User manual DRAKE DIGITAL VMM 600

[. . . ] To obtain such warranty service, the original purchaser must: (1) Retain invoice or original proof of purchase to establish the start of the warranty period. DRAKE COMPANY or the nearest authorized service facility, as soon as possible after discovery of a possible defect, of: (a) the model and serial number, (b) the identity of the seller and the approximate date of purchase; and (c) A detailed description of the problem, including details on the electrical connection to associated equipment and the list of such equipment. DRAKE COMPANY or the nearest authorized service facility, or ship the same in its original container or equivalent, fully insured and shipping charges prepaid. Correct maintenance, repair, and use are necessary to obtain proper performance from this product. [. . . ] Specifications subject to change without notice or obligation. The R. L. Drake VMM 600/VMM 860 Video Modulator System is a professional quality modular headend system designed to optimize rack space. Up to 12 VMM 600 and/or VMM 860 modulators can be racked alongside a single power supply in the Drake 12 position rack mount or up to 4 modulators can be racked in the 4 position rack mount. Either model is a high quality, fixed channel heterodyne audio/ video modulator. The VMM 600 provides a modulated visual and RF carrier output on any single VHF channel 2-13; Lowband channel A8; Midband channel A-I and A5-A1; Superband channel J-W; Hyperband channel AA-ZZ and AAA-XXX (CATV 63-86) or UHF channel 14-35. Aeronautical channels are offset positive with a tolerance of ±5 kHz as required by FCC rules. The VMM 860 provides a modulated visual and RF carrier output on any single Hyperband channel 87-135 or UHF channel 36-69. The heterodyne conversion system, in conjunction with the use of a SAW filter, insures optimum vestigial selectivity for adjacent channel headends. The modulators are designed to accept any standard audio/video source such as NTSC video and audio baseband signals from a satellite receiver, TV camera, videotape recorder, TV demodulator, or similar signal source. The modulators accept standard (sync negative) polarity video at a 0. 7 to 2. 5 Vp-p level. All level controls are located on the front panel for ease of operation. Output level of +45 dBmV is typical and is adjustable from +30 to +45 dBmV. Field-defeatable audio pre-emphasis enables passing of BTSC encoded standard baseband stereo audio signals. The Drake model MMTS20 stereo encoder may be used with the VMM when stereo audio is required. ® is a registered trademark of the R. L. Drake Company P/N: 3852631C-04-2005 2 FRONT PANEL DESCRIPTION F1 REAR PANEL DESCRIPTION R1 INSTALLATION CONNECTIONS AND CONTROLS All connections to and from each modulator are made through the rear panel. Figure 3 illustrates an installation with 12 modulator units combined through a passive signal combiner. Additional channels can be added by using additional VMM 600 or VMM 860 modulators and either multi-por t combiners or combinations of two-port combiners. INSTALLATION NOTES Level adjustment provides optimum performance in multi-channel installations. The modulator outputs should be checked periodically with a spectrum analyzer to maintain a ±1 dB variation of adjacent channel carriers. AUDIO INPUTS AC POWER CORD VIDEO INPUTS VMM 600's/VMM 860's 3 Aural/Visual (A/V) ratios should be held to -15 dB or less. The output `RF' and `A/V (Ratio)' controls are used respectively to make these adjustments. [. . . ] R2 - AUDIO INPUT Connector This is an unbalanced audio input to the IF circuits. This "RCA" (phono) connector input accepts baseband thru 15 kHz audio at a nominal level of 250 mV RMS (approximately 0 dBm). NOTE: An externally accessible test point jumper defeats the audio pre-emphasis for stereo capability. R3 - DC INPUT Connector This 3-pin connector (Male) accepts the appropriate mating DC power cable. [. . . ]