Table of Contents / Description / Specifications 3
2
Caution Statements
2
Important Safety Instructions
3
Table of Contents / Description / Specifications
4
Front Panel Controls and Indicators
5
Rear Panel Controls and Connections
VM2860 VIDEO MODULATOR
POWER
NORMAL
OVER-MOD
VIDEO
LEVEL
NORMAL
OVER-MOD
AUDIO
LEVEL
A / V RATIO
RF OUTPUT
EAS ACTIVE
CATV
CATV +
100
CHANNEL
2
5
6
Installation / Installation Diagram
7
Channel Assignments
9
Internal Jumper Settings
10 Service / If You Need To Call For Help
11 Warranty
SPECIFICATIONS - VM2860 / VM2862
TABLE OF CONTENTS
RF
Frequency Range:
FCC Offsets:
Output Level:
Amplitude Stability:
Output Impedance:
A/V Ratio:
Frequency Stability:
Spurious Outputs:
Phase Noise:
Output Filter Bands:
Broadband Noise:
VIDEO
Input Level:
Input Impedance:
Frequency Response:
In-channel C/N:
L/C Delay:
Differential Gain:
Differential Phase:
MONO AUDIO
Input Level:
Input Impedance:
54 MHz to 864 MHz.
Standard CATV channels 2 to 135.
Broadcast, HRC, and IRC channel plans available by
internal jumper.
Automatic, positive.
+60 dBmV minimum, 12 dB minimum adjustment
range.
± 1 dB.
75 Ohms, 12 dB return loss within output filter
passband.
-12 dB to -25 dB.
± 5 ppm. All oscillators locked to the same internal
reference.
-60 dBc at +60 dBmV output level, 5 MHz to
1000 MHz, 15 dB A/V ratio.
-85 dBc at 10 kHz offset.
54 MHz to 258 MHz, 258 MHz to 462 MHz, 462 MHz
to 660 MHz, 660 MHz to 864 MHz.
-80 dBc, 4 MHz bandwidth, +60 dBmV output level,
±18 MHz offset within output filter passband, -90 dBc
outside of output filter passband, output filtered into 4
approximately 200 MHz wide bands.
1 Vp-p ± 3 dB, manual gain adjustment with
modulation indicators.
75 Ohms, 25 dB return loss.
20 Hz to 4.2 MHz, ± 1 dB with 4.5 MHz trap off,
20 Hz to 4.1 MHz, ±1 dB with 4.5 MHz trap on.
65 dB.
±50 nS of FCC predistortion with 4.5 MHz trap off,
-20 +80 nS of FCC predistortion with 4.5 MHz trap on.
± 3%.
± 3
0
.
250 mVrms to 2.5 Vrms, manual gain adjustment with
LED modulation indicators.
10K Ohms, unbalanced.
An auto-switching alternate IF input, labeled EAS input, is provided
for connection of an Emergency Alert System 44 MHz IF signal.
When the EAS IF signal appears at the EAS input, the main video
and audio modulated IF is replaced by the EAS input signal.
A 4.5 MHz video trap may be selected via an internal jumper
(VM2862 has 4.5 MHz trap on as factory setting). This may be used
to filter off a 4.5 MHz sound subcarrier or undesired video
components to prevent interference to the stereo or SAP channels.
The RF section of the modulator contains bandpass filtering that
divides the 54 to 862 MHz output range into four bands, each
approximately 200 MHz wide. This filtering, in conjunction with the
use of high level, low noise floor mixing, ensures very low
broadband noise at the output. Thus a full complement of up to all
134 available channels from VM2860 or VM2862 modulators may
be combined while maintaining an excellent C/N of each channel.
All of the mentioned features, combined with a carefully designed
low noise and low distortion output stage, provide reliable operation
in a densely crowded SMATV or CATV environment.
The inclusion of a fan in the VM2860 and VM2862 permits rack
mounting of this equipment without leaving the typical 1U air space
between modulators.
75
µ
S.
50 Hz to 15 kHz, ±1 dB.
0.5% maximum.
65 dB.
(VM2862 only)
250 mVrms to 2.5 Vrms, manual gain adjustment with
LED modulation indicators.
10K Ohms, unbalanced.
30 db, 50 Hz to 12.5 kHz; 25 dB, 12.5 kHz to 14 kHz.
± 0.5 dB, 50 Hz to 14 kHz.
0.5% maximum.
65 dB.
(VM2862 only)
250 mVrms to 2.5 Vrms, manual gain adjustment with
over-modulation indicator.
10K Ohm, unbalanced.
±2 dB, 50 Hz to 10 kHz.
1% maximum.
80 dB.
+30 dBmV, ±1 dB (visual carrier).
75 Ohm, 20 dB return loss.
60 dB.
+20 dBmV.
115 VAC ± 10%, 60 Hz,
23 Watts (VM2860), 28 Watts (VM2862).
1/2 Amp Slo-Blo 5 X 20 mm.
0° to 50° C.
Internal 1.85 CFM fan allows operation in the rack
without air spaces between units.
FCC Part 15.
11.25" D x 1.75" H x 19" W
8 lbs. 8 oz.
DESCRIPTION
The R.L Drake VM2860 and VM2862 Video Modulators are high
quality, vestigial sideband units with synthesized visual and aural
carriers. They are designed to accept NTSC video and audio
baseband signals from a satellite receiver or similar equipment.
Front panel video and audio level controls with accompanying
modulation indicators permit easy setup of the proper modulation
levels. The A/V ratio and RF output level controls are also provided
on the front panel. A rear panel EAS alternate IF input is also
provided. The VM2860 model is for applications with mono audio
and the VM2862 model provides BTSC stereo encoded audio. If
SAP is required, this option is available for the VM2862 model, and
is field installable.
Synthesized operation provides complete frequency agility, allowing
front panel selection of any standard CATV channel from 2 to 135
(54 to 862 MHz band). FCC required offsets for aeronautical
channels are automatically provided for each channel that requires
an offset. For special applications, IRC or HRC CATV frequencies
or off-air broadcast frequencies can be selected after moving an
internal jumper.
A high quality IF SAW filter with FCC predistortion eliminates
adjacent channel interference and provides optimum delay
characteristics.
MONO AUDIO, cont'd.
Pre-emphasis:
Frequency Response :
THD:
S/N:
BTSC STEREO AUDIO
Input Level:
Input Impedance:
Separation:
Frequency Response:
THD:
S/N:
SAP AUDIO Option
Input Level:
Input Impedance:
Frequency Response:
THD:
S/N:
EAS INPUT
Level :
Impedance:
Isolation:
Auto Switching Level:
GENERAL
AC Power:
Fuse:
Temperature Range:
Cooling:
Radiated Emissions:
Size:
Weight:
