6.6.6 Using AFC Test Mode
In AFC test mode, the Ps command runs normally. AFC information is replaced with a
hexadecimal readout of the present 25-bit value. Your display may look something like:
Navg :3, FIR:1.33 usec (48 Taps), BW:1.000 MHz, DCGain:ZERO
Freq:26.610 MHz, Pwr:64.6 dBm, AFCTest:0000207F (Bits)
1. To enter the AFC test submode, use the Ps plot command and press the | key.
The following list of keybindings are shown. They remain in eect until you exit the test
mode by typing: Q
AFC Test Mode Subcommands
W Use WalkingOnes pattern
P Toggle Pin/Bit numbering
09,AO Toggle AFC Bits 024 (Pins 125)
2 2 2 2 2 1 1 1 1 1 1 1 1 1 1
4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 76
5 4 3 2 1 0
O N M L K J I H G F E D C B A 9 8 7 6
5 4 3 2 1 0
2. Initially, a walking-ones bit pattern is output instead of the normal formatted AFC value.
The walking-ones test is useful as an oscilloscope diagnostic.
To return to it later, type: W.
3. The test pattern shifts a single 1 down through the AFC word, making a transition
approximately every 4 ms. This helps test the wiring for digital AFC installations.
Type 0 ... 9 or A... O to enter a mode for directly controlling a static 25-bit digital AFC
pattern. Each key toggles its corresponding bit, as summarized in the keybindings
printout. You can make any 25-bit pattern by toggling the appropriate bits (initially all
zero) to one.
Within a pattern, you can toggle a bit on and
o to verify its function.
4. Use the P command to choose whether the 25-bit word represents a numeric AFC span
that is mapped into pins in the pin-map table in the Mb menu or whether it represents
those pins directly.
5. The printed hex test value is followed by Bits or Pins.
• In Pins mode, press 0 to toggle Pin-1, 1 to toggle Pin-2, and so on.
The Pins mode is useful when performing initial electrical tests of the wiring of
each pin.
• In Bits mode, press 0 to toggle the pin or pins that are designated to be driven
from Bit-0 of the numeric AFC.
After you have
verified the pin wiring and created the Mb mapping table, use the
Bits mode to test the complete digital AFC interface.
Chapter 6 – Plot-assisted Setups
151
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