EIP 545A - Page 53

Two important I10 port locations are the yig frequency control (address 9840, 9842) and the FCO fre-
quency control (address 9820, 9822).
To convert from the desired yig frequency to the PIA program number:
1.
Round the desired frequency to
a multiple of 2 MHz (The yig DAC resolution is 2 MHz).
2.
Divide the desired frequency in MHz by 2
(Fl2).
3.
Convert
Fl2 from decimal to hexidecimal.
4.
The two most significant digits are programmed to address 9842, and the two least
significant digits
are programmed to address 9840.
To convert from the desired
VCO frequency to the PIA program number:
EXAMPLE (420.75 MHz)
1.
Round the desired frequency to
a multiple of 50 kHz
(The resolution of the VCO frequency is 50 kHz).
2.
Multiply the desired frequency (in MHz) by 5.
...................... 420. 75 X 5 = 2103.75
3.
If the result contains no fractional part, go to step 8.
4.
Multiply only the fractional part by 16
................................. .75 X 16 = 12
.
5.
Add the result to the most significant digit from step 2.
......... MSD of 2103.75 = 2 2 + 12 = 14
6.
Convert the result to hexidecimal.
..................................... .I410 = El6
7. Replace the MSD from step 2 with the result from step 6
and drop the fractional part.
..................................... .2103.75 -El03
8. The two most significant digits are programmed to address 9822, and the two least significant digits
are programmed to address 9820.
Scans by ArtekMedia © 2007