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4. You can connect as many of the channel rows as you wish in this manner,
but remember that each would follow the same non-standard split you have
programmed. Only one such split can be programmed in the AUX matrix
row. It may be changed as needed. If more than one non-standard split is
needed, you can either give up a standard split or devise your own way of
switching in what you need.
+TX (+RPT) OFFSETS
+TX offsets are programmed exactly like the Frequency Programming matrix.
For example, for a +600 KHz offset:
PROGRAMMING THE 'MINUS' OFFSETS
We showed the Plus offsets first to prepare you for the Minus offsets. The
offsets are entered into the FX synthesizer through the binary adders, U7-10.
Notice that we said adders and not subtractors; in binary there is 'no such
animal' as a subtractor. We must use the technique known as 'two's
complement addition' which actually performs a subtraction process! This may
sound complicated, but it really isn't. We simply find 'N' as usual, take its 'two's
complement' and program the result into the offset matrix. We'll show you three
detailed examples.
Don't be alarmed. If all you need is the standard 220 MHz band offsets, just
install the diodes in the offset matrix as clearly illustrated on your PC board.
Understanding the following information is essential ONLY for those who need
to program non-standard Minus or AUX offsets.
First we need to understand some rules for binary addition:
EXAMPLE 1: -1.6 MHz TX Offset
As for the +1.6 MHz offset, N= 1600 ÷ 5 KHz = 320. However, this is the last of
Decimal numbers in this work. We'll have to work with Binary numbers now. In
brief, we set up the complement, or exact inverse of N in binary, and then add
1. This will give us our two's complement that is needed for programming into
our offset matrix.
Binary code for N=320
Now, just INVERT all of the 'bits':
8192 4096 2048 1024
0
0
N= 600 KHz ÷ 5 KHz = 120
1) 0+0=0
2) 1+0=1
3) 1+1=0 and CARRY 1
512
0
0
0
(Carrying is done from right to left)
256
128
1
0
64
32
16
1
0
8
0
0
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