Specifications

www.tvcinc.com
Section 1: Headend Equipment
Modulators
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1 - 27
Frequency Agile Modulators
The HMA-500 and the HMA-860 series are high quality SAW filtered, frequency agile modulators specifically designed to
meet the highest CATV performance standards. All channels are easily selected by front panel switches and verified by an
easy-to-read LED channel display. The modulators feature an extremely low out of band noise level allowing their use in
larger channel head-ends. The user-friendly front panel controls make the HMA-500 and the HMA-860 series modulators
the ideal choice for any system where performance, reliability, and affordability are required.
• 50 or 60 dBmV Output Models
• Low Out-Of-Band Noise
• SAW Filtered
• Easy-to-Read LED Channel Display
• Overmodulation Indicators
Ordering Information • HMA-500 • HMA-500H • HMA-860 • HMA-860H
• Crystal Referenced PLL Tuning
• Switching Power Supply (Operates from 90–260VAC)
• BTSC Stereo Compatible (Built-in Encoder Available)
• I.F. Loop
VM2551 Agile Commercial Video Modulator
The R.L. Drake Company now offers you superior performance and extensive channel capacity with the VM2551 agile video
modulator. Another quality product from Drake, the VM2551 is a vestigial sideband, agile modulator with synthesized visual
and aural carriers and a full +55 dBmV output level. Designed to accept composite NTSC video and audio inputs from a
satellite receiver, video server, off-air demodulator, DVD player, VCR, or similar source, the VM2551 features front panel
video and audio over-modulation indicators and level controls to permit easy setup of modulation levels.
The use of frequency synthesis provides complete frequency agility in the range of 54 to 550 MHz using off-air or CATV
(STD, IRC, or HRC) channel plans. In compliance with FCC regulations, channels that fall in specified aeronautical bands
feature automatic frequency offset. The use of a superior SAW filter in the IF circuitry allows adjacent channel operation
when used with other modulators or signal sources. A composite IF loop following the SAW filter and before signal conver-
sion to the final RF output channel allows the insertion of scrambling equipment or an IF switch to provide switchover for
EAS operation.
If required, the audio preemphasis may be defeated to allow use with a baseband stereo encoder or the normal internally
generated aural carrier can be disabled and an externally sourced 4.5 MHz signal can be applied to the rear panel input.
These features, combined with a carefully designed low distortion output stage, provide reliable and economical perfor-
mance in an adjacent channel +55 dBmV cable television or private cable environment.
• A popular priced agile NTSC modulator.
• Frequency agility with 82 channel coverage from 54
MHz to 550 MHz.
• CATV (STD, HRC or IRC) or off-air channel plans
selectable from front panel.
• Front panel control of channel selection, video level,
audio level, output level, and A/V ratio.
• High output power to +55 dBmV.
• Designed for multiple modulator installations.
• Emergency Alert System (EAS) ready with IF composite
loop.
• Composite IF loop to accommodate a variety of encryp-
tion systems.
• Audio and Video LED overmodulation indicators.
• Automatic channel offsets where specified by FCC
regulations.
• SAW filtering to ensure quality performance.
• External source 4.5 MHz aural input.
• Defeatable pre-emphasis for use with baseband stereo
encoders.
• Front panel monitor connection at -30dB
Ordering Information:....................VM2551
Holland
Electronics LLC