that is PLL controlled. The PLL frequency is programmed by the microprocessor to accommodate the selected channel plan or frequency setting. The local oscillator mixes with the IF input to produce the high IF which is then bandpass filtered and amplified. The high IF is applied to the second mixer. The circuit for the second local oscillator must be tunable over a 1000 MHz range to produce RF output picture carrier frequencies. The microprocessor programs the second LO PLL according to the channel or frequency setting. The channel frequency output signal from the second mixer is applied to a variable loss PIN attenuator. The circuit s loss is controlled by the RF output level entry on the Main menu. This permits trimming of the combined headend system carrier level for each channel. The signal is applied to the output bandpass filter bank. The appropriate filter is selected based on the selected channel number. The filter system minimizes the broadband output noise and allows unlimited broadband combining without need for external filters. The system maintains a combined headend carrier-to-noise ratio of 60 db. The RF output signal is supplied to the rear panel while a sample at 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.
Appendix A Specifications RF Output Channels Frequency Range Frequency Accuracy Output Level Recommended operating range Spurious Output Return Loss Sound Carrier Level (adjustable) C/N Ratio (normalized to 4 MHz) In-band Adjacent Channel Wideband 2 to 161 (HRC, IRC, STD, EIA frequency plans or 12.5 khz steps) 50 to 1000 MHz ±5 khz maximum, ±500 Hz typical +60 dbmv minimum 57 to 61 dbmv 60 dbc minimum @ 60 dbmv (50 to 1000 MHz) with sound carrier at 15 dbc 14 db minimum within channel (50 to 750 MHz) 13 db minimum within channel (750 to 1000 MHz) 10 to 20 db relative to video carrier 68.0 db minimum, 70.0 db typical 72.0 db minimum, 74.0 db typical 75.5 db minimum, 76.0 db typical IF Picture IF Output Frequency Picture IF Output Level Sound IF Output Frequency Sound IF Output Level CW IF Output Frequency CW IF Output Level Composite IF Output (picture IF level) 45.75 MHz 35 dbmv @ 87.5% modulation 41.25 MHz 15 to 25 dbmv 45.75 MHz 50 dbmv ±5 db 30 dbmv ±1 db @ 87.5% modulation Video
A-2 Specifications Standard Baseband Input Encoded Video Input Level Video Input Impedance Video Input Return Loss K Factor S/N Ratio (lum. weighted) Chroma Delay, relative to standard precorrection Frequency Response Differential Gain Differential Phase Tilt 0.5 to 2.0 Vp-p for 87.5% modulation 1.0 Vp-p for 87.5% modulation 75 Ohms 30 db minimum 2% maximum 64 db minimum ±50 nsec ±0.5 db from 0 to 4.1 MHz ±3% @ 87.5% modulation 1.0 degree p-p maximum @ 87.5% modulation 1% maximum Audio Input Level Range Low High Input Impedance Low High Frequency Response Preemphasis Harmonic Distortion Hum and Noise Subcarrier Frequency Subcarrier Input Level 10 to +10 dbm, Z 0 = 600 Ohm +5 to +25 dbm, Z 0 = 600 Ohm 600 Ohms balanced 15 kohms minimum ±1.0 db from 30 Hz to 15 khz 75 µsec, defeatable 1% maximum from 30 Hz to 15 khz at ±25 khz 60 dbc maximum with ±25 khz 4.5 MHz ±500 Hz +35 to 45 dbmv General ac Voltage Requirements Power Requirements Operating Temperature Weight Dimensions 100 to 240 Vrms, 50 to 60 Hz 40 watts maximum 0 to 50 C 13.5 lbs maximum 19 W x 1.75 H x 17.5 D
Appendix B Frequency Plan GI Channel Number Picture Carrier Frequency (MHz) EIA Channel Historical Reference HRC IRC Standard EIA 2 54.0027 55.2625 55.2500 55.2500 2 3 60.0030 61.2625 61.2500 61.2500 3 4 66.0033 67.2625 67.2500 67.2500 4 5 78.0039 79.2625 77.2500 77.2500 5 A-7 6 84.0042 85.2625 83.2500 83.2500 6 A-6 7 174.0087 175.2625 175.2500 175.2500 7 8 180.0090 181.2625 181.2500 181.2500 8 9 186.0093 187.2625 187.2500 187.2500 9 10 192.0096 193.2625 193.2500 193.2500 10 11 198.0099 199.2625 199.2500 199.2500 11 12 204.0102 205.2625 205.2500 205.2500 12 13 210.0105 211.2625 211.2500 211.2500 13 14 120.0060 121.2625 121.2625 121.2625 14 A 15 126.0063 127.2625 127.2625 127.2625 15 B 16 132.0066 133.2625 133.2625 133.2625 16 C 17 138.0069 139.2625 139.2500 139.2500 17 D 18 144.0072 145.2625 145.2500 145.2500 18 E 19 150.0075 151.2625 151.2500 151.2500 19 F 20 156.0078 157.2625 157.2500 157.2500 20 G 21 162.0081 163.2625 163.2500 163.2500 21 H 22 168.0084 169.2625 169.2500 169.2500 22 I 23 216.0108 217.2625 217.2500 217.2500 23 J 24 222.0111 223.2625 223.2500 223.2500 24 K 25 228.0114 229.2625 229.2625 229.2625 25 L 26 234.0117 235.2625 235.2625 235.2625 26 M 27 240.0120 241.2625 241.2625 241.2625 27 N
B-2 Frequency Plan GI Channel Number Picture Carrier Frequency (MHz) EIA Channel Historical Reference HRC IRC Standard EIA 28 246.0123 247.2625 247.2625 247.2625 28 O 29 252.0126 253.2625 253.2625 253.2625 29 P 30 258.0129 259.2625 259.2625 259.2625 30 Q 31 264.0132 265.2625 265.2625 265.2625 31 R 32 270.0135 271.2625 271.2625 271.2625 32 S 33 276.0138 277.2625 277.2625 277.2625 33 T 34 282.0141 283.2625 283.2625 283.2625 34 U 35 288.1440 289.2625 289.2625 289.2625 35 V 36 294.0147 295.2625 295.2625 295.2625 36 W 37 300.0150 301.2625 301.2625 301.2625 37 X 38 306.0153 307.2625 307.2625 307.2625 38 Y 39 312.0156 313.2625 313.2625 313.2625 39 Z 40 318.0159 319.2625 319.2625 319.2625 40 DD 41 324.0162 325.2625 325.2625 325.2625 41 EE 42 330.0165 331.2750 331.2750 331.2750 42 FF 43 336.0168 337.2625 337.2625 337.2625 43 GG 44 342.0171 343.2625 343.2625 343.2625 44 HH 45 348.0174 349.2625 349.2625 349.2625 45 II 46 354.0177 355.2625 355.2625 355.2625 46 JJ 47 360.0180 361.2625 361.2625 361.2625 47 KK 48 366.0183 367.2625 367.2625 367.2625 48 LL 49 372.0186 373.2625 373.2625 373.2625 49 MM 50 378.0189 379.2625 379.2625 379.2625 50 NN 51 384.0192 385.2625 385.2625 385.2625 51 OO 52 390.0195 391.2625 391.2625 391.2625 52 PP 53 396.0198 397.2625 397.2625 397.2625 53 QQ 54 72.0036 73.2625 73.2500 55 78.0039 79.2625 79.2500 56 84.0042 85.2625 85.2500 57 90.0045 91.2625 91.2500 91.2500 95 A-5 58 96.0048 97.2625 97.2500 97.2500 96 A-4
Frequency Plan B-3 GI Channel Number Picture Carrier Frequency (MHz) EIA Channel Historical Reference HRC IRC Standard EIA 59 102.0051 103.2625 103.2500 103.2500 97 A-3 60 108.0054 109.2750 109.2750 109.2750 98 A-2 61 114.0057 115.2750 115.2750 115.2750 99 A-1 62 402.0201 403.2625 403.2500 403.2500 54 RR 63 408.0204 409.2625 409.2500 409.2500 55 SS 64 414.0207 415.2625 415.2500 415.2500 56 TT 65 420.0210 421.2625 421.2500 421.2500 57 UU 66 426.0213 427.2625 427.2500 427.2500 58 VV 67 432.0216 433.2625 433.2500 433.2500 59 WW 68 438.0219 439.2625 439.2500 439.2500 60 XX 69 444.0222 445.2625 445.2500 445.2500 61 YY 70 450.0225 451.2625 451.2500 451.2500 62 ZZ 71 456.0228 457.2625 457.2500 457.2500 63 72 462.0231 463.2625 463.2500 463.2500 64 73 468.0234 469.2625 469.2500 469.2500 65 74 474.0237 475.2625 475.2500 475.2500 66 75 480.0240 481.2625 481.2500 481.2500 67 76 486.0243 487.2625 487.2500 487.2500 68 77 492.0246 493.2625 493.2500 493.2500 69 78 498.0249 499.2625 499.2500 499.2500 70 79 504.0252 505.2625 505.2500 505.2500 71 80 510.0255 511.2625 511.2500 511.2500 72 81 516.0258 517.2625 517.2500 517.2500 73 82 522.0261 523.2625 523.2500 523.2500 74 83 528.0264 529.2625 529.2500 529.2500 75 84 534.0267 535.2625 535.2500 535.2500 76 85 540.0270 541.2625 541.2500 541.2500 77 86 546.0273 547.2625 547.2500 547.2500 78 87 552.0276 553.2625 553.2500 553.2500 79 88 558.0279 559.2625 559.2500 559.2500 80 89 564.0282 565.2625 565.2500 565.2500 81
B-4 Frequency Plan GI Channel Number Picture Carrier Frequency (MHz) EIA Channel Historical Reference HRC IRC Standard EIA 90 570.0285 571.2625 571.2500 571.2500 82 91 576.0288 577.2625 577.2500 577.2500 83 92 582.0291 583.2625 583.2500 583.2500 84 93 588.0294 589.2625 589.2500 589.2500 85 94 594.0297 595.2625 595.2500 595.2500 86 95 600.0300 601.2625 601.2500 601.2500 87 96 606.0303 607.2625 607.2500 607.2500 88 97 612.0306 613.2625 613.2500 613.2500 89 98 618.0309 619.2625 619.2500 619.2500 90 99 624.0312 625.2625 625.2500 625.2500 91 100 630.0315 631.2625 631.2500 631.2500 92 101 636.0318 637.2625 637.2500 637.2500 93 102 642.0321 643.2625 643.2500 643.2500 94 103 648.0324 649.2625 649.2500 649.2500 100 104 654.0327 655.2625 655.2500 655.2500 101 105 660.0330 661.2625 661.2500 661.2500 102 106 666.0333 667.2625 667.2500 667.2500 103 107 672.0336 673.2625 673.2500 673.2500 104 108 678.0339 679.2625 679.2500 679.2500 105 109 684.0342 685.2625 685.2500 685.2500 106 110 690.0345 691.2625 691.2500 691.2500 107 111 696.0348 697.2625 697.2500 697.2500 108 112 702.0351 703.2625 703.2500 703.2500 109 113 708.0354 709.2625 709.2500 709.2500 110 114 714.0357 715.2625 715.2500 715.2500 111 115 720.0360 721.2625 721.2500 721.2500 112 116 726.0363 727.2625 727.2500 727.2500 113 117 732.0366 733.2625 733.2500 733.2500 114 118 738.0369 739.2625 739.2500 739.2500 115 119 744.0372 745.2625 745.2500 745.2500 116 120 750.0375 751.2625 751.2500 751.2500 117
Frequency Plan B-5 GI Channel Number Picture Carrier Frequency (MHz) EIA Channel Historical Reference HRC IRC Standard EIA 121 756.0378 757.2625 757.2500 757.2500 118 122 762.0381 763.2625 763.2500 763.2500 119 123 768.0384 769.2625 769.2500 769.2500 120 124 774.0387 775.2625 775.2500 775.2500 121 125 780.0390 781.2625 781.2500 781.2500 122 126 786.0393 787.2625 787.2500 787.2500 123 127 792.0396 793.2625 793.2500 793.2500 124 128 798.0399 799.2625 799.2500 799.2500 125 129 804.0402 805.2625 805.2500 805.2500 126 130 810.0405 811.2625 811.2500 811.2500 127 131 816.0408 817.2625 817.2500 817.2500 128 132 822.0411 823.2625 823.2500 823.2500 129 133 828.0414 829.2625 829.2500 829.2500 130 134 834.0417 835.2625 835.2500 835.2500 131 135 840.0420 841.2625 841.2500 841.2500 132 136 846.0423 847.2625 847.2500 847.2500 133 137 852.0426 853.2625 853.2500 853.2500 134 138 858.0429 859.2625 859.2500 859.2500 135 139 864.0432 865.2625 865.2500 865.2500 136 140 870.0435 871.2625 871.2500 871.2500 137 141 876.0438 877.2625 877.2500 877.2500 138 142 882.0441 883.2625 883.2500 883.2500 139 143 888.0444 889.2625 889.2500 889.2500 140 144 894.0447 895.2625 895.2500 895.2500 141 145 900.0450 901.2625 901.2500 901.2500 142 146 906.0453 907.2625 907.2500 907.2500 143 147 912.0456 913.2625 913.2500 913.2500 144 148 918.0459 919.2625 919.2500 919.2500 145 149 924.0462 925.2625 925.2500 925.2500 146 150 930.0465 931.2625 931.2500 931.2500 147 151 936.0468 937.2625 937.2500 937.2500 148
B-6 Frequency Plan GI Channel Number Picture Carrier Frequency (MHz) EIA Channel Historical Reference HRC IRC Standard EIA 152 942.0471 943.2625 943.2500 943.2500 149 153 948.0474 949.2625 949.2500 949.2500 150 154 954.0477 955.2625 955.2500 955.2500 151 155 960.0480 961.2625 961.2500 961.2500 152 156 966.0483 967.2625 967.2500 967.2500 153 157 972.0486 973.2625 973.2500 973.2500 154 158 978.0489 979.2625 979.2500 979.2500 155 159 984.0492 985.2625 985.2500 985.2500 156 160 990.0495 991.2625 991.2500 991.2500 157 161 996.0498 997.2625 997.2500 997.2500 158
Appendix C Changing a Menu Item The following example illustrates how to change the frequency. Display the frequency on the Main menu as described in Section 2, Overview. The illustration below shows the frequency 503.2625. 1 Press the right arrow key. In this case, the digit 3 flashes as shown below. Press the up arrow key. The digit 4 appears and flashes as shown below. If this is the change you want, press the ENT key to implement the change. If you decide not to make the change, do not press ENT. The frequency will return to the previous value after a short delay.
C-2 Changing a Menu Item If you wish to return to the previous value immediately, press the left arrow key until the previous value appears. In this case the left arrow key is pressed three times, and, as shown below, the 0 flashes, the 5 flashes, and then the previous value appears. A summary: To reach any item in a menu To get into a submenu (e.g., Option) To get out of a submenu To change a menu item Use the up or down arrow key (menu wraps vertically). Use the right arrow key. Use the left arrow key. Use the right arrow key to cause the item to flash. Use the up or down arrow key until the desired value or function is reached. Press the ENT 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.
Appendix D Signal Priority Chart
D-2 Signal Priority Chart
Signal Priority Chart D-3
D-4 Signal Priority Chart
Signal Priority Chart D-5
Appendix E Application Notes C6-LPF600 This application note is to assist you in the operation of the C6M in headends operating above 600 MHz. Summary The C6M incorporates a dual high IF conversion technique that minimizes spurious and distortion products within the 50 to 600 MHz operating bandwidth of the C6M. The high IF local oscillator, which is used to downconvert the high IF to the desired output RF carriers, operates above 600 MHz. This local oscillator frequency may be present at the C6M RF output and may cause interference with analog and digital channels, or data carriers operating above 600 MHz. To minimize this potential problem, install a C6-LPF600. The C6-LPF600 is a high performance, low-pass filter (10 to 600 MHz) that may be used to attenuate spurious carriers occurring at 600 MHz and above frequencies. The specifications on this filter are included with this application note. Discussion 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
E-2 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 N/A
General Instrument Corporation GI Communications Division Printed in U.S.A. 410515-001-99, 3/97