Olson Technology OTR-3550 User Manual

OTR-3550

FREQUENCY AGILE - F.C.C. COMPATIBLE

TELEVISION PROCESSOR

INSTRUCTION MANUAL

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025-000156 REV F 6/25/01

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1) INTRODUCTION

The Olson T echnology OTR-3550 is a frequency agile - F .C.C. compatible television processor . This unit will
select any VHF/UHF/cable/HRC and IRC input channel from 55.25MHz to 801.25MHz, and will provide
high level (+60dBmV) outputs on any channel from 55.25MHz (channel 2) through 547.25MHz (channel
YY). All input channels are selectable in 0.25MHz steps and output channels are selectable in 1MHz steps by
front panel DIP switches, including F .C.C. offsets of +12KHz and +25KHz.

The OTR-3550 uses dual SA W filtering for 60dB adjacent channel rejection and has high level spurious free
output. This unit also offers the unique Olson Technology feature of >80dB out-of-band carrier to noise ratio,
which will allow virtually unlimited numbers of the OTR-3550 to be combined without the need for external
bandpass filters. The OTR-3550 is BTSC compatible and will automatically function with stereo or monaural
audio carriers.

The OTR-3550 has a low power consumption (17 watts @ 115 VAC) for reliable long term operation. This
unit is equipped with a 0.5 amp slo-blo fuse. T o maintain proper performance of unit, replace only with
equivalent fuse.

OTR-3550

FREQUENCY AGILE - F .C.C. COMP ATIBLE

TELEVISION PROCESSOR

2) INPUT CHANNEL SELECTION - DEMODULA TOR

Remove the front panel plate marked “Input Channel Select” to expose the channel select and band select
DIP switches as shown in Figure 1.

FIGURE 1 - INPUT CHANNEL SELECT

A) CHANNEL SELECTION - Channel selection is accomplished by properly setting the 12-position

DIP switches to the corresponding channel code. Channel codes can be selected from figure #2 or
the code card attached to the Input Channel Select cover plate then, set the DIP switches from left
to right. For example - If channel 11 is selected, its corresponding channel code is:

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T o select an HRC input channel, utilize the HRC code chart on page 7 of this manual.
CAUTION: Channel codes for input and output channel select are completely different.

B) BAND SELECTION - Band selection is accomplished by setting the 6-position DIP

switches to the corresponding band. Only three switches are used for this purpose. Band select
codes can be chosen from Figure #2 or the code card attached to the Input Channel Select cover
plate. Then, set the DIP switches from left to right. For example - If band A-3 to Channel 13 is
desired, its corresponding code is:

C) AFC SELECTION - Most off-air TV stations are usually very close to the specified carrier

frequency such that the AFC function need not be used. However, some UHF stations have a
tendency to drift, so it is best to utilize the AFC function. Simply set the AFC switch (fifth switch
from the left) to the down position for automatic frequency control (AFC “ON”). For example - If
AFC is desired on band A-3 to Channel 13, then the set up is:

Off-cable processing should not require AFC, but make sure the proper code sheet (Standard
Channel or HRC) is utilized.

D) INPUT CONNECTION - After an input channel has been selected (Steps A through C), connect an

antenna or cable source to the RF input terminal. Any VHF , UHF or cable source can be connected
to the RF input connector. For optimum video quality response, the input signal level should have a
minimum of +10dBmV . This unit will function with input signal levels as low as -20dBmV. Any signals
below -20dBmV will be squelched by the internal squelch circuit.

3) DEMODULA TOR AGC ADJUSTMENT

A) The demodulator delayed AGC adjustment is factory set for a +5 to +10dBmV threshold. This setting

provides the best signal-to-noise ratio for low level off-air signals.

B ) For cable operation, where high-level adjacent channel signals may be present, adjacent channel

performance may be improved by lowering the AGC threshold level.

C) To adjust the delayed AGC threshold level for cable operation:

1. Connect a cable signal carrying three adjacent channels at a level of +20dBmV maximum to
the RF input connector.

2. Set the input channel select DIP switches to the channel located in the center carrier frequency
(of the three channels).

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3. Adjust the demodulator delayed AGC control (R54) slightly for the least amount of adjacent
channel interference.

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