Olson Technology OTR-3550-SW User Manual

OTR-3550-SW

FREQUENCY AGILE - F.C.C. COMPATIBLE

TELEVISION PROCESSOR

INSTRUCTION MANUAL

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E-Mail: [email protected]

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1) INTRODUCTION

The Olson T echnology OTR-3550-SW is a frequency agile, F .C.C. compatible television processor . This unit
will select any VHF/UHF/cable input channel from 55.25MHz to 801.25MHz and will provide high level
(+60dBmV) outputs on any channel from 7.00MHz (T -7) through 547.25MHz (channel 78) including all
HRC and IRC output channels. All input and output channels are selectable in 0.25MHz increments by front
panel DIP switches, including F .C.C. offsets of +12KHz and +25KHz.

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

The OTR-3550-SW has a low power consumption (17 watts @ 115 V AC) 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 an
equivalent fuse.

OTR-3550-SW

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. See page 5 for demodulator switch codes.

Figure #1

INPUT CHANNEL SELECT

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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 #3 or the code
card attached to the Input Channel Select cover plate. Set the DIP switches from left to right.
For example - If channel 11 is selected, then its corresponding channel code is:

0 = Switch in DOWN Position
1 = Switch in UP Position

T o select an HRC input channel, utilize the HRC code chart attached to 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 #3 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, then 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 to the left of band select) 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 +20dBmV.
This unit will function with input signal levels as low as -20dBmV but any signals below -20dBmV will be
squelched by the internal squelch circuit.

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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).

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

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OTR-3550-SW

DEMODULA TOR ST ANDARD CHANNEL SELECT CHAR T

Page 5

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HRC CHANNELS

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4) OUTPUT CHANNEL SELECTION - MODULA TOR

Remove the front panel plate marked “Output Channel Select” to expose the channel select and offset
select DIP switches as shown in Figure #4. See page 1 1 for Modulator switch codes.

Figure #4

OUTPUT CHANNEL SELECT

A) 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 below .

3) The example above indicates channel 6 with 0kHz offset.

Offset Select Information

1) Channels A, B, C, L to W, AA to EE & GG to QQ = 12.5KHz.

2) Channels A-2, A-1 & FF = 25KHz.

3) All others = 0KHz.

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F .C.C. OFFSET FREQUENCIES

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5) 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) Rotate the video modulation level adjust control slowly clockwise until the video overmodulation LED just

turns on. The light may blink with differences in average picture level. CAUTION: If the modulation is set
too high, compression or lack of contrast will occur during high intensity scenes.

6) AUDIO MODULA TION ADJUSTMENT

A) Connect an audio source of 300mV 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.

7) RF AND AURAL CARRIER LEVEL ADJUSTMENT

A) Using a field strength meter, set the video carrier to the desired level with the RF output level adjust control.

B) T une the field strength meter to the aural carrier (4.5MHz above the video carrier).

C) Adjust the aural carrier level control to the desired level, typically 15dB below the video carrier.

CAUTION: Reducing the visual/aural carrier ratio to less than 15dB can result in high out-of-band spuri­ous signals in adjacent channels.

8) MISCELLANEOUS

A) The OTR-3550-SW is BTSC stereo compatible. It is shipped in the “mono” mode. To defeat

pre-emphasis, in order to use a composite BTSC baseband input signal, move the internal jumper plug
from W -9 to W -10. This plug is located in the left front area of the circuit board.

B ) If a scrambling unit is utilized with the OTR-3550-SW, follow the instructions associated with the

scrambler. The video I.F . output level is +40dBmV , and the audio carrier level is determined by the aural
carrier level adjustment - typically +17dBmV @ 15dB A/V ratio.

C) This unit is equipped with a 0.5A slo-blo fuse. For continued safety and to maintain proper performance of

the unit, please replace only with an equivalent fuse.

D) A -20dB test point (type F connector) is provided in the rear panel.

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OTR-3550-SW

ST ANDARD TV CHANNEL - OUTPUT CODES

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ST ANDARD TV CHANNEL - OUTPUT CODES (Continued)

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ST ANDARD TV CHANNEL - OUTPUT CODES (Continued)

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ST ANDARD TV CHANNEL - OUTPUT CODES (Continued)

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OTR-3550-SW

HRC TV CHANNELS - OUTPUT CODES

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OTR-3550-SW

HRC TV CHANNELS - OUTPUT CODES (Continued)

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OTR-3550-SW

HRC TV CHANNELS - OUTPUT CODES (Continued)

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