Olson Technology OTM-3550-SW User Manual
OTM-3550-SW
FREQUENCY AGILE F.C.C. COMPATIBLE
TELEVISION MODULATOR
INSTRUCTION MANUAL
Phone:
E-Mail: salessupport@olsontech.com
025-000233 REV E 8/17/01
(209) 586-1022
(800) 545-1022
Fax:
(209) 586-1026
www.olsontech.com
OTM-3550-SW
SPECIFICATIONS
Output Frequency Range........................................
Output Level..........................................................
Frequency Accuracy/Stability ..................................
Out-of-Band C/N Ratio.........................................
Spurious Output.....................................................
I.F . Output Frequency ............................................
V ideo IF Level.......................................................
V ideo Carrier Level................................................
V ideo Performance................................................
Audio Intercarrier Stability ......................................
Audio Deviation.....................................................
Audio/V ideo Ratio.................................................
Front Panel Controls..............................................
Front Panel Indicators............................................
Rear Panel Connectors...........................................
Power Consumption...............................................
Fuse......................................................................
Size.......................................................................
Selectable in .25MHz increments.
7.00MHz, Ch. T7 to 547.25MHz, Ch. 78
+55dBmV min., 15.0 - 547.25MHz;
+52dBmV min., 7.0MHz
<±5KHz of selected channel frequency
>80dB as measured in a 4.0MHz noise bandwidth.
>55dB down @ 55dBmV output, 15.00 to
547.25MHz;
>55dB down @ 52dBmV output, 7.0MHz
V ideo 45.75MHz, audio 41.25MHz
+40dBmV
Adjustable downward by 10dB minimum.
Measured @ 80% modulation. Differential gain
<6%. Differential phase <3°. V ideo input 1 volt
p-p (75Ω). 170 nSec predistortion, ± 40nSec.
<±1KHz
25KHz - 75 µsec pre-emphasis. Minimum 500mV
p-p input.
Adjustable from 12dB to 20dB below video carrier .
Channel/F .C.C. offset, video/audio modulation,
R.F . level and A/V ratio.
LED’s for video/audio overmodulation.
75Ω type F: V ideo input, RF output, -20dB test
point and video/audio IF loops. T erminal strip:
600Ω balanced audio input. 3-wire power cord/USA plug.
115 VAC @ 60Hz - 15 watts.
0.5 amp Slo-blo
1.75" H x 19" W x 8" D.
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1) INTRODUCTION
The Olson T echnology OTM-3550-SW is a frequency agile F .C.C. compatible television modulator that will
provide high level output, on any channel from 7.00MHz, Ch. T7 through 547.25MHz, Ch. 78, including all
HRC and IRC output channels. All channels are selectable in 0.25MHz increments by front panel DIP switches.
F .C.C. offsets of +12KHz and +25KHz are also selectable by front panel DIP switches.
The OTM-3550-SW uses SA W filtering for 60dB adjacent channel rejection. This unit also of fers the unique
Olson T echnology feature of >80dB out-of-band carrier to noise ratio which allows virtually unlimited numbers
of the OTM-3550-SW to be combined without the need for external band pass filters. The OTM-3550-SW
is BTSC stereo compatible.
2) CHANNEL SELECTION
Remove the front panel plate marked “Output Channel Select” to expose the channel select and offset select
DIP switches as shown in Figure #1.
OTM-3550-SW
FREQUENCY AGILE - F .C.C. COMP ATIBLE
TELEVISION MODULA TOR
Figure #1
FRONT PANEL DIP SWITCHES
0 = Switch in DOWN Position
1 = Switch in UP Position
1) Select the desired channel by use of the channel select switch and the code sheets.
2) Select the proper offset by use of the offset switch and the offset information on the next page.
3) The example above indicates channel 6 with 0KHz offset.
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OFFSET SELECT INFORMA TION
1) Channels 14 (A), 15 (B), 16 (C), 25 to 41 (L to EE) & 43 to 53 (GG to QQ) = 12.5KHz.
2) Channels 98 (A-2), 99 (A-1) & 42 (FF) = 25KHz.
3) All others = 0KHz.
Offset (3) Rightmost DIP Switches
0KHz 0 1 1
12.5KHz 1 0 1
25.0KHz 1 1 0
3) F .C.C. OFFSET FREQUENCIES
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F .C.C. OFFSET FREQUENCIES (Continued)
4) VIDEO MODULA TION ADJUSTMENT
A) Connect a video source of approximately 1V p-p to the video input connector (75 ohms input Z) on
the rear panel. The video should be of a reasonably bright scene (commercials are usually excellent).
B) The video overmodulation indicator LED may stay on for approximately one minute after the unit is
first turned on. W ait for approximately one minute before adjusting the video modulation control and
observing the LED.
Rotate the video modulation level adjust control slowly clockwise until the video overmodulation LED
just turns on. CAUTION: If the modulation is set too high, compression or lack of contrast will occur
during high intensity scenes.
5) AUDIO MODULA TION ADJUSTMENT
A) Connect an audio source of 500mV p-p (minimum) to the balanced audio input connector (600 ohms
input Z) on the rear panel. The source should be typical of the program material to be carried.
B) Rotate the audio modulation level adjust control slowly clockwise until the audio overmodulation
LED just begins to blink. CAUTION: Overmodulation can result in severe distortion in some TV
sets. Set this control at peak program levels.
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