User manual DRAKE DIGITAL VM1550

[. . . ] VM1550 Commercial Video Modulator (For use in NTSC systems) Instruction Manual ® is a registered trademark of the R. L. Drake Company P/N - 3857400K-3-2002 Printed in U. S. A. 2 Caution Statements WARNING: TO PREVENT FIRE OR ELECTRICAL SHOCK DO NOT EXPOSE TO RAIN OR MOISTURE A product and cart combination should be moved with care. Quick stops, excessive force and uneven surfaces may cause the product and cart combination to overturn. The lightning flash with arrow head symbol, within an equilateral triangle, is intended to alert the user to the presence of uninsulated "dangerous voltage" within the product's enclosure that may be of sufficient magnitude to constitute a risk of electric shock to persons. [. . . ] Spurious Outputs: -65 dBc minimum, measured at -15 dB A/V ratio and with modulator output level of +45 dBmV. Video S/N: 60 dB minimum, luminance weighted. 5 L/C Delay: ±35 nSec referenced to 0 nSec L/C delay (complies with FCC rules, 76. 605). Frequency Response: 20 Hz to 15 kHz, ± 1 dB, referenced to 75 µSec pre-emphasis curve. The aural carrier should be adjusted to approximately 15 dB below the visual carrier (normal operation). Clockwise rotation increases the aural carrier level and thus decreases the A/V ratio. F7 - CHANNEL Designation The label indicates the fixed channel output for your particular model. The VM1550 is capable of fixed channel output within the following ranges: VHF, 2-13; Lowband 1 (A8): Midband, 14-22 (A-I) and 95-99 (A5-A1); Superband, 23-36 (J-W); Hyperband, 37-44 (AA-HH); F8 - RF OUTPUT LEVEL This screwdriver adjustment permits decreasing the RF output level a minimum of 12 dB below its specified output level as the control is rotated counterclockwise. The maximum output level of +45 dBmV is set with the adjustment fully clockwise. NOTE: If an output level of less than +35 dBmV is required, add an attenuator of the appropriate value at the modulator output. Example: For an output level of +30 dBmV, add a 10 dB attenuator pad to the modulator output. Rear Panel Connections 7 MADE IN U. BY ® COMPOSITE IF RF OUT IN OUT - RISK OF FIRE -REPLACE FUSE AS MARKED AFTER DISCONNECTING UNIT FROM AC LINE CAUTION: VIDEO INPUT AUDIO INPUT FUSE 1/8A, 250V SLO-BLO 600 WATTS MAX 115V 60 Hz 10 WATTS ATTENTION: - RISQUE D'INCENDIE REMPLACEZ FUSIBLE DU TYPE INDIQUE APRES DEBRANCHER DU SECTEUR 120V, 5A R1 R2 R3 R4 R5 R6 R7 R8 R1 - RF OUT This is the modulator output. R2 - COMPOSITE IF INPUT Connector This is the composite IF input to the heterodyne converter. This connection is normally cabled directly to the "COMPOSITE IF OUT" connector (See Item `R3'). This external IF loop allows the use of accessories such as scramblers or alternate video sources. Note that accessory equipment must also have the visual carrier at 45. 75 MHz and the aural carrier at 41. 25 MHz. R3 - COMPOSITE IF OUTPUT Connector This is the composite IF output from the IF circuits. The composite IF provides a vestigial sideband filtered visual carrier at 45. 75 MHz combined with a level controlled (-15 dBc typical) aural carrier at 41. 25 MHz. This connection is normally cabled directly to the "COMPOSITE IF IN" connector (See Item `R2'). R4 - VIDEO INPUT Connector This is the baseband video input to the IF circuits. This input accepts baseband thru 4. 2 MHz video at levels from 0. 7 Vp-p to 1. 5 Vp-p. R5 - AUDIO INPUT Connector This is an unbalanced audio input to the IF circuits. This "RCA" (phono) connector input accepts baseband through 15 kHz audio at a nominal level of 250 mV RMS (approximately 0 dBm). NOTE: An internally selected test point jumper defeats the audio pre-emphasis for stereo capability. R6 - FUSE Always replace this fuse with one of the same type and rating: 1/8 Amp, 250 V SLO-BLO® , 3AG type. [. . . ] The unit must be sent to the following address: Service Department R. L. Be sure to include your street address which will be needed for UPS return. UPS Surface (Brown Label) takes 7-10 days to reach us depending on your location, Blue takes 2-3 days. Red is an overnight service. Send the unit in a way that it can be traced if we can't verify receipt of shipment. [. . . ]