Olson Technology OTM-4000 User Manual

OTM-4000

FREQUENCY AGILE 750MHz

F.C.C. COMPATIBLE

TELEVISION MODULATOR

INSTRUCTION MANUAL

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E-Mail: [email protected]

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1) INTRODUCTION

The Olson Technology OTM-4000 is a frequency agile, F.C.C. compatible television modulator. This
microprocessor-controlled unit is capable of operation on any frequency from 48MHz to 750MHz and output
frequency selection is possible in 0.0125MHz increments. Output frequencies may be selected in MHz or by
channel designation. Standard, HRC, IRC, or EIA channel plans may be specified. FCC offsets of +12.5KHz
and +25KHz are automatically provided depending on the plan and/or channel chosen.

An RF output level of +60dBmV (minimum) is possible over the operating frequency range of the OTM-4000.
SA W filtering and Olson T echnology system design factors insure an out-of-band carrier-to-noise ratio greater

than 80dB. This allows unlimited numbers of these units to be combined.
The OTM-4000 has many advanced features including a menu/button control system, front panel display of

channel and channel ID text, a manual or loss-of-video controlled auxiliary I.F . input with AGC, selectable
video AGC, external audio subcarrier input, configurable audio input, dual IF loops, BTSC compatibility ,
optional remote control, and more.

OTM-4000

FREQUENCY AGILE 750MHz

F .C.C. COMPATIBLE TELEVISION MODULATOR

2) LOCAL CONTROL OF THE OTM-4000

A.) FRONT P ANEL ADJUSTMENTS:

V ideo and audio modulation levels, video-to-audio carrier ratio, and the RF output level are adjustable
by means of slotted controls accessible through the front panel. There is also a control for the LCD
panel contrast which should be adjusted for proper viewing once the unit is installed.

See section 4 of this manual for more information on these adjustments.

B.) FRONT P ANEL MENU ITEM CONTROLS:

Most features of the OTM-4000 are configurable from the front panel by means of the menu/button
system which includes an LCD panel and 5 buttons. The LCD panel displays the menu(s) and the
currently-selected configuration or value.

The “UP”, “DOWN”, “LEFT”, and “RIGHT” buttons are used to move between menus, to select
configurations, and to change values. All items except tuning mode and channel number/frequency will
instantly change to match the display . A new tuning mode or channel/frequency takes effect only when
you press the “ENTER” button. T o make other changes permanent, press the “ENTER” button.

Note that when changing the output frequency , the unit’s digital synthesizer may become unlocked
momentarily resulting in operation on an undesired frequency until it re-locks. The OTM-4000 will
turn it’ s RF output off anytime the unit is in an unlocked state, thus preventing unwanted interference
when changing channels.

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As illustrated on page 5 below , there are two menu trees; the main menu tree (on the left) and the
sub-menu tree (on the right). The arrows indicate which buttons to press to move around the menus.
Review each menu and the information below to become familiar with the various functions.

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C.) CHANGING MENU ITEMS:

T o change a function or value, select the menu containing the item to change using the “UP”, “DOWN”,
“RIGHT”, and “LEFT” buttons. After selecting the correct menu, press the “RIGHT” button to change
a menu item. If part or all of the bottom row starts flashing, you can change that item.

If the entire bottom row flashes (most items), press the “UP” or “DOWN” button to change it. These
buttons have auto-repeat. For tuning or channel ID (NAME) values, only one character in the bottom
row will flash. The “LEFT” and “RIGHT” buttons select the position to change and the “UP” and
“DOWN” buttons change the value.

When you are through with the change (or if there is no change), pressing the “ENTER” button will
enable the displayed parameter or value, the change mode is exited, and the display will stop
flashing. If you do not press the “ENTER” key , the parameter will return to the original value after a
time-out of about 15 seconds.

3.) SOME MENU-SPECIFIC INFORMA TION

A.) Display of NAME and TUNING:

This is the normal (default) display and is the menu shown as the top left menu on page 5 of this manual.
Y ou can not make any change from this menu. The NAME is programmable from the NAME menu
and the tuning is programmable from the TUNING menu. The display will return to this default after
about 30 seconds of button inactivity

If the programmed TUNING MODE is CHAN, the display will be the channel number. If the
programmed TUNING MODE is FREQ, the display will be the frequency in MHz.

Note that if the TUNING MODE is changed from CHAN to FREQ, the LCD will display the
frequency of the previously-selected channel.

B.) IF INPUT:

This indicates the preferred choice of the normal IF source. A rear panel input or an automatic transfer
could switch to the AUX IF input.

C.) CHANNEL PLAN:

The CHANNEL PLAN determines the OTM-4000 output frequency for a selected channel number .
T ables at the end of this manual list these values.

Note that FCC offsets are automatically provided for the STD and EIA channel plans and that an
offset is applied to all channels in the IRC plan. The HRC channel plan provides no offsets.

D.) NAME:

This menu allows you to program the NAME that appears at the top of the normal (default) display .
Upper case and lower case letters as well as numbers and various symbols are available for use.

E.) COMMAND MODE, BAUD RA TE, and ADDRESS:

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These functions are only used when the OTM-4000 is configured with the optional remote control
feature.

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NOTE: Arrows indicate which keys to
press to move through menus

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4.) FRONT P ANEL CONTROLS AND INDICA TORS

REMOTE

When an OTM-4000 is equipped with the optional remote control feature, this LED when on,
indicates that the OTM-4000 is in the remote control mode.

UNLOCKED

This LED when on, indicates that one of the digital synthesizers is not locked. This condition will result
in shutdown of the RF output as long as the condition exists. Note that this LED will usually flash on
momentarily when changing a channel or frequency . This momentary shutdown of the output prevents
undesired interference to other channels if the OTM-4000 is connected to a system or network when
it’s channel is changed.

VIDEO LEVEL

This control adjusts the video depth-of-modulation. Choose a bright scene (commercials are usually
excellent) and set it carefully while observing the VIDEO O/M LED. This control should be advanced
to a point JUST SHOR T of where the VIDEO O/M LED flashes-on.

VIDEO O/M

This LED, when on, indicates a depth-of-modulation greater than 87-1/2%. It should never be on
continuously but might be on for short periods during bright scenes. See VIDEO LEVEL above.

This LED will stay on for several seconds when power is first applied to the OTM-4000.

AUDIO LEVEL

This control adjusts the audio deviation of the OTM-4000. Choose program material that is of high
average volume when setting this control and adjust it so the AUDIO O/M LED just blinks-on during
program audio level peaks.

AUDIO O/M

This LED, when on, indicates that the peak deviation of the OTM-4000 is at ±25KHz. It should
only flash-on occasionally during normal operation. See AUDIO LEVEL, above.

A/V

This control adjusts the aural carrier level relative to the video carrier level. It is typically adjusted for
an A/V ratio of 15-17dB.

LEFT , RIGHT , UP , DOWN, ENTER

These buttons are used in selecting and changing menu items as displayed on the LCD panel.

CONTRAST

AUX IF

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This control adjusts the LCD panel contrast. Adjust it for best display legibility when the OTM-4000
is placed in operation.

This LED, when on, indicates that the current IF source is the AUX input at the rear panel.

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LCD DISPLA Y P ANEL

This displays menu and status information.

OUTPUT RF LEVEL

This control is used to set the RF output level. If the OTM-4000 is feeding a system or network with
many channels, it is suggested that it be operated at an output level of +55dBmV minimum to prevent
degradation of the C/N ratio of that channel. If lower output levels are required, place an in-line
attenuator at the RF output.

Note that the OTM-4000 may be capable of output levels greater than +60dBmV on some channels.
The specifications for spurious performance, etc are based on a maximum operating level of +60dBmV .
This unit may not meet it’ s full specification if operated at greater that +60dBmV out.

RF ON

This LED indicates the output RF status.

5.) REAR P ANEL CONNECTIONS

RF TEST

This output is approximately 20dB below the main RF output and may be used for monitoring or

test.
RF OUT
HOST IN

This RJ connector is only present when the optional remote control module is installed and it is the

remote control input for the modulator.
NEXT OUT

This RJ connector is only present when the optional remote control module is installed and it is used

to connect a “next” modulator in a site with a group of remotely-controlled OTM-4000’s.
AUX IN

This is the AUX IF input. This input is before the SA W IF section and normally expects an IF input

level of +38 dBmV . It has AGC which will allow levels to vary as much as ±5dB while holding the

RF output level constant.

This input may be enabled by shorting the AUX SELECT terminals on the rear panel, by front panel

control, by loss of video, or by (optional) remote control.
VIDEO IF IN

This is the video IF input to the SA W filter / output converter section. The AUX IF switch is AF-

TER this input. The video IF level at this point should be +38 dBmV.

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In normally-configured applications this input is usually connected to the VIDEO IF OUT

connector. The OTM-4000 is shipped from the factory with this jumper in place.

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AUDIO IF IN

This is the aural IF input to the SA W filter / output converter section. The AUX IF switch is AFTER

this input. The aural IF level at this point is relative to the video IF level as at the unit RF output.

IE: If the A/V ratio at the output is 15dB, then the aural IF level at this point would be

approximately 15 dB below the video IF level at the VIDEO IF IN connector (approximately

+23dBmV).

In normally-configured applications this input is usually connected to the AUDIO IF OUT

connector. The OTM-4000 is shipped from the factory with this jumper in place.
AUDIO IF OUT

This is the aural IF output from the IF modulator section. The aural IF level here is relative to the

video IF level as at the unit RF output. IE: If the A/V ratio at the output is 15dB, then the aural IF

level at this point would be approximately 15 dB below the video IF level at the VIDEO IF IN

connector (approximately +23dBmV).

In normally-configured applications this output is usually connected to the AUDIO IF IN connector.

The OTM-4000 is shipped from the factory with this jumper in place.
VIDEO IF OUT

This is the video IF output from the IF modulator section. The video IF level here is +38dBmV.

In normally-configured applications this output is usually connected to the VIDEO IF IN connector .

The OTM-4000 is shipped from the factory with this jumper in place.
VIDEO IN

1 Volt P-P baseband video input to the OTM-4000. When VIDEO AGC is enabled, the

modulation will remain constant for input level changes of ±3dB.
AUX SELECT

When these two terminals are connected together, the AUX IF IN is enabled. This is a “hard”

control and will override any other function that instructs the internal IF to be selected. The left

terminal is chassis ground and the right terminal is grounded to activate the function.
AUDIO IN

Baseband audio input to the OTM-4000.

This input is configurable for 600Ω balanced or high impedance unbalanced applications. When

configured for high impedance input, ground should be connected to the right-side terminal.

T o change from 600Ω to high-impedance input, disconnect the unit from AC power, remove the top

cover and locate jumper “JMP1” near the front left corner of the circuit board. Move the jumper

from the position marked “BAL” to the position marked “UNBAL”.

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If it is desired to defeat the audio pre-emphasis for baseband BTSC input or other applications,

locate the jumper marked “JMP2” and move it from the position marked “PRE-EMPH” to the

position marked “BYP ASS”.

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EXT SUB IN

External aural subcarrier input. This input is selectable from the front panel or (optional) remote

control. The input level (at 4.5 MHz for NTSC versions) should be +45dBmV (measured into

75Ω). The OTM-4000 has limiter circuitry to keep the aural carrier constant with small changes in

the external subcarrier signal level.
AC LINE POWER INPUT

The OTM-4000 may be powered by 90 to 240 VAC and 47-63 HZ and it draws about 30 Watts.

5.) MISCELLANEOUS

A) When mounting the OTM-4000 in an equipment rack, it is best to leave a blank space above and

below the unit to allow for adequate flow of cooling air.
B.) This unit is equipped with a 0.5A slo-blo fuse which is located at the IEC power input module at the

rear panel. For continued safety and to maintain proper performance of the unit, please replace only

with an equivalent fuse.

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OTM-4000 CHANNEL PLANS

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OTM-4000 CHANNEL PLANS (Continued)

* NOTE: A-1 through A-8 reference designations on this chart do not apply to the EIA channel plan listings.

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OTM-4000 CHANNEL PLANS (Continued)

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