Olson Technology OTM-4870 - Manual (Page 9)

025-000412 Rev. B Page 9
VIDEO IF IN
This is the video IF input to the SAW filter / output converter section. The AUX IF switch is AFTER this
input. The video IF level at this point should be +38 dBmV.
In normally-configured applications this input is usually connected to the VIDEO IF OUT connector. The
OTM-4870 is shipped from the factory with this jumper in place.
AUDIO IF IN
This is the aural IF input to the SAW 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 at the 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-4870 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 at the 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-4870 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-4870 is shipped from the factory with this jumper in place.
VIDEO IN
1 Volt P-P baseband video input to the OTM-4870. 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-4870.
This input is configurable for 600
Ω
balanced or high impedance unbalanced applications. When configured
for high impedance input, ground should be connected to the right-side terminal.
To change from 600
Ω
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”.
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 “BY
PASS”.