User Manual

EASy-PLUS
®
User Manual
– 23
TRILITHIC
Rev 1.02
SECTION 7
I.F. (Composite I.F., Aux. I.F., Single I.F.) INTERFACE and INSTALLATION
7.1 INTRODUCTION Single I.F. Replacement
Composite I.F. (both visual and aural intermediate carriers on the same coaxial cable) replacement is a technique which
is used to change the program content on a channel without altering the RF output carrier frequency or amplitude. With
this technique you will need to install an I.F. switch in the composite I.F. loop-through on the rear of the modulator or
processor housing (i.e. the channel’s rack mount assembly). Generally, modulators have this I.F. loop on the back of the
housing. In some cases, you may be able to install the loop into the housing to implement this type of switching. For the
E.A.S. application, the alternate I.F. signal will be taken from an independent distribution system which will be explained
as you move through this manual.
Single (Composite) I.F. Switch Installation (SW-1)
The first step when assembling the E.A.S. system is to install an SW-1 or SW-4 switch on the rear of each modulator or
processor. The SW-1 is a three terminal device used to substitute the current I.F. source with an alternative I.F. source.
The SW-4 switch is a two terminal device with a terminal strip localize as a contact-closure for such chassis as the S-A
Continuum modulators and processors.
For each SW-1 installed, you will need two (2) 75 Ohm cables of equal length about three (3) to six (6) inches in length.
The next step will cause a brief interruption of the channel involved while the I.F switch is being connected, but the signal
will return once the switch is installed.
Connect the 75 Ohm cable from the I.F. OUT of the modulator or processor to the I.F. IN of the SW-1 switch. Connect
the I.F. OUT of the SW-1 switch to the I.F. IN of the same modulator or processor. See the following diagram. You will
I.F. signal fed from the LS-16P
Lossless Splitter
Normal I.F. IN fed from the I.F. OUT
of the modulator or processor
Normal I.F. OUT fed to the I.F. IN
of the modulator or processor
EAS IN
SW-1
I.F. OUT I.F.
TRILITHIC